Transcript PowerPoint Presentation - Sperry`s Split Brain Studies

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Our Brains are made in a way that allows it to
adapt to the environment that it is placed in.
Neurotransmission and hormones adapt to the
specific environment it is placed in. This is has
been shown in research dealing with adaptation
to violent environments and neurotransmission
desensitization.
Research should be used to support your
explanation.
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Early 20th century: believed that brain was only
influenced by genes and thus unchangeable
Now we know that environmental enrichment
/deprivation(an environmental factor) can
modify the brain (a physiological process).
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The effect of Deprivation and Stimulation on
Neuroplasticity
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Neuroplasticity is a non-specific neuroscience
term referring to the ability of the brain and
nervous system in all species to change
structurally and functionally as a result of input
from the environment
Plasticity occurs on a variety of levels, ranging
from cellular changes involved in learning, to
large-scale changes involved in cortical
remapping in response to injury and disease.
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Neuroplasticity is a non-specific neuroscience
term referring to the ability of the brain and
nervous system in all species to change
structurally and functionally as a result of input
from the environment
Plasticity occurs on a variety of levels, ranging
from cellular changes involved in learning, to
large-scale changes involved in cortical
remapping in response to injury and disease.
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Neurons can compensate for injury or disease or
to adjust their activities in response to new
situations or changes in the environment. The
brain is most plastic early in life (This is known as
the critical period).
The brain can rearrange the connections
between neurons (dendritic branching)
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The brain can generate new neurons throughout
life (neurogenesis)
Learning can increase/decrease
neurotransmission between specific neurons (long
term potentiation)
It is assumed that as your behavior changes (in
most cases because of environmental change),
so does the underlying neural circuitry.
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Environmental enrichment concerns how the brain is
affected by the stimulation of its information
processing provided by its surroundings (including the
opportunity to interact socially).
 Brains in richer, more stimulating environments, have
increased numbers of synapses, and the dendrite
arbors upon which they reside are more complex.
 This effect happens particularly during
neurodevelopment, but also to a lesser degree in
adulthood.
What does this suggest?
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Aim: To investigate the effect of enrichment
or deprivation on the development of
neurons in the cerebral cortex in rats
Research method: Experiment
Procedure: Rats were placed in either a
stimulating environment (toys) or a
deprived environment (no toys).
The rats spent 30 or 60 days in their
environment and then they were dissected.
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Findings: Post mortem
studies of the rats´
brains showed that
those that had been in a
stimulating environment
had an increased
thickness in the cortex.
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Aim: To investigate if stimulating
environments affect the growth of neurons in
rats
Research method: Experiment
Procedure: Rats were placed in enriched
environments beginning at weaning or as
young adults. Control group were placed in
standard cages
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Findings: Both age
groups raised in
enriched
environments
showed a large
increase of the
length of dendrites
in cortical neurons.
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According to the principle that states animal
research can be used in place of human because
of their biological similarities, we can infer that a
lack of stimulation (deprivation—such as in oldstyle orphanages) delays and impairs
physiological parts of the brain responsible for
cognitive development.
Research also finds that higher levels of education
(which is both cognitively stimulating in itself, and
associates with people engaging in more
challenging cognitive activities) results in greater
resilience (cognitive reserve) to the effects of
aging and dementia.
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Such studies suggest that brains are physically
sculpted by our environments. Aspects of the brain
can be changed as we go through experiences. As a
person develops a greater number of skills and
abilities, the brain actually becomes more complex
and heavier.
Research has also suggested that Children who are
unable to have certain experiences, will have specific
parts of their brain significantly less developed, less
intricate, and thinner in comparison to those who
have had those experiences.
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Another way in which the brain and environment
interact is through the activity of the recently
discovered mirror neurons. Mirror neurons are
neurons that fire when an animal performs an
action or when the animal observes somebody
else perform the same action.
This means we subconsciously mimic the actions
of others and thus share, to some extent, their
experience.
How can this be effected by your environment?
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http://www.ted.com/talks/vs_ramachandran_the_n
eurons_that_shaped_civilization.html
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The proposed mechanism is rather simple. Each
time an individual sees an action done by another
individual, neurons that represent that action are
activated in the observer’s premotor cortex.
This automatically induced, motor representation
of the observed action corresponds to that which
is spontaneously generated during active action
and whose outcome is known to the acting
individual.
Thus, the mirror-neuron system transforms visual
information into knowledge.
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These mirror neurons, as they are known, also
allow us to know what another person is feeling,
without having to think about it.
The discovery of mirror neurons is among the most
significant neuroscientific discoveries in recent
years.
This mean that when you see someone doing
something, in your brain you do it too - for
instance, when you watch a person running, the
bit of your brain concerned with planning to move
the legs is activated.
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When you see another person expressing an
emotion, the areas of your brain associated with
feeling that emotion are also activated, making
emotions transmittable.
Emotion mirroring is thought to be the basis of
empathy. Autistic people often lack empathy and
have been found to show less mirror-neuron
activity.
Mirror neurons explain why emotion is whipped up
in horror film audiences - seeing someone else
looking frightened makes you feel scared yourself.
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http://www.robotcub.org/misc/papers/06_Rizzolat
ti_Craighero.pdf
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There are numerous theories/studies that suggest
that our cognition(to mean such functions or
processes as perception, introspection, memory,
creativity, imagination, conception, belief,
reasoning, volition, and emotion) interacts with
physiological functions (brain parts,
neurotransmitters) to guide behavior.
This essay should be started by first explaining the
interaction between physiology and cognition in all
behavior. Examples should be provided to show
knowledge and understanding of these interactions.
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In psychology, cognition is a group of mental
processes that includes attention, memory,
producing and understanding language,
perception, and making decisions.
There is an interaction of physiological factors
and cognitive factors in many of the behaviors
that we experience.
One particular behavior is the experience of
emotion.
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Psychologists have long debated the role
physiological, and cognitive factors play in
emotions.
Originally believed to be a physiological
experience, research now suggests that
emotions are an interaction of both
physiological and cognitive factors.
Different theories debate the role and primacy
of each. For this objective, we will evaluate two
theories.
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Emotions are an individual’s subjective feelings
and moods.
The term applies to both physiological and
cognitive responses to specific stimulus situations.
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One component of emotions is cognitive
processes.
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Although psychologists differ in the extent to
which they emphasize the role of cognition in
emotional arousal and expression, there is a
general consensus that perception, learning, and
memory are all very much involved in
experiencing emotions.
Listening to music, or looking at a picture often
elicits conditioned or learned emotions.
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The other component of emotions is physiological arousal.
When
someone describes their anger by saying “the juices
were flowing,” this account is close to the mark.
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“juices," in the form of epinephrine and other hormones
associated with the arousal of anger, probably were flowing.
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a result of this increased endocrine activity, we might
guess that for a few moments the heart rate increases
dramatically, blood pressure probably increased significantly,
and breathing may have become rapid and uneven.
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other words, there is a physiological response to our
emotions.
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Schacter (1964) was the first theorist
to bring together the two elements of
physiological arousal and cognition.
It is sometimes known as the twofactor theory of emotion. For an
emotion to be experienced, a
physiological state of arousal is
necessary AND situational factors
will then determine how we
perceive this arousal.
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In other words, an event causes physiological
arousal first.
You must then identify a reason for this arousal
and then you are able to experience and label
the emotion.
The strength of physiological arousal will
determine the strength of emotion experienced,
while the situation will determine the type of
emotion. These two factors are independent of
each other BUT both are necessary for the
emotion to be experienced.
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We appraise the emotion-causing event while
also evaluating what is happening with our
bodies. The key process in emotional arousal is
how we interpret feedback from our bodies in
light of our present situation.
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So, imagine you are alone in a dark
parking lot walking toward your car. A
strange man suddenly emerges from a
nearby row of trees and rapidly
approaches.
The sequence that follows, according
to the two-factor theory, would be
much like this:
1. I see a strange man walking toward me.
2. My heart is racing and I am trembling.
3. My rapid heart rate and trembling are
interpreted as fear because of the
situation.
4. I am frightened!
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Why are cognitive labels important in identifying
emotions?
How can this same physiological response be
perceived differently?
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Physiological responses related to the
emotions of fear, anger, love, and jealousy are
very similar. Without a cognitive label, we
would misinterpret those emotions.
M. Grecco/ Stock Boston
Excitement and fear involve a similar
physiological arousal.
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Schachter and Singer’s Experiment
A classic study by Schacter & Singer ( 1962)
supports these ideas. Their study tested the theory
that an emotion is made up of cognitive appraisal
(labeling the emotion) and physiological arousal
(adrenaline and the physical changes it produces).
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Schachter and Singer’s Experiment
The aim of the experiment was to test the twofactor theory of emotion to see if participants
exhibited both cognitive and biological reactions
to an stimulus.
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Schachter and Singer’s Experiment
A
group of 184 male participants were injected with
epinephrine, a neurotransmitter (which also doubles as
a hormone) that produces arousal including increased
heartbeat, trembling and rapid breathing.
All
of the participants were told that they were being
injected with a new drug to test their eyesight (which
was false). However, one group of participants were
informed of the symptoms the injection might cause
(control group), while other participants were not
(experimental group).
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Schachter and Singer’s Experiment
Participants
were then placed in a room with
another participant who was actually a
confederate in the experiment.
The
confederate either acted in one of two ways:
euphoric or angry. Participants who had not been
informed about the effects of the injection were
more likely to feel either happier or angrier than
those who had been informed.
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While Schachter and Singer’s research spawned a great
deal of further research, their theory has also been
subject to criticism. Other researchers have only partially
supported the findings of the original study, and have
had times shown contradictory results.
Other criticisms of the two-factor theory:
Sometimes emotions are experienced automatically
before we have time to perceive them.
The sample was not representative (all male) and males
may have different emotional reactions to females. This
therefore makes it difficult to generalize the findings
further.
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You need to be able to explain these
technologies, what they are used for, and their
relative use at the biological level.
You also need to give examples of research that
use these technologies to demonstrate your
knowledge and understanding of each
technique.
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Scientists who studied brain properties and
functions many years ago were forced to
experiment on animal brains, to study autopsied
brains (post mortem) of people who had various
cognitive and/or motor impairments, and to
compare the behavior of people with normal
and abnormal brains.
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Recent advances in computerized imaging technology
have made it possible to non-invasively pass through
the skull and brain tissue and observe, amplify, record,
rapidly analyze the brain substances and signals that
reflect activity in very specific brain regions.
This technology has revolutionized brain and mind
research, and the diagnosis and treatment of many
brain-related diseases and malfunctions.
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Electroencephalogram (EEG)
 Magnetic Resonance Imaging (MRI)
 Positron Emission Tomography (PET)
scan
 Functional Magnetic Resonance
Imaging (fMRI)
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An amplified recording of the electrical waves sweeping
across the brain’s surface, measured by electrodes placed
on the scalp.
AJ Photo/ Photo Researchers, Inc.
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The electroencephalogram (EEG) is a
recording of the electrical activity of
the brain from the scalp.
The first recordings were made by
Hans Berger in 1929 although similar
studies had been carried out in
animals as early as 1870.
The waveforms recorded are thought
to reflect the activity of the surface of
the brain, the cortex. This activity is
influenced by the electrical activity
(neurotransmission) from the brain
structures underneath the cortex.
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EEG has been employed clinically for some time
as a measure of brain function in the hope of
determining and differentiating certain functional
conditions of the brain.
 It is used in patients with cognitive dysfunction
(due to low neurological activity and or brain
damage), either a general decline of overall brain
function or a localized deficit.
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EEG is used extensively to assess neurological
disorders.
Abnormal decreases of brain activity, usually
associated with large slow EEG waves, can occur
with brain damage.
After very extensive brain damage there may be
no electrical activity recorded from the brain.
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The EEG patterns change when external stimuli (such
as sounds or pictures) are presented. These stimuli
cause or evoke a particular pattern of brain activity,
called the evoked potential.
When we measure a lack of activity during a certain
activity, we are able to conclude that lower levels of
neurotransmission are taking place in that region of
the brain.
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A
more revealing look at the brain is obtained by
brain-imaging techniques, which provide pictures or
scans of the brain.
One
such technique is the computerized axial
tomograph (CAT) scan. A CAT scan takes thousands
of X-ray photographs of the brain while the patient lies
still on a table. The patient’s head is placed in the
middle of a doughnut-shaped ring.
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Using
a computer, the multiple X-ray
images are combined to construct a
picture of the brain.
How can seeing an actual picture of the
brain be beneficial to psychologist at the
BLOA?
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CAT scans are helpful in
detecting brain abnormalities,
such as swelling and lesions in
certain areas.
Based on this cat scan, what
part of the brain appears to
be “abnormal”?
What can we assume about
the behavior of this patient
based on the cat scan?
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With cat scans (as well as MRI scans) we are
better able to understand localization of
function in live humans.
The patient in the picture suffered from
cerebral contusions. This brain damage had a
cognitive effect on coordination and
movement. They also had difficulty with
making sense of memory, managing
emotions, and thinking.
Thus, we are able to better understand the
human brain without the necessity of postmortem studies.
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Another brain-imaging technique is magnetic
resonance imaging (MRI).
This technology produces three-dimensional
images of the brain’s soft tissues by detecting
magnetic activity from nuclear particles in
brain molecules.
MRI provides greater accuracy in the
diagnosis of brain diseases than the CAT scan.
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Magnetic
Resonance Imaging (MRI) has been in
widespread use since the early 1980s.
It uses magnetic fields , radio waves and
computerized enhancement to map out brain
structure. MRI scans provide better images of
brain structure than CAT scans.
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Doctors
often recommend magnetic resonance
imaging (MRI) when investigating whether a
person has Alzheimer's disease, mainly to rule
out other possible causes for cognitive
impairment, such as a brain tumor or blood clot.
But recent research suggests that MRI could
become a key diagnostic tool by revealing
changes in the brain even before Alzheimer's
symptoms appear.
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Alzheimer's
disease affects the brain in many
ways, but one of the most apparent involves an
area called the hippocampus.
This part of the brain is responsible for memory
and processing emotion; it also plays a role in an
individual's motor skills.
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In
a small 2008 French study, researchers using
MRI to evaluate people with Alzheimer's disease
found that the hippocampus in those already
diagnosed was nearly a third smaller than
average.
The hippocampus was 19% smaller in people
who had not been diagnosed but were
experiencing mental impairment.
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In
the aforementioned study, which involved 74
subjects, physicians reported being able to
classify those with Alzheimer's disease and those
without symptoms with 84% accuracy based on
measurement of the hippocampus.
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researchers were accurate 73% of the time
when distinguishing between patients without
symptoms and those with mild cognitive
impairment. Again, however, it's important to
remember that this was a small study.
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This
would suggest that MRI scans, when done
early on in life, can help to predict and diagnose
cognitive disorders such as Alzheimer's and
dementia that directly effect specific parts of
the brain.
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The
positron emission tomography (PET) scan
measures the amount of brain activity.
Neural activity in different brain regions is
measured by showing each region’s use of
glucose, a sugar that is the brain’s chemical fuel.
PET scans can reveal which parts of the brain
are most active in such tasks as talking or
listening to others, reading, listening to music,
and solving math problems.
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A
newer technology called functional magnetic
resonance imaging (fMRI) produces a picture of
neural activity averaged over seconds, not
minutes, and the images can identify much
smaller brain structures than those in PET scans.
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Questions?
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