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DEFINITION OF NEUROPSYCHOLOGY
Neuropsychology is a branch of psychology that studies how the nervous system (particularly
the brain) influence behaviour and mental processes
...

Neuropsychology involves:
•

the study of the relationships between brain function and behaviour
...


•

observation of changes in thoughts and behaviors that relate to the structural or
cognitive function of the brain
...


BRANCHES OF NEUROPSYCHOLOGY
A neurospsychologist has a choice to focus on a number of different areas
...
A person can focus on, experimental neuropsychology, clinical neuropsychology,
paediatric neuropsychology as well as cognitive neuropsychology among others
...
Experimental Neuropsychology: Experimental neuropsychology is an
approach which uses methods from experimental psychology to uncover the
relationship between the nervous system and cognitive function
...
A neurospsychologist will conduct research into the
effects of brain trauma and degenerative diseases as well as looking at ways to
help a patient cope with the effects of brain disorders
...


Some of the cognitive abilities that an experimental neuropsychologist will investigate
include perception, motor control, language and memory
...


A neuropsychologist will also research the effects of specific brain injuries as well as
neurological developmental disorders and neurodegenerative disorders
...
ADHD, cerebral palsy and Down's syndrome are also areas of study for a
neuropsychologist
...


2
...

A clinical neuropsychologist will take the research developed from experimental
neuropsychology and apply it in a clinical setting
...


Once the clinical neuropsychologist has gathered this information, the neuropsychologist will
typically use the information to identify any neurological problems as well as plan and
implement a treatment plan to deal with any of the identified problems
...
The
assessment can be a normative assessment or an individual assessment
...


A normative assessment is usually conducted when the neuropsychologist wants to assess the
amount of damage resulting from a brain injury or stroke
...


An individual assessment, like the normative assessment, is done on an individual but instead
of comparing the result to a representative sample, the test results are compared to earlier test
results done on the same individual
...
These test
results may still be compared to a representative sample to see how the client compares to the
average population
...
This history
will typically include a medical and psychological history as well as information about a
client's education and job history
...

The patient history will also give the neuropsychologist information about the client's
motivation and temperament
...
Neurological testing looks at a number
of cognitive abilities such as visual perception, reasoning, learning and memory
...
Once these basic
neurological functioning tests are completed, the neuropsychologist may decide to do more
in-depth testing and assessment of one aspect of a client's cognitive functioning
...
The treatment plan itself could involve making referrals to
specialized services such as an occupational therapist, a speech therapist or even another
clinical psychologist to help the patient deal with any behavioral or emotional issues arising
as a result of a brain disorder
...


Cognitive Compensation: Cognitive compensation is a strategy where the neuropsychologist
develops a plan to teach a client how to compensate for any weaknesses in functioning
...
For example, a person who is experiencing poor visual
memory because of a brain injury could be taught how to use verbal memory aids to help
remember the information
...
Cognitive remediation is
simply a set of repetitive exercises designed to help a patient improve a variety of abilities
such as attention, memory, planning and executive functioning
...

Most cognitive remediation strategies can be practiced using a computer program
...

Even though a clinical neuropsychologist will be primarily involved with assessment and
treatment planning, good clinical psychology skills are still needed to help people feel more
comfortable in the testing situation as well as making people more willing to discuss their
difficulties
...


3
...
A pediatric neuropsychologist will be involved in assessing and
treating children who either have or may have some form of brain injury,
neurodevelopmental disorder or other congenital disorder
...


4
...
Some of the cognitive functions that a
cognitive neuropsychologist looks at include how memories are produced,

how we produce language as well as how we are able to recognize objects and
people
...
A cognitive neuropsychologist will also
look at brain injuries and how they relate to an inability to perform certain
cognitive functions
...

The lesion method is used when the cognitive neuropsychologist knows exactly which areas
of a person's brain are damaged
...


A cognitive neuropsychologist uses a number of different technologies such as PET scans,
fMRIs and EEGs
...
PET scans record low level radiation coming from the brain while fMRIs
measure the brain's magnetic signal
...
These tests are also used by other neuropsychologists to conduct
assessments
...
Forensic Neuropsychology: Forensic neuropsychology is the intersection
between psychology and the criminal justice system
...

A forensic neuropsychologist works with the court system providing assessments to
determine the effects of brain trauma
...
For example, a forensic neuropsychologist may be called upon to evaluate a
patient who has been hit by a car
...


WHERE DOES A NEUROPSYCHOLOGIST WORK?

A neuropsychologist has the opportunity to work in a number of different settings depending
on your interest
...

In addition to research at a university, a neuropsychologist can also teach about
neuropsychology and neuropsychological testing
...
You would investigate if a
new drug has any harmful or beneficial effects on brain functioning and cognitive ability
...


Hospital Settings: A neuropsychologist may find work in a hospital or regional neuroscience
centre working with patients who are suffering from the effects of trauma, neurosurgery or
neurological disease
...


Rehabilitation Centers: In addition to acute settings, a neuropsychologist can also work in a
rehabilitation center helping to provide treatment to patients after the acute phase has passed
...
The neuropsychologist would help patients minimize the effects of any
brain trauma or disease, as well as help the patient learn the skills necessary to function in
regular society
...
The neuropsychologist would provide continuous assessment as
well as training to help the patient remain in the community
...


Regardless of the setting where you find work as a neuropsychologist, you will be called
upon to do a number of different assessments to determine if there are any problems with a
person's behavior, emotions or thinking ability as a result of brain trauma or disease
...


Goals of Neuropsychology
1
...


•

Secondly, to understand the nature of any brain injury or resulting cognitive
problem (see neurocognitive deficit) and its impact on the individual, as a
means of devising a rehabilitation programme or offering advice as to an
individual's ability to carry out a certain tasks (for example, fitness to drive, or
returning to work)
...

A better understanding of the organization and functioning of normal
psychological processes contributes to a better understanding of patients’
impairments: the clinical goals of cognitive neuropsychology are the
elaboration of new evaluation and rehabilitation methods
...


Neuropsychology helps doctors understand how brain malfunctions occur, and what
happens when they do
...


By testing a range of cognitive abilities and examining patterns of performance in
different cognitive areas, neuropsychologists can make inferences about underlying
brain function
...


Neuropsychological testing can help in planning and developing remedial education,
rehabilitation and vocational programs for individuals with neurological or
developmental problems
...


History of Neuropsychology
Evidence of Early Neuropsychology: Trephanation
Trephanation is the ancient surgical procedure of operating on the human skull by
scraping, chiseling, or cutting bone from the skull
...

Results suggest that most trephanations were performed in the frontal and upper
parietal regions following injury to the skull from clubs and other weapons of the
pre-Columbian era
...
Techniques used were similar to modernday methods of drilling "burr holes" to relieve pressure and release trapped blood
...
This papyrus represents the earliest
written record of medical treatment
...
These descriptions suggest, for the first time,
that brain functions are localized in specific parts of the brain
...
Leitner):

These are references to weakness on one side of the body
(hemiplegia) and the build-up of pressure, probably a
blood-clot in this case
...
Of course, hemiplegia

occurs on the side opposite to the lesion
...

Ancient Greeks:
Unfortunately, the knowledge of brain function at that time was limited by the
strong aversion to dissecting the brain
...
This theory
explained that people with heavy upper bodies were intellectualy dull due to the
extra weight bearing on the heart
...
Aristotle
identified the heart as "the most important organ of the body," and the first to form
according to his observations of chick embryos
...
Aristotle described it as a threechambered organ that was the center of vitality in the body
...
g
...

Why? Importance: After death, the heart was weighed to see if one would enter
into eternal afterlife, but the brain was usually discarded
...
The mind
(or soul) is a nonphysical entity, which somehow interacts with the material body
...
According to Aristotle, the mind and body
interacted through a "point of interaction" which he identified as the heart
...
"
Pythagoras (550 BC, best known for the Pythagorean theorem) was one of the first
to propose that the thought processes and the soul were located in the brain and not
the heart
...
(Pytharoras also claimed
to have lived four lives that he could remember in detail, and heard the cry of his
dead friend in the bark of a dog
...
The
Hippocratic school held that all illness was the result of an imbalance in the body
of the four humours, fluids which in health were naturally equal in proportion
(pepsis)
...
Hippocratic therapy
was directed towards restoring this balance
...
The theory was proposed
by Nemesius and Saint Augustine in approximatley 130-200 A
...
It was strongly
influenced by the anatomical studies of Galen (see below) in the second century,
in which he described the ventricles in detail and developed his own theory of
"psychic gases and humours", that flowed through the body and ventricles (thus,
the "ventricular localization hypothesis"), giving rise to mental functions
...
) The idea that the veltricles
were merely a sewer system through which passed bodily fluids, led to the theory
of the importance of "humors" which has persisted for 1000 years
...
These
images depict the connections between the senses (vision, hearing etc
...
Cognitive functions were then
arrayed from front to back in the ventricles
...

From this period, many important discoveries and theories were noted
...
As well, the discovery of ascending
(sensory) and descending (motor) nerves occurred
...
During this time he gained experience treating
trauma and wounds, which he later called "windows into the body"
...
From
these studies, Galen identified many of the major brain structures and described
behavioral effects following brain trauma
...


Pneuma traveled through nerves, which Galen believed were tubes, throughout the
body - sent out from the brain to the muscles (i
...
, controlled by the mind, causing
the body to move) and sent back to the brain due to sensory stimulation
...
Galen also showed that pressing on the heart in human
subjects did not lead to loss of consciousness or loss of sensation but severing the
spinal cord in animals abolished sensory responses after brain stimulation
...
He
represents the beginning of a period in which careful observations and empirical
science began to triumph over the ideas that had been handed down since the time
of Aristotle and Galen (e
...
, recognized their mistakes)
...
Vealius made carefuldiagrams of human anatomy
...
g
...
He believed that all mental functions were located in
the pineal gland, a small centrally-located brain structure which is now believed to
play a role in sleep/wake and dark/light cycles
...


Descartes did subscribe to some of Galen's theories (that the brain was a reservoirr
of fluid), as demonstrated by one of his illustrations, in which the fire displaces the
skin, which pulls a tiny thread, which opens a pore in the ventricle (F) allowing the
"animal spirit" to flow through a hollow tube, which inflates the muscle of the leg,
causing the foot to withdraw
...


Phrenology:
Gall (1758-1828) introduced the idea that the brain
was comprised of separate organs, each localized
and responsible for a basic psychological trait
...

Phrenology correlated the mental faculties
described by philosophers with the development of
specific brain areas
...
These bumps could be analyzed and
a Phrenology practitioner could determine the
subject's personality and intelligence from analysis
of the skull, called cranioscopy
...
Men were believed to have larger "social regions" with more "pride,
energy, and self-reliance", as compared to female skulls which were thought to
possess more "inhabitivness (love of home), a lack of firmness and self esteem
...

So, there is no relationship between the bumps on the skull and the underlying
brain tissue, nor is there a relationship between the size of an area of brain and the
size of the function that it supports (skulls are hard, brains are not)
...
There are numerous
phrenological charts, heads, and hands, with many for sale
...
The patient could

accurately comprehend language
...
If you
look carefully at the brain, you can detect a soft, fluid-filled area in the frontal
lobe
...
The third convolution of the inferior
posterior frontal lobe has since become known as "Broca's area", and patients with
damage to Broca's area are referred to as having "Broca's aphasia"
...
This resulted in the idea that component processes of language were
localized
...
This
doctrine states that complex mental functions, such as language, represent the
combined processing of a number of subcomponent processes represented in
widely different areas of the brain
...
Such
faculties, if they have validity at all, are the result of a number of primary cognitive
operations
...
He postulated that lesions in the
subcortical areas could produce similar behavioral disorders
...
He asserted that
while sensory input was localized, to an extent, at an elementary level, the more
comples process of perception was dependent on the entire brain (Luria later
explained this in terms of primary, secondary and tertiary zones)
...
Flourens
also offered the notion of equipotentiality of brain tissue, or that if there is enough
intact tissue following brain damage, the remaining tissue will compensate and
take over the function of the missing area
...

Munk (1839-1912) produced temporary "mind-blindness" in dogs following
lesions in their association cortex
...
e
...
" Following lesions to the association cortex of the
right hemisphere, Babinski (1857-1932) described a similar unawareness of
deficit
...
While the specific area of the lesion had no effect on subsequent
performance, Lashley found that the amount of brain tissue removed from rat
brains effected the ability to negotiate previously learned mazes
...


THE NEURONS
A neuron is a cell specialized to conduct electrochemical impulses called nerve impulses or action
potentials
...
Sensory neurons: In the nervous system, afferent neurons (otherwise known as sensory,
receptor neurons, and afferent axons[1]), carry nerve impulses from receptors or sense organs
toward the central nervous system
...

The sensory neurons in the skin are sensitive to pressure, temperature and pain
...
Those in the tongue and nose respond differently to different shapes of molecules, providing
the information about them that produces taste and smell
...
There are sensory
neurons in the skin, muscles, joints, and organs that indicate pressure, temperature,
and pain
...
Neurons in the
inner ear are sensitive to vibration, and provide us with information about
sound
...

2
...
Motor neurons carry signals from the brain and spinal cord to muscles
...
They translate signals from the brain into muscle
movements and attach directly to the muscles, causing them to contract or relax
...


Motor neurons are able to stimulate muscle cells throughout the body, including
the muscles of the heart, diaphragm, intestines, bladder, and glands
...
Interneurons:
Interneurons act as bridges among other neurons
...
They also pass signals to one another
...

The central nervous system(brain and spinal cord) are composed entirely of interneurons
...


Interneurons are the neurons that provide connections between sensory and motor
neurons, as well as between themselves
...

Most neurons are collected into "packages" of one sort or another, sometimes
visible to the naked eye
...
A fiber made up of many
axons is called a nerve
...
Areas that include large number of cell bodies are called gray
matter
...
Dendrites- receive information from the neuron adjacent
...
Soma- the actual body of the neuron that contains nucleus
3
...
Synapse- distance between 2 neurons
5
...
Neurotransmitter-chemicals used to relay, amplify, and modulate signals between neurons and
other cells
7
...


The main portion of the cell is called the soma or cell body
...

Neurons have a large number of extensions called dendrites
...
It is primarily the
surfaces of the dendrites that receive chemical messages from other neurons
...
Although in
some neurons, it is hard to distinguish from the dendrites, in others it is easily
distinguished by its length
...
In the
neurons that make up the nerves running from the spinal cord to your toes, the
axons can be as long as three feet!
Longer axons are usually covered with a myelin sheath, a series of fatty cells
which have wrapped around an axon many times
...
They serve a similar function as the insulation
around electrical wire
...
It is there that the
electro-chemical signal that has travelled the length of the axon is converted into a
chemical message that travels to the next neuron
...
For every neuron, there are between 1000 and 10,000 synapses
...

•
•
•
•
•
•
•

Nucleus - contains genetic material (chromosomes) including information for cell
development and synthesis of proteins necessary for cell maintenance and survival
...

Nucleolus - produces ribosomes necessary for translation of genetic information into
proteins
Nissl Bodies - groups of ribosomes used for protein synthesis
...
Can have ribosomes (rough ER) or no ribosomes (smooth ER)
...

Golgi Apparatus - membrane-bound structure important in packaging peptides and
proteins (including neurotransmitters) into vesicles
...

Mitochondria - produce energy to fuel cellular activities
...
The process of
communicating information is very similar, whether it is to another neuron
or to a muscle or gland cell
...

The transmission of information is accomplished in two ways:
•

•

Electrically: the neuron is directly adjacent to other neurons
...

Chemically: there is a space (the synaptic cleft) between the axon
terminus and the adjacent neuron
...


Synapse Structure
•
•
•
•
•

The part of the synapse that belongs to the initiating neuron is called
the presynaptic membrane
...

The space between the two is called the synaptic cleft
...

Presynaptic terminals contain numerous synaptic vesicles
Synaptic vesicles contain Neurotransmitters, chemical substances
which ultimately cause postsynaptic changes in the receiving neuron,
is contained within the synaptic vesicles
...
k
...
, noradrenaline)
o Serotonin

Electrical transmission (from one end of neuron to the other)
The action potential
When chemicals contact the surface of a neuron, they change the balance
of ions (electrically charged atoms) between the inside and outside of the cell
membrane
...
When it reaches the axon, it initiates the action
potential, which is a rapidly moving exchange of ions
...
When the charge enters the axon, the ion channels at the base
of the axon allow positively charged ions to enter the axon, changing the electrical
balance between inside and outside
...


In this little diagram, the red represents the positive ions going into the axon, while
the orange represents positive ions going out
...
2 to 250 miles per hour!

The chemical transmission (from neuron to neuron)
When the action potential reaches the axon ending, it causes tiny bubbles of
chemicals called vesicles to release their contents into the synaptic gap
...
These sail across the gap to the next
neuron, where they find special places on the cell membrane of the next neuron
called receptor sites
...
When they meet, they open a passage way for ions, which then change the
balance of ions on the outside and the inside of the next neuron
...


While most neurotransmitters are excitatory -- i
...
they excite the next neuron -there are also inhibitory neurotransmitters
...


Electrical transmission occurs by virtue of the fact that the cells are in direct
contact with each other: depolarization of the presynaptic cell membrane
causes a depolarization of the postsynaptic cell membrane, and the action
potential is propagated further
...

Chemical transmission, albeit more complex allows for far more control,
including the ability to excite or inhibit the postsynaptic cell
...

The sequence of events that lead to postsynaptic changes is as follows:
1
...

2
...


3
...

4
...

5
...

6
...
This process is called exocytosis
...
The neurotransmitter diffuses through the synaptic cleft and binds
with receptor channel membranes that are located in both
presynaptic and postsynaptic membranes
...
The time period from neurotransmitter release to receptor channel
binding is less than a millionth of a second
...

The brain uses neurotransmitters to tell your heart to beat, your lungs to
breathe, and your stomach to digest
...

Neurotransmitter levels can be depleted many ways
...
Stress, poor diet, neurotoxins, genetic predisposition, drugs
(prescription and recreational), alcohol and caffeine usage can cause these
levels to be out of optimal range
...

Excitatory neurotransmitters are not necessarily exciting – they are what
stimulate the brain
...
Inhibitory neurotransmitters balance mood and are
easily depleted when the excitatory neurotransmitters are overactive
...
It allows the signal to go
...
Without a
functioning inhibitory system to put on the brakes, things (like your mood)
can get out of control
EXAMPLES
Excitatory Neurotransmitters
DOPAMINE is our main focus neurotransmitter
...
It is involved in movement, motivation, and emotion, Dopamine
produces feelings of pleasure when released by the brain’s reward system, and
it’s also involved in learning
...

When dopamine is either elevated or low – we can have focus issues such
as not remembering where we put our keys, forgetting what a paragraph
said when we just finished reading it or simply daydreaming and not being
able to stay on task
...
Stimulants such as medications for ADD/ADHD and caffeine
cause dopamine to be pushed into the synapse so that focus is
improved
...

Dopamine is responsible for motivation, interest, and drive
...
When we don't have enough of it we don't feel alive, we
have difficulty initiating or completing tasks, poor concentration, no

energy, and lack of motivation
...

Low Dopamine levels can drive us to use drugs (self medicate), alcohol,
smoke cigarettes, gamble, and/or overeat
...
g
...


Parkinson’s disease is linked to reductions in dopamine (and dopamine agonists
may be used to treat it)
...
This neurotransmitter can cause
ANXIETY at elevated excretion levels as well as some “MOOD
DAMPENING” effects
...

Norepinephrine also known as noradrenaline is a excitatory
neurotransmitter that is produced by the adrenal medulla or made from
dopamine
...
Low levels are linked to lack of energy,
focus, and motivation
...
This neurotransmitter will often be elevated when ADHD like
symptoms are present
...
Epinephrine also regulates
HEART RATE and BLOOD PRESSURE
...
It
regulates attention, mental focus, arousal, and cognition
...

Epinephrine is made from norepinephrine and is released from the adrenal
glands
...
High levels have been linked to sleep problems,
anxiety and ADHD
...
It is the
most common neurotransmitter, it’s released in more than 90% of the
brain’s synapses
...
Low levels can
lead to tiredness and poor brain activity
...
Dysfunction in
glutamate levels are involved in many neurodegenerative diseases such as

Alzheimer's disease, Parkinson's, Huntington's, and Tourette's
...

Acetylcholine: A common neurotransmitter used in the spinal cord and
motor neurons to stimulate muscle contractions
...

Alzheimer’s disease is associated with an undersupply of acetylcholine
...


Inhibitory Neurotransmitters
SEROTONIN is an inhibitory neurotransmitter – which means that it does
not stimulate the brain
...
Adequate amounts of serotonin are
necessary for a stable mood and to balance any excessive excitatory
(stimulating) neurotransmitter firing in the brain
...
Serotonin also regulates many other processes such as
carbohydrate cravings, sleep cycle, pain control and appropriate
digestion
...

Serotonin imbalance is one of the most common contributors to mood
problems
...
Serotonin
is key to our feelings of happiness and very important for our emotions
because it helps defend against both anxiety and depression
...
You may have a
shortage of serotonin if you have a sad depressed mood, anxiety, panic
attacks, low energy, migraines, sleeping problems, obsession or
compulsions, feel tense and irritable, crave sweets, and have a reduced
interest in sex
...
Moreover, daily stress can greatly reduce
your serotonin supplies
...
Endorphins are natural pain
relievers
...
The release of endorphins creates the
runner’s high that is experienced after intense physical exertion
...
GABA (Gamma amino butyric
acid) GABA is the major inhibitory neurotransmitter in the central nervous
system
...
It regulates norepinephrine, adrenaline, dopamine, and
serotonin, it is a significant mood modulator
...
Alcohol
stimulates the release of GABA, which inhibits the nervous system and
makes us feel drunk
...
Histamine helps control the sleep-wake cycle and
promotes the release of epinephrine and norepinephrine
...
Low histamine levels can contribute to paranoia, low libido,
fatigue, and medication sensitivities
...


Dopamine –
correlated with movement, attention, and learning

Too much dopamine has been associated with schizophrenia, and too little is associated
with some forms of depression as well as the muscular rigidity and tremors found in
Parkinson’s disease
...


Epinephrine –
involved in energy, and glucose metabolism
Too little epinephrine has been associated with depression
...
Some antidepressant medications increase the
availability of serotonin at the receptor sites
...
Some antianxiety
medication increases GABA at the receptor sites
...
We don’t know what other variables may
be affecting both the neurotransmitter and the mental illness, and we don’t know if the

change in the neurotransmitter causes the illness, or the illness causes the change in
the neurotransmitter
...

However, we can group all the effects into whether the drug increases the
effect of the neurotransmitter at the synapse or decreases it
...
If it
decreases the effect of the neurotransmitter it is called an antagonist
...
If the neurotransmitter is excitatory, an agonist will increase the
excitatory effect, and an antagonist will decrease the excitatory effect
...
Drugs,
depression, anxiety and other mood disorders are thought to be directly
related to imbalances with neurotransmitters
...

Drugs can affect any of the stages in the "life-cycle" of a neurotransmitter
...
When an agonist is ingested, it binds to the
receptor sites in the dendrites to excite the neuron, acting as if more
of the neurotransmitter had been present
...
Because dopamine

produces feelings of pleasure when it is released by neurons, cocaine
creates similar feelings when it is ingested
...
e
...

Antagonists: An antagonist is a drug that reduces or stops the normal
effects of a neurotransmitter
...
As an
example, the poison curare is an antagonist for the neurotransmitter
acetylcholine
...

They have the opposite effect of agonists by blocking the receptors and
inactivating it (usually by taking up the space but without specifically
causing the opening of the channel or the operation of the secondary
messenger)
...
Still
other drugs work by blocking the reuptake of the neurotransmitter itself—
when reuptake is reduced by the drug, more neurotransmitter remains in
the synapse, increasing its action
...

Non-smokers: Nausea,
vomiting, cramps, and
diarrhea
...
Reduces flow of
Ca2+ into cells
2
...
Increases number of
binding sites for glutamate
4
...

Moderate to high doses effect
is inhibitory
...


norepinephrine

Reduced desire for sleep and
food
...

Suppresses cough and
diarrhea

LSD

Serotonin receptor agonist

Visual hallucinations

METHODS USED IN STUDY OF NEUROPSYCHOLOGY
Psychologists Study the Brain Using Many Different Methods
The brain's functions can be studied in many ways: effects of brain damage,
effects of electrical, chemical (and recently magnetic) stimulation of the
brain, measurement of electrical and chemical activity of the brain, and
computer-based brain scans, which show structure or function of the brain
through the intact skull
...
For example, damage in the front end of the
brain disturbs the ability to make decisions and to inhibit socially
inappropriate behaviors
...


•

Effects of electrical and chemical stimulation
...
For example, James
Olds and Peter Milner (1954; Olds, 1967) used electrical
stimulation of small brain areas in rats to find a system in the
brain that is closely tied to reward
...
Psychologically active medications (like
antischizophrenic medications, anesthetics, antianxiety medications)
and recreational drugs (like nicotine in tobacco, LSD, heroin, cocaine)
selectively affect different mental processes because they selectively
act on the brain in different specific brain systems
...

Such experiments have helped identify the location and function of
brain systems that mediate (~carry out) the effects of these chemicals
...
Lesions Provide a Picture of What Is Missing

•

A lesion is the removal or destruction of part of the brain
...
By removing parts of the brain we were able to
learn what different parts of the brain do
...
Brain lesions were
commonly used in the mid 1900s to control mentally unstable
patients
...


•

The brains of living human beings may be damaged, for instance, as
a result of strokes, falls, automobile accidents, gunshots, or tumors
...
In rare occasions, brain lesions may
be created intentionally through surgery, such as that designed to
remove brain tumors or (as in split-brain patients) to reduce the
effects of epilepsy
...
In so doing,
they hope to be able to draw inferences about the likely functions of
human brains from the effects of the lesions in animals
...
For instance, when an individual suffers a stroke, a blood
clot deprives part of the brain of oxygen, killing the neurons in the
area and rendering that area unable to process information
...
For instance,
if the stroke influences the occipital lobe, then vision may suffer, and
if the stroke influences the areas associated with language or speech,
these functions will suffer
...


One of the most striking examples of this form of neuropsychology was carried out on a railroad construction
worker
...
This destroyed his left frontal lobe and changed his personality so much that his friends described him

as “no longer Gage
...


Areas in the frontal lobe of Phineas Gage were damaged when a metal rod
blasted through it
...
The accident
helped scientists understand the role of the frontal lobe in these processes
...
For instance, consider the well-known case of Phineas
Gage, a 25-year-old railroad worker who, as a result of an explosion, had
an iron rod driven into his cheek and out through the top of his skull,
causing major damage to his frontal lobe (Macmillan, 2000)
...
The
amiable, soft-spoken Gage had become irritable, rude, irresponsible, and
dishonest
...

Recording Electrical Activity in the Brain
EEG (Electroencephalogram)
In addition to lesion approaches, it is also possible to learn about the brain
by studying the electrical activity created by the firing of its neurons
...
The EEG is a technique that
records the electrical activity produced by the brain’s neurons through the
use of electrodes that are placed around the research participant’s head
...
The patterns of electrical activity vary depending on the participant’s
current state (e
...
, whether he or she is sleeping or awake) and on the tasks
the person is engaging in
...
If you are awake it measures
what we call alpha waves (short active waves) and when you are asleep it
measures other waves like delta waves (long inactive waves)
...

An EEG can show if a person is asleep, awake, or anesthetized because the
brain wave patterns are known to differ during each state
...
A particular advantage of EEG is that the participant can move
around while the recordings are being taken, which is useful when

measuring brain activity in children who often have difficulty keeping still
...

Neuroimaging
MRI
MRI stands for magnetic resonance imaging and looks at the structure of a
person's brain
...
Magnetic resonance
imaging uses magnets to produce an image of what areas of a person's
brain are active
...
The magnetic field causes the nuclei of
the brain cells to line up
...


fMRI (Functional Magnetic Resonance Imaging)
Although the EEG can provide information about the general patterns of
electrical activity within the brain, and although the EEG allows the
researcher to see these changes quickly as they occur in real time, the
electrodes must be placed on the surface of the skull and each electrode
measures brain waves from large areas of the brain
...


Functional magnetic resonance imaging (fMRI) is a type of brain scan that
uses a magnetic field to create images of brain activity in each brain area
...
Neurons that are firing use more oxygen, and the need
for oxygen increases blood flow to the area
...

Very clear and detailed pictures of brain structures can be produced via
fMRI
...
The images of
these slices are taken repeatedly and are superimposed on images of the
brain structure itself to show how activity changes in different brain
structures over time
...
g
...
Another advantage of the fMRI is that is it noninvasive
...

Although the scanners themselves are expensive, the advantages of fMRIs
are substantial, and they are now available in many university and hospital
settings
...


The fMRI creates brain images of brain structure and activity
...


TMS
There is still one more approach that is being more frequently
implemented to understand brain function, and although it is new, it may
turn out to be the most useful of all
...
In TMS studies the research participant is first scanned in an
fMRI machine to determine the exact location of the brain area to be tested
...
If the participant’s ability to perform the task
is influenced by the presence of the stimulation, then the researchers can
conclude that this particular area of the brain is important to carrying out
the task
...
When the TMS pulses are applied, the brain region
becomes less active, and this deactivation is expected to influence the
research participant’s responses
...
TMS is also
used as a treatment for a variety of psychological conditions, including
migraine, Parkinson’s disease, and major depressive disorder
...
It gives us a 3D
picture of the brain which is great for locating tumors, but it does NOT
show brain activity or function
...

The subject is given an injection of a radioactive substance that is
absorbed by brain tissue, providing an outline of the structure
...


PET Scan (Positron Emission Tomography)
A PET scan is the best way for us to see activity in the brain
...
If a patient seems to be
using alot of the substance in a certain part of the brain, we can tell what
part of the brain is working
...

A PET scan shows how organs and tissues are working
...
The
subject is given an injection of radioactive glucose
...
In this image the subject on the left was asked to
listen subjectively to sequences of musical notes, Note that the
subjective experience was focused in the right hemisphere, whereas the
analytical experience was focused in the left hemisphere
...

A disrupted flow of water indicates where there could be an underlying abnormality
...
This
may include surgery
...
The DTI can pick up the underlying
abnormality in one in three of the remaining 20 per cent
...
All behaviour begins with perception
...
Through the
perceptual process, we gain information about properties and elements of the environment
that are critical to our survival
...

Perception includes the five senses; touch, sight, taste smell and taste
...
It also involves the cognitive processes required to process
information, such as recognizing the face of a friend or detecting a familiar scent
...
This process is
continual, but you do not spend a great deal of time thinking about the actual process that
occurs when you perceive the many stimuli that surround you at any given moment
...
The subtle changes in pressure against your skin
that allow you to feel object occur without a single thought
...


1
...

3
...

5
...

7
...


The Steps in the Perceptual Process
The Environmental Stimulus
The Attended Stimulus
The Image on the Retina
Transduction
Neural Processing
Perception
Recognition
Action

The Environmental Stimulus

The world is full of stimuli that attract our attention through various senses
...

This might include anything that can be seen, touched, tasted, smelled or heard
...


For example, imagine that you are out on a morning jog at your local park
...
The tree branches are swaying in the slight breeze; a man is out on the grass
playing fetch with his Golden Retriever; a car drives past with the windows rolled down and
the music blaring; a duck splashes in a nearby pond
...


The Attended Stimulus
The attended stimulus is the specific object in the environment on which our attention is
focused
...
In other instances, we are likely to
attend to stimuli that have some degree of novelty
...
The duck represents the attended
stimulus
...

The Image on the Retina

Next, the attended stimulus is formed as an image on the retina
...
The cornea helps focus the light as it enters the eye, and the iris of the eye controls
the size of the pupils in order to determine how much light to let in
...

As you might already be aware, the image on the retina is actually upside down from the
actual image in the environment
...
The image has still not been perceived, and this visual information will be
changed even more dramatically in the next step of the process
...
This allows the visual messages to be transmitted to the brain to be
interpreted
...

The back of the eye contains three different cell layers: photoreceptor layer, bipolar cell
layer and ganglion cell layer
...

Cones are responsible for color perception
...
Photoreceptors contain within them a special chemical called a photopigment, which
are embedded in the membrane of the lamellae; a single human rod contains approximately
10 million of them
...
[20] There are 3 specific photopigments (each with their own color) that respond to
specific wavelengths of light
...

If the appropriate photopigment is not in the proper photoreceptor (for example, a green
photopigment inside a red cone), a condition called color vision deficiency will occur
...
These cells contain proteins known as rods
and cones
...

The rods and cones contain a molecule called retinal, which is responsible for transducing
the light into visual signals that are then transmitted via nerve impulses
...
The path followed by a particular
signal depends on what type of signal it is (i
...
an auditory signal or a visual signal)
...
In our previous example, the image of
duck floating in the pond is received as light on the retina, which is then transduced into an
electrical signal and then processed through the neurons in the visual network
...
It is at this point that we become consciously aware of the stimulus
...
At the perception stage, you have become aware of that there is something
out on the pond to perceive
...
In the next stage of the
perceptual process, we will sort the perceived information into meaningful categories
...
It is also
necessary for our brain to categorize and interpret what it is we are sensing
...

Continuing our example, it is at the recognition stage of the perceptual process that you
realize that there is a duck floating on the water
...
By placing objects in
meaningful categories, we are able to understand and react to the world around us
...
This could involve a variety of actions, such as turning your head for
a closer look or turning away to look at something else
...
This might involve a major action, like
running toward a person in distress, or something as subtle as blinking your eyes in response
to a puff of dust blowing through the air
...
This system operates on sequences of
frequency-modulated pulses sent between two neurons in communication
...
Retinal Processing
...

The photoreceptors pointing up; thus, the front of the eye is pointing down, so that light first
hits the bottom layer and progresses through the various layers, until it stimulates the rods
and cones
...

There are four neuron layers within the retina that perform initial image processing on the
stimulations resulting from the individual photoreceptors, the cones and rods
...

These four layers are composed of individual types of neuron cells, based on their
connectivity properties:
• horizontal cells 3
...


The sense of smell

The brain transforms sensory messages into conscious perceptions almost instantly
...

When an animal or a person sniffs an odorant, molecules carrying the scent are captured by
a few of the immense number of receptor neurons in the nasal passages; the receptors are
somewhat specialized in the kinds of odorants to which they respond
...

The olfactory bulb is a structure found in the brains of vertebrates that processes
information about odors, and is a key part of the neural system responsible for the sense of
smell
...
It then serves as a pathway for that input to travel to different locations in the rest of
the brain
...
Within the brain, the bulb is located in the
forebrain, though in humans it sits at the bottom while in other vertebrates it sits at the very
front
...
It is divided into two sections, the main section and the accessory
section
...
Those receptors send signals along their axons, which are the parts of the
cells that carry information away from them
...

They form spherical clusters known as glomeruli, which in turn interact with neurons known
as mitral cells
...


The number of activated receptors indicates the intensity of the stimulus, and their location
in the nose conveys the nature of the scent
...

The bulb analyzes each input pattern and then synthesizes its own message, which it
transmits via axons to another part of the olfactory system, the olfactory cortex
...

The result is a meaning-laden perception, a gestalt, that is unique to each individual
...
For a rabbit, the same scent may arouse memories of chase and fear of attack
...

But it leaves two important issues unresolved
...
How does the brain recognize that signals from different collections of receptors
all refer to the same stimulus?
Many of our insights were derived from intensive studies of the olfactory bulb
...
In other words, the salient information about the stimulus is carried in
some distinctive pattern of bulbwide activity, not in a small subset of feature-detecting
neurons that are excited only by, say, foxlike scents
...
Such cells continuously receive pulses-usually at projections known
as dendrites-from thousands of other neurons
...
Certain incoming pulses generate excitatory waves of electric
current in the recipients; others generate inhibitory waves
NEURONS OF THE OLFACTORY SYSTEM share information through a rich web of synapses,
junctions where signals flow from neuron to neuron
...


Motivation and the Brain
motivation

• a feeling of enthusiasm, interest, or commitment that
makes somebody want to do something, or something
that causes such a feeling
• reason: a reason for doing something or behaving in a
particular way
• psychological forces determining behavior: the biological,
emotional, cognitive, or social forces that activate and
direct behaviour
...

Using these neuroimaging devices in combination with motivational tests and tasks, researchers now
study motivation in ways unheard of only a decade ago
...
Setting up a system of
rewards, punishments, and reinforcers, psychologists used animals to motivate behaviors in terms of
reaching for rewards or avoiding punishments
...
Ivan Petrovich Pavlov, the Russian
physiologist, psychologist, and physician, studied how dogs salivated when shown food they knew to
be appetizing
...

Dogs could also be conditioned to salivate with a light or tone
...
He called the stimulus a “reinforcer
...
Primary reinforcers motivate behavior without any learning
while secondary reinforcers only motivate after learning – or conditioning - takes place
...
They trained rats to press a lever to obtain food pellets, for
example
...

From these animal experiments, neuroscientists have extrapolated primary and secondary
reinforcers of human behaviors
...
Individuals also quickly learn what elicits negative outcomes,
and try to decrease or avoid behaviors leading to adverse results
...
For instance, in some experimental situations,
humans will make choices to avoid looking stupid
...

The Iowa Gambling Task is one such example, now the most widely used tool for understanding how
humans use rewards and punishments to alter behavior
...
Test participants
select cards from the decks, which, unknown to them, are marked accordingly: two decks are high
risk; two decks are low risk
...

The high-risk decks offer the highest money rewards but also the greatest penalties
...
Over the course
of the game, participants will earn the most and have the lowest amount of penalties by selecting
from the low-risk decks
...
However, test participants with damage or
lesions to the brain’s prefrontal cortex region in the frontal lobes, also called the orbitofrontal cortex
(OFC) because it’s above the eye’ orbits, continue to select from the bad decks
...
However, these results are still
being debated in the scientific community, with many still not convinced in a direct causal link
between OFC dysfunction and consequence planning
...
For instance, some observe only normal
volunteers while others observe those with psychiatric disorders such as schizophrenia and
obsessive-compulsive disorder
...


They have found a way around this limitation by devising studies that activate taste and smell
senses
...

For example, eating one cookie makes you desire another, and another, until after a certain number
of cookies they are no longer appealing
...
The response of the OFC
during the presence of the smells became increasingly reduced, pointing to evidence that the OFC is
involved in the motivation to keep doing something
...
Money is not a primary reinforcer because it does not meet a
physiological need; however, it is a strong motivator of behavior
...


Motivation and Hunger
The nervous system that lines your gut, the enteric nervous system (ENS), is popularly called the “second
brain
...
The ENS manages the body’s digestive system using the same
functional machinery as the brain – a network of neurons, neurotransmitters and proteins
...
The sight of freshly baked pizza stimulates your appetite when it’s mealtime!
Conversely, when we are stuffed after a huge, sumptuous meal, even the mention of food seems nauseating
...
A top-down communication occurs
when hunger is triggered upon an external stimulus (the sight of pizza), and a bottom-up communication is
responsible for the, “I can’t possibly eat anymore” state of mind!
In the 1940s, classic lesion experiments in rats gave rise to a dual center hypothesis for food intake – one
center promotes eating and the other stops eating behavior
...
Lesions in the ventromedial hypothalamus elicited a voracious appetite leading to overeating and an obese phenotype, so this region was labeled the satiety center
...
The same holds true for the obese rat,
which would stop over-eating after a certain set point of high body weight
...


So, what humoral signal makes us hungry? The hormone responsible for arousing hunger in our body is ghrelin
...
It binds to receptors in the
hypothalamus causing the release of orexigenic (appetite-inducing) neuropeptides to enhance food intake
...
After meals,
leptin is released from adipocytes (fat cells) and sends signals to the hypothalamus that the body has enough
energy reserves, so we stop eating! It counteracts the effects of orexigenic neuropeptides and promotes
synthesis of other appetite suppressants
...
Amidst the fanfare of the central nervous system, we forget the quiet actions of the neurons in our
gut
...


Drugs are generally classified as Depressants, Stimulants and Hallucinogens
...
Nerve cells or neurons connect one
area to another via pathways to send and integrate information
...
This pathway is activated when a person
receives positive reinforcement for certain behaviors
...
The thalamus receives information about pain
coming from the body (through the spinal cord pathways and nuclei), and passes the information up
to the cortex
...

Functions affected
• reward (motivation), pleasure, euphoria, motor function (fine tuning), compulsion,
perseveration, decision making
...

Functions affected
• mood, memory processing, sleep, cognition
...

For Opiates, Ethanol, Cannabinoids, Barbiturates, Benzothiazepines, Nicotine- Midbrain and supero
hypothalamic areas affected
...

There is decrease in metabolism in the Orbito Frontal Cortex (OFC)-seen on Positron Emission
Tomography analysis
...

Motor Function is affected to cause

▪

Slowed gait

▪

Impaired balance
...

Implication:
Brain changes resulting from prolonged use of psycho stimulants such as methamphetamine, maybe
reflected in compromised cognitive and motor functioning
...

In the neuropsychological scope, emotions characterize affect as a human response to an event from
the environment that facilitates action for rapid mobilization
...

Emotions and their related facial expression (as part of affective response) are socially adaptive tools
used for communication
...

Recent research has demonstrated that both subcortical and cortical regions of the brain
play important roles in emotional experience and behavior
...
In other words, emotions spontaneously arise and can be
modulated by cognitive assessment of a given situation
...
g
...
But they can also be modulated by our
appraisals of the situation (e
...
, whether or not this person’s characteristics make him or her a good
potential mate)
The emotional factors can be summed up as a set of processes that include attention,
appraisal, perception, and feeling, as well as visceral and motor responses
...
Actions are taken once
a situation has been evaluated
...
g
...

A
...
The hippocampus is important in
furnishing information that is context-specific, framing the emotional interpretation of a specific
stimulus
...

B
...

In the absence of immediately reinforcing incentives, the ventromedial prefrontal cortex is
implicated in representing elementary positive and negative emotional states
...
This is important for both
attentional control and working memory
...
Unpleasant affective
states would be related to the goal of withdrawing from a circumstance that produced the emotion,
and a pleasant experience would be associated with the goal of approaching the circumstance that
produced the emotion
These motivational states of withdrawal or approach have been linked to hemispheric asymmetries
in the prefrontal cortex: right hemisphere activation is associated with withdrawal, and the left
hemisphere is connected with approach
...
Positive feelings
have the reverse pattern, with more activity over the left than the right prefrontal cortex
...

Understanding of emotional information is mediated through the right parietal and temporal regions
of the brain
...


Evidence suggests that the right hemisphere plays an important role in understanding
the emotional meaning of visual information in general
...

The left hemisphere is important for understanding emotion as it links affect to verbal meaning
...
Neurophysiological Substrates of Emotion
Human beings typically experience an emotion as having a component “feeling” often associated
with a physiological experience
...

Numerous neurophysiological systems have been identified in modulating emotion
...

The behavioral component consists of muscle movements appropriate to a given situation (attack or
run if threatened)
...

Hormonal changes support the autonomic response and, are implicated in actions of flight or fight
(emergency)
...

Eg, The adrenal cortex secretes steroid hormones which help to make glucose
available to the muscles
...

Also important to our understanding of neuropsychology of emotion, neurons are
genetically tailored to carry out many functions of the nervous system
...

There are two basic divisions of the nervous
system: the peripheral nervous system (PNS) and the central nervous system (CNS)
...
The PNS is
involved in communicating between the CNS and the glands, sense organs, and the
body (including the intestines, lungs and heart)
...


The ANS has two branches: the sympathetic and parasympathetic nervous systems
...

The sympathetic system is balanced by the parasympathetic system which acts to conserve
body energy and to repair damaged systems and immunological functions
...

V
...
Peptides
consist of a string of amino acids joined together
...
After 200 amino acids, the material is called a
protein
...
Chemical pathways, such as those
involving angiotensin, corticotrophin- releasing hormone (CRH), and oxytocin play a vital role in the
organization of emotion
...
The
amygdala is a major part of the taste/visceral connection to the brainstem
...

Neurons related to emotion, communicate with one another via neurotransmitters
(chemical messengers)
...

Neuromodulators (including estrogen, cortisol, testosterone, and other steroids) regulate
neurotransmitter effects on receptor neurons
...

The monoamines which include serotonin, dopamine, and nonepinephrine also have an
important role in the regulation of emotional and cognitive processing
...
Via the ascending neural network, they are carried
upward through the limbic system to the cortex
...
Too much
dopamine may result in mood changes, increased motor behavior, and frontal lobe functioning that
is disturbed
...
Interestingly, it is believed by many people that schizophrenia is
caused by an excess of dopamine that overloads one’s sensory processing capabilities
...


High levels of norepinephrine may result in vigilance, attacking or defense behavior, and
anxiety
...

Serotonin plays a role in the sleep-wake cycle and arousal and is widely distributed
throughout the brain
...
Serotonin mediates mood
and emotion
...
They also create greater activation of serotonergic neural networks
...
Working together with
neuromodulators, these compounds regulate pleasure, reward systems, and pain
...

Endorphins produced by the body (endogenous endorphins) act as analgesia in conditions of physical
pain
...


Emotions as AN IMPORTANT COMPONENT OF MOTIVATIONAL SYSTEMS
Emotions are an important component of motivvational systems
...

Most mammals possess a core set of emotions—seeking, fear, anger, play, panic, lust, and care
(Panksepp 2005)
...

Below is a brief overview of the core emotional systems
...

The seeking system is the generalized activation system recruited by all vertebrates to organize
the pursuit of food, mates, and shelters
...
Activation of the ventral tegmental area and
nucleus accumbens plays a critical role in causing both approach and aversive action responses
(Ikemoto and Panksepp 1999; Ikemoto 2007; Zellner and Ranaldi 2010)
...
These neurons synthesize endogenous opioid peptide
transmitters such as endorphins and enkephalins, as well as the specialized G protein receptors
for these neurotransmitters
...


Together, the pleasurable experience of an object reinforces the subsequent motivated pursuit of
similar objects
...
It
has a dedicated circuit of excitatory (acetylcholinergic and epinephrinergic) neurons
...
The amydgala plays a key role in distinguishing between aversive
and positive
If the stimulus is deemed dangerous, a cascade of involuntary responses is mediated by nerve
projections to the anterior and medial hypothalamus, on to the periaqueductal gray area (PAG) of
the midbrain, and then to the lower brain stem and spinal cord (Panksepp 2004)
...

The behavioral response to stimulation of these specific subcortical brain areas is freezing,
startling, or fleeing; cognition may be involved in assessing which of several alternative escape
behaviors is best given the current conditions
...

The context and function of the remaining core emotions is the mediation of social interactions
...
The orbital frontal cortex first
processes sensory input from social cues and signals, typically olfactory in the case of rodents
and visual and vocal in the case of primates
...
Pathways then extend to several areas in the
hypothalamus, thalamus, lateral septum, and bed nucleus of the stria terminalis
...
The hypothalamus also connects directly to the pituitary gland, which releases
various hormones directly into the body’s circulatory system that target the adrenal gland
...

As in the fear response, these hormones increase heart rate and blood supply to the muscles
and prepare an animal to fight if necessary
...
In addition, neural pathways from the subcortical ganglia
ascend through the thalamus into the cortex to permit some voluntary control and assessment of
the anger-evoking stimulus
...
Finally, steroid hormones such as
testosterone and estrogen are also necessary to sustain aggressive behavior
...
Testosterone also promotes the

development of aggressive behavioral skills through play behavior in young mammals (Nelson
and Trainor 2007)
...

The opioid and dopamine reward circuits are recruited to motivate play behavior
...

As mentioned above, testosterone is involved: males are more likely to initiate play and respond
to play initiation signals by other males
...
This behavior appears to be initiated
in a region of the cortex called the anterior cingulate
...

This circuit is called the thalamo-cingulate limbic pathway (Herman and Panksepp 1981;
Panksepp 2003b; Newman 2007; Panksepp and Watt 2011)
...
The effects can be modulated
and diminished by the application of various opioid peptides, oxytocin, and the monoamine
neurotransmitter serotonin
...

These peptides are synthesized by specialized cells in the paraventricular nucleus of the
hypothalamus
...
2005), where they operate as neurotransmitters
...

Other cells in the hypothalamus send projections to the nearby pituitary gland, which stores
oxytocin and vasopressin and releases these chemicals into the blood stream, where they
operate as hormones
...
Since these peptides are too large to pass the blood–brain
barrier, their joint physiological and psychological effects are believed to be coordinated by
synchronous release into the brain and circulatory system
...
It increases immediately after birth and
regulates aspects of bonding with infants (Nowak et al
...
A large surge of oxytocin occurs
during sexual behavior and orgasm
...
1994)
...


Some other neurotransmitters also facilitate positive social interactions
...

Opioids are postulated to encourage animals to engage in affiliative social behaviors by inducing
a euphoric state (Nelson and Panksepp 1998)
...

An important message to be extracted from these summaries of the neurophysiological bases of
emotional systems is that each is associated with diagnostic expressions—in other words,
communication signals
...
Fear is associated with screams and fearful expressions; anger with aggressive
postures, staring, weapon presentation, and mouth expressions; and panic with cries and
expressions of pain and sadness
...

Categories of emotions
A final point is the inevitable urge by biologists and psychologists to categorize emotions,
especially in humans, because we have many more described emotions than animals do
...
g
...
1989; Larsen
and Diener 1992; Yik et al
...
Figure 5 shows a melded version of these models
...
The vertical axis is arousal level, and the
horizontal level is pleasantness
...
(After Yik et al
...
)

This type of model was subsequently expanded in several ways
...

Opposing emotions in each pair are situated on opposite sides of the circle, and emotions are
ordered around the circle so that similar emotions are adjacent; the earlier concept of two
orthogonal axes, pleasantness and arousal, was also retained (Diaz et al
...
Another
strategy was to add a third dimension
...


Figure 6: Three-dimensional circumplex model
...
There are four pairs of primary dyads, with the contrasting type on the opposite side

of the circle
...
Colored
regions represent gradations between the primary emotions
...
This model does not reflect the orthogonal pleasantness and arousal
axes of the earlier models
...
)

The most recent models have used multivariate statistical analysis of a large number of variables
describing different emotions, including appraisal, psychophysiological changes, motor
expressions, action tendencies, subjective experiences, and level of emotional regulation and
control to statistically sort out the number of dimensions needed to encompass all of the
emotional terms
...
2005; Fontaine
et al
...
One such model is illustrated in main text Figure 16
...
Although affective
neurobiologists do not find these psychological models helpful, it could turn out to be the case
that the emotional axes do correspond to levels of analysis of emotional contexts in the brain
...
Emotions that
are close to each other on the wheel may use more overlapping components of the neural
circuits, and combination emotions may vary and balance the ratios of different
neurotransmitters
...
2011)
...

Similarly, studies on motivation – specifically conditioned learning – show that some patients with
damage to the amygdala have impairments in conditioned learning concerning both positive and
negative reinforcers
...

Rewards motivate learning, an area of brain circuitry might help turn motivations into memory
...

The research used fMRI to scan the brains of volunteers as they participated in two types of rewardrelated tasks
...
The researchers
showed participants circles or squares that contained an amount of money the subjects could win or
lose
...


Neuroimaging during this task showed increased activity in the mesolimbic brain region as
participants anticipated rewards - an area also associated with emotional processing
...
The scientists showed participants “value” symbols associated with differing scenes
...

The next day the participants returned to pick out scenes from groupings of scenes, and not
surprisingly, the high-value scenes were remembered more than the low-value scenes
...

The hippocampus located in the medial temporal lobe (MTL), is known for higher-order processes
such as learning and memory
...
The study summarized the findings as demonstrating that organisms’ “expectations
and motivation interact with events in the physical world to influence learning
...


LEARNING AND MEMORY

Definitions
According to Eric Kandel (2000) “Learning is the process by which we acquire
knowledge about the world
...
"
According to Kandel (2000), "
...
’’
Learning is a process by which we integrate new knowledge generated as a result
of experiences
...
There is basically no learning without memories
...
One
is declarative or explicit; the other is non-declarative or implicit
...

These things must be recalled into consciousness to be used
...
They can’t remember people that they met the day
before
...

Some people will further parcel explicit memories as episodic (we remember
events) or semantic(we remember facts)
...

IMPLICIT MEMORY

Implicit memory involves information about how to perform something; it’s
recalled unconsciously
...

Eg, I know how to drive my car; I know how to get to work
...
They can learn certain perceptual tasks
...
However, at
the same time, they deny ever having learned the word previously
...

There are two well-known types of non-associative learning: habituation and
sensitization
...
A dog will be aroused when a strange tone is played
...
We
say that it has habituated
...

Sensitization, is an enhanced response to many different stimuli after experiencing
an intense or noxious one
...
Here we say
that the animal is sensitized
...
Once a response has been habituated, it
can be restored by sensitization
...
As an example: a habituated startle response to a noise can be
restored by strongly pinching the skin
...
For example, the dishabituated animal does not learn to
associate the noise with the pinch
...
Not all forms of non-associative learning are as simple as
habituation and sensitization
...
This involves no association of stimuli and is clearly
more complicated than habituation
...

Perhaps important in clinical considerations, a person can also learn that an

outcome is not associated with a response
...

Two sorts of associative learning have been well studied:classical
conditioning and operant conditioning
...
He repeated the presentation, and each time the dog
salivated
...
In fact, for a
while it would salivate if the bell was rung but no meat powder was presented
(they were unpaired)
...
(This process
is called extinction
...
5 sec)
...

In Pavlov’s paradigm, the meat powder normally elicits salivation without
experimenter intervention (it is innate or perhaps previously strongly learned), and
it is called the unconditioned stimulus (US)
...
The bell comes to elicit salivation only after it is
repeatedly paired with meat powder; so it’s called the conditioned stimulus (CS)
...
The
UR and the CR are usually similar but often not identical in type or strength
...
Now we think that what the animals learn is contingencies–that
existence of something depends upon existence of something else
...
On the other hand, the existence
of superstitious behaviors, even in humans, suggests that this does occur
...

The difference is that something new is learned during the process of extinction–
the animal learns that the CS is no longer a signal that the US is about to occur,
rather it is a signal that the US will not occur
...
So, a pigeon learns that it gets food if it pecks at a certain key, but not

if it pecks at another
...
Presumably what the animal learns is that one of its
many behaviors (pecking or bar pressing) is followed by food
...


Neuroscience of Learning and Memory
We want to know about what is going on in the brain when a person or animal
learns something, stores what has been learned and later retrieves it for use in
behavior
...
[18] It was in fact shown that activity at a synapse leads to structural
changes at the synapse and to enhanced firing in the postsynaptic neuron
...

During this process existing synaptic proteins are altered and new proteins are synthesized at
the modified synapse
...
Donald Hebb found out
that not only a synapse of two neurons is involved in LTP but that a particular group of neurons is
more likely to fire together
...
So it works according to the principle: “what wires together fires together”
...


Following any learning event, the Long Term Memory for the event is not instantaneously
formed
...
During the consolidation period, memory can be modulated
...

Greater emotional arousal following a learning event enhances a person's retention of that event
...

The amygdala, especially the basolateral nuclei, is involved in mediating the effects of emotional
arousal on the strength of the memory for the event
...
These laboratories have trained animals
on a variety of learning tasks and found that drugs injected into the amygdala after training affect
the animal’s subsequent retention of the task
...
If a drug that activates the amygdala is injected into the amygdala, the animals had better
memory for the training in the task
...
Despite the importance of the amygdala in
modulating memory consolidation, however, learning can occur without it, although such learning
appears to be impaired, as in fear conditioning impairments following amygdala damage
...
Amygdala
activity at the time of encoding information correlates with retention for that information
...
More emotionallyarousing information increases amygdalar activity, and that activity correlates with retention
...


Some researchers prefer to consider the hippocampus as part of a larger medial temporal
lobe memory system responsible for general declarative memory (memories that can be explicitly
verbalized — these would include, for example, memory for facts in addition to episodic
memory)
...
Damage to the hippocampus usually results in profound difficulties in
forming new memories (anterograde amnesia), and normally also affects access to memories
prior to the damage (retrograde amnesia)
...
However, researchers have difficulties in
testing the sparing of older memories and, in some cases of retrograde amnesia, the sparing
appears to affect memories formed decades before the damage to the hippocampus occurred,
so its role in maintaining these older memories remains controversial
...


This figure shows the brain structures which are involved in forming new memories

Then, the information is transferred to parahippocampal and perirhinal cortices,
entorhinal cortex dentate gyrus, hippocampus, subiculum and back to entorhinal,
parahi
ppoca
mpal
and
perirhi
nal
cortex
...
18-1 - The relative positions of parts of the limbic system involved in learning and
in
memory
...
New
differe York: McGraw-Hill
...
Damage to parahippocampal, perirhinal and entorhinal cortices produces

greater deficits in memory storage for object recognition than does hippocampal
damage
...
In either case, the deficits are in formation
of new, long-term memory; old memories are spared
...
18-2 - The relative positions of parts of the limbic system involved in learning and memory
...
New York: McGraw-Hill
...
The results of hippocampal machinations–presumably memories–are
transferred to the association cortex for storage
...
This make sense when it is recalled that a
single memory has multiple facets–each event contains sounds, smells, tastes,
somatosensory experiences, visual images and so forth
...

So, each new explicit memory is formed by four sequential processes:
Encoding-information for each memory is assembled from the different
sensory systems and translated into whatever form necessary to be
remembered
...


Consolidation-converting the encoded information into a form that can be
permanently stored
...

Storage-the actual deposition of the memories into the final resting places–
this is though to be in association cortex
...

Less is known about this process
...

“Fear conditioning” (training that involves use of fearful stimuli) involves the
amygdala
...
For
example, eye blink conditioning is disrupted by lesions of the dentate and
interpositus nuclei of the cerebellum
...
Perhaps surprisingly, certain simple reflexes
mediated by the spinal cord can be classically conditioned even after the cord has
been surgically isolated from the brain
...

STAGES OF MEMORY PROCESSING
Sensory memory
Sensory memory holds sensory information for less than one second after an item is perceived
...
It is out of cognitive control and is an automatic
response
...
The first experiments exploring this form of sensory memory were
conducted by George Sperling (1963)[1] using the "partial report paradigm"
...
After a brief presentation,
subjects were then played either a high, medium or low tone, cuing them which of the rows to
report
...
Because this form of memory degrades so quickly, participants would see the
display but be unable to report all of the items (12 in the "whole report" procedure) before they
decayed
...


Three types of sensory memories exist
...
Echoic memory is a fast decaying store of auditory information, another type of sensory

memory that briefly stores sounds that have been perceived for short durations
...


Short-term memory
Short-term memory allows recall for a period of several seconds to a minute without rehearsal
...
Miller (1956), when working at Bell Laboratories, conducted
experiments showing that the store of short-term memory was 7±2 items (the title of his famous
paper, "The magical number 7±2")
...
[4] For example, in recalling a ten-digit telephone number, a person could
chunk the digits into three groups: first, the area code (such as 123), then a three-digit chunk (456)
and lastly a four-digit chunk (7890)
...
This may be reflected in some countries in the
tendency to display telephone numbers as several chunks of two to four numbers
...
Conrad (1964)[5] found that test subjects had more difficulty recalling
collections of letters that were acoustically similar (e
...
E, P, D)
...

Conrad's (1964) study, however, deals with the encoding of written text; thus, while memory of
written language may rely on acoustic components, generalisations to all forms of memory cannot
be made
...
By contrast, long-term memory
can store much larger quantities of information for potentially unlimited duration (sometimes a
whole life span)
...
For example, given a random seven-digit number
we may remember it for only a few seconds before forgetting, suggesting it was stored in our shortterm memory
...


Short-term memory is supported by transient patterns of neuronal communication, dependent on
regions of the frontal lobe (especially dorsolateral prefrontal cortex) and the parietal lobe
...
The hippocampus is essential (for learning new
information) to the consolidation of information from short-term to long-term memory, although it

does not seem to store information itself
...
Furthermore, it may be involved in
changing neural connections for a period of three months or more after the initial learning
...
In such a circuit, one neuron
excites another and the other excites the one such that, once the
circuit is activated, action potentials run around continuously
...
18-3
...
If this kind of arrangement accounts for memory, then
any event that temporarily stopped activity in the circuit should
disrupt memory
...


Fig
...
(Kandel,
ER, JH Schwartz
and TM Jessell
(2000) Principles
of Neural Science
...
)

Some years ago, the psychologist Donald Hebb (Hebb, DO (1949) The
Organization of Behavior: A Neuropsychological Theory
...
Briefly, the principle is “When an axon of cell A
...
” As we shall see, current thought is an extension of
Hebb’s rule
...
Their
results are shown
schematically in Fig
...
If the siphon of
the animal is
stimulated
mechanically the
animal withdraws the
gill, presumably for
protection
...
18-4 - Simplified neural circuits involved in the habituation process
interneuron, the
inAplysia
...
They synapse on 6 motor neurons that innervate the gill and
various interneurons as shown
...

the habituated condition on the right
...
New York: McGraw-Hill
...
All of
this is shown on the
left side of the figure
...
There appears to be no change in the sensitivity of postsynaptic
NMDA or non-NMDA receptors
...
It is presumed that habituation in vertebrates, including man,
occurs by a similar process
...
An
example, again taken from experiments in Aplysia, is shown below
...
If the tail of the animal is
stimulated just before the siphon is, then the withdrawal of the gill is quicker and
more forceful
...

As shown in the figure, activation of the sensory receptors in the tail activates,
through sensory neuron 2, a facilitating interneuron that excites sensory neuron 1
in the pathway leading the gill withdrawal
...

The consequence of the sensitization process is to increase the size of the EPSP in
the motoneuron without increasing the response of sensory neuron 1
...
18-5 - Sensitization is produced by applying a noxious stimulus to the tail of the Aplysia's tail,
activated sensory neuron 2
...
(Kandel, ER, JH Schwartz and
TM Jessell (2000)Principles of Neural Science
...
)

the gill
...
However, the sensitization can be made relatively
permanent by repeated tail stimulation
...
With sensitization, there is an up to 2-fold increase in the number of
synaptic terminals in both sensory and motoneurons
...


LEARNING ACC TO HEBB
Hebb proposes that whenever conditioned reflexes are established in an organism through
learning, a new anatomical substratum is established in the brain through a physiological process
in which weak or non-existent synapses are strengthened by biochemical modification or by
permanent changes in their electrical properties
...


Hebbian theory is a theory in neuroscience that proposes an explanation for the adaptation of
neurons in the brain during the learning process
...

Hebb states it as follows:
"Let us assume that the persistence or repetition of a reverberatory activity (or "trace") tends to
induce lasting cellular changes that add to its stability
...
"

The theory is often summarized as "Cells that fire together, wire together’’
...
Synapse is a part of neural cell
structure that is believed to store the newly acquired neural network function
...

Mirror neurons are neurons that fire both when an individual performs an action and when the
individual sees or hears another perform a similar action
...
The activation of these motor programs then adds information to the perception and
help predict what the person will do next based on the perceiver's own motor program
...
These re-afferent sensory signals
will trigger activity in neurons responding to the sight, sound and feel of the action
...

The same is true while people look at themselves in the mirror, hear themselves babble or are
imitated by others
...

Evidence for that perspective comes from many experiments that show that motor programs can be
triggered by novel auditory or visual stimuli after repeated pairing of the stimulus with the execution
of the motor program (see [13] for a review of the evidence)
...
Five hours of piano lessons, in which the participant is exposed to the sound of the piano
each time he presses a key, suffices to later trigger activity in motor regions of the brain upon
listening to piano music
...
When neurons fire together, they
wire together
...

Understanding Synaptic Plasticity
A considerable amount of brain research has been produced on learning and memorization over
the last decade
...
Early studies on learning used electrical
stimulation within the hippocampal formation, a brain structure known to play a critical role in
memory formation
...
The discovery of LPT proved what Donald Hebb (1949) suggested over 50
years ago while trying to describe a law that would explain the process by which we remember in
our brain
...
More recent research reveals that the
process of LPT is largely governed by chemical reactions between important receptors such as
NMDA and AMPA receptors
...

The study of structural changes in the brain as a result of learning and memorization has
received a considerable boost since neuroscientists have used imaging technology such as fMRI
in the mid 90s
...
For instance,
research conducted by Bogdan Draganski and his colleagues of the Department of Neurology of
the University of Regensbug Germany (Draganski &, 2006) demonstrated that gray matter volume
increases as a result of learning
...

Though it is still very difficult for Neuroscientists to crack the neural code of both learning and
memory, we do know that the production of new neurons is primarily possible in the
hypothalamus, the brain area mostly responsible for creating and maintaining our long term
memories
...


Long-term Potentiation
As previously detailed, the hippocampus is important in storage of declarative
memory
...
Since then the same phenomenon has been

observed in various other places known to be involved in memory storage
...

A high-frequency train of stimuli applied to fibers afferent to the hippocampus
increase the amplitude of EPSPs in the target neurons
...
This property
has been termed cooperativity
...

This latter property has been termed associativity
...


Fig
...
(Kandel, ER, JH
Schwartz and TM Jessell (2000) Principles of Neural Science
...
)

By contrast, during the early phase of LTP, the high-frequency stimulation opens
glutamate channels leading to hypopolarization
...
The calcium
triggers the activity that increases sensitivity to glutamate and a messenger is sent
to the presynaptic terminal to increase the release of transmitter substance
...


In the late phase of LTP, calcium enters the cell and activates the nucleus of the
cell and starts processes that lead to protein synthesis and to structural changes,
i
...
, the formation of new synapses
...

There are still unanswered questions about the relationship of LTP to memory
...
How long LTP can be maintained is difficult to determine
...
Still
memories may last much longer
...
What is not known is whether disruption of LTP
also interferes with memory
...
This kind of memory involves a number of processes: habituation involves
decrease in synaptic strength from decreased transmitter release; sensitization involves
increase in synaptic strength due to presynaptic facilitation; and classical conditioning
involves increase in synaptic strength due to presynaptic facilitation that is dependent on
activity in both pre- and postsynaptic cells
...
This kind of memory probably makes use of long-term potentiation
...
In the late phase of LTP, protein synthesis leads to changes in cell structure and
formation of new synapses
...
To show what effects memory diseases can have and
how they are classified, we will discuss a case study of amnesia and two other common
examples for amnesic diseases: Karsakoff’s amnesia and Alzheimer’s disease
...


Different types of Amnesia

Amnesia can occur when there is damage to a number of regions in the medial temporal lobe
and their surrounding structures
...
M
...
Removing his medial temporal lobes, including the hippocampus,
seemed to be a good way to treat the epilepsy
...
M
...
So given the definitions above one can say that he suffered
retrograde amnesia
...
H
...
therefore suffered not only from retrograde amnesia,
but also from anterograde amnesia
...
In
procedural memory tests, for example, he still performed well
...
But after some weeks his performance improved even though he
could not remember having done the task many times before
...
M
...
Another quite common cause of
amnesia is the Korsakoff’s syndrome or also called Korsakoff’s amnesia
...
This
syndrome is associated with the pathology of the midline diencephalon including the dorsomedial
thalamus
...
Over 40 percent of the people who are older than 80 are
affected by Alzheimer’s disease
...
This cortex forms the main input and output of the
hippocampus and so damages here are mostly severe
...
But in late stages of Alzheimer’s disease also retrograde amnesia
and even other cognitive abilities, which we are not going to discuss here, might occur
...
These researchers used an animal with a very
simple neural net, the sea slug Aplysia californica, for their studies
...
The
neural pathways responsible for this behavior are well understood, as are the effects of learning on
this behavior
...

Habituation

Habituation means that repeated stimulation leads to a decreased response
...
In the short-term,
the weaker responses can be explained by depletion of available neurotransmitter
...
These longer-lasting changes probably
involve changes in postsynaptic glutamate receptors, or receptors on the receiving motor neuron
responsible for withdrawal
...


Long-term changes in the number of sensory axon terminals occur in habituation
...

Sensitization

Sensitization refers to a heightened response that results from exposure to a strong stimulus
...


In Aplysia, sensitization is demonstrated by first shocking the head or tail of the animal, and then
observing the strength of a gill withdrawal reflex in response to touch
...


The underlying mechanisms for sensitization are more complicated than we saw in habituation
...


1
...
Interneurons have neither specific sensory nor motor functions, but often form
bridges between sensory and motor neurons
...
These interneurons form synapses with the axons of sensory neurons serving the siphon, or "axoaxonic" synapses
...
As a result, any action potentials in the siphon sensory neuron resulting from touch last
longer than normal
...
With longer action potentials, more calcium enters the sensory neuron, which then releases more
neurotransmitter than normal onto the motor neurons responsible for the gill withdrawal
...
Trained animals had 2800 terminals compared with 1300 for untrained animals
...

Sensitization training increases the number of the animals' AMPA glutamate receptors
...


Before any training, touching the mantle shelf (conditioned stimulus) does not produce much
movement of the gill
...


Let's trace the changes that must take place for this learning to occur:

1
...
As a result,
neurotransmitters are released onto the motor neurons controlling the gill withdrawal
...
When the tail is shocked soon after the mantle shelf is touched, sensory neurons from the tail
activates interneurons, which form synapses on the axon terminals of the sensory neurons serving
the mantle shelf
...


3
...


As was the case with sensitization and habituation, postsynaptic changes resulting from classical
conditioning training also contribute to the long-lasting nature of this type of learning
...


What is consciousness?
•

Posted by Christophe Morin - SalesBrain on October 18, 2009 at 7:30pm

•

View Blog

For centuries, philosophers and scientists have researched the nature of consciousness
...
For

Descartes, the soul was produced outside of our physical body even though he suggested that it
might actually reside inside the brain
...
For him, the soul simply could not reside in a split brain area
...
Dualism continues to
influence many thinkers even today
...
Most recently, however, advances in brain science have helped elevate this heated dialogue
beyond just rhetoric or ideology
...
But to make things more difficult,
the term consciousness itself has been the subject of ongoing discord
...
Moreover, consciousness is used or considered a substitute for
many other words that are as abstract and ambiguous as the term itself
...
Clearly, the debate on the nature
of consciousness is not going to end anytime soon if we continue to struggle with the adoption
of a clear and operational definition
...
Since consciousness is now widely recognized to be directly tied to the
existence of states produced by the brain, it seems reasonable to adopt a definition that comes
from the field of cognitive neuroscience
...
Awareness becomes a key factor in a****sing the quality of
such states since it varies greatly based on the relevance or attractiveness of an event, the
attention committed to such events, and finally, to our ability to maintain wakefulness during any
event
...
Finally, it is important to note that
states of consciousness have been measured and identified as representative of certain patterns
of neurons firing within the brain confirming that consciousness itself is intimately related to
neuronal activity
...
Let’s review now the factors most responsible for how we
become conscious: experience, attention and wakefulness
...
Experience is intimately influenced by prior beliefs encoded as memories in our brains
...
The more relevant an event is to us, the more conscious our experience of it appears to be
...
Work
conducted by Richard Davidson (1990) shows that emotions guide our actions and mediate the

way we face experience
...
Conscious experience expands or augments the immediate sensations we
are able to perceive at any given moment
...
This area is most responsible for producing self-thoughts, an activity
directly linked to our ability to develop self-consciousness (Gazzaniga, 2009, p
...
This
strongly suggests that our level of consciousness is indeed related to how much we assign value
or relevance to a given experience
...
We are indeed largely influenced by what is
referred to as subjective awareness
...
It is only accessible to the
individual and not to an observer
...

The term qualia is often used to describe the subjective quality of our awareness
...
However, scientists remain unmoved by the philosophical argument and continue to
research ways to map or measure manifestations of any kind of awareness including, from
objective to subjective
...
For instance, it is well known that many
functions in the brain including decision-making show great latency between the time when
cortical or subcortical activity can be recorded and when the decision is actually made (Libet,
2006), presumably because many cortical functions such as visual processing happen in just a
few milliseconds
...
We can control some of our attention willingly, which
is known as selective or voluntary attention
...
This is referred to as reflexive attention
...
The speed at which we need to react correlates highly with the degree to which
we control our attention willingly
...
The PFC is highly involved in using selective attention whereas reflective attention is
directly managed by the brain stem and the limbic system
...
Also, both the lateral geniculate nucleus (LGN) and the pulvinar nucleus of
the thalamus play a significant role in mediating attention
...
Covert attention describes the ability to take notice of information in the
periphery of the object or space in which we are placing our attention
...


Wakefulness (Sleep to Awake)
Though it is not clear why we sleep, we do know that we can seriously impair brain functioning
or even die as a result of lack of sleep
...

Brain activity varies during the day
...
These waves have the
highest number of cycles of minutes of any awake state and shows desynchrony in the brain
...
The deeper we fall asleep or the less conscious we become, the more
synchronous the brain waves become suggesting that the brain is firing less during cognitive
functions
...
It is during the REM sleep stage that we
dream, which is yet another state of consciousness that has fascinated humans for thousands of
years
...
As a result, lucid dreamers may reclaim
the power to move their body with increased consciousness
...
We can also infer
that consciousness is not produced by external stimulation alone
...
Since brain scientists are
just beginning to map neural activity that correlates with many of those states, the study of
consciousness is rapidly evolving
...
A thin layer of gray
matter called the claustrum receives input from almost all regions of the cortex and projects
back to almost all regions of the cortex making it a good candidate for being the center of
consciousness

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