Transcript File - firestone falcons

THE BIOLOGICAL
PERSPECTIVE
BIOLOGICAL PERSPECTIVE
Linking the introspective study of consciousness
(what you are thinking and feeling based on
mental self-report)
With what is happening at the biological level?
(brain activity at different sites and changes in
chemical messengers)
METHODOLOGIES
Correlational Studies
Experiments
Observations
Case Studies
BRAIN/BEHAVIOR LINK
Our ancestors understood that the brain and behavior
are linked.
For example a strong blow to the head can result in:
A change of consciousness
A change in perception
Memory loss
Loss of movement
TREPANATION
40,000 –year-old skulls show
evidence that parts of the skull
were deliberately removed.
May have been a medical
treatment or to release evil
spirits.
Sometimes practices by tribal
groups in “religious”
ceremonies.
The presence of trepanated
skulls does suggest an
awareness of the link between
brain and behavior.
CORRELATIONAL STUDIES
Psychologists investigate the relationship between the
brain and behavior by examining what happens after the
brain is damaged – either accidentally or deliberately as
part of an experiment
Examples include: stroke, epileptic seizure or head injury
Studies are correlational because changes in behavior
are assumed to be related to brain damage
OBSERVATIONS
An alternative way of studying brain function is to
stimulate the brain itself and then observe what happens
Methods include:
Chemical stimulation
Electrical stimulation
Magnetic stimulation
METHODS OF INVESTIGATING
BRAIN FUNCTION:
Accidental Damage
Deliberate Damage
Stimulation of the Brain
ACCIDENTAL DAMAGE
Researchers use these natural experiments to compare the
alteration in psychological functioning with the location
of damage by scan, surgery, or autopsy.
Damage may be caused by:
1. strokes
2. head trauma
3. virus
ADVANTAGES/DISADVANTAGES
Advantages: the altering damage occurs naturally so
there are less ethical problems compared to other
methods.
Disadvantages:
1. Lack of precision
2. Comparison problems
3. other non-physical effects may be
responsible for behavioral differences.
CASE STUDIES
Are useful when there are few examples of a particular
type of damage
Case studies can illustrate how we can determine brain
function by looking at what happens to behavior when
specific parts of the brain are damaged
Excellent example of a case study is Phineas Gage.
PHINEAS GAGE
Phineas P. Gage was a railroad
construction foreman now
remembered for his incredible
survival of an accident in which a
large iron rod was driven
completely through his head,
destroying one or both of his
brain's frontal lobes, and for that
injury's reported effects on his
personality and behavior—effects
said to be so profound that
friends saw him as "no longer
Gage."
PHINEAS GAGE
The damage to Gage’s
frontal cortex resulted in a
loss of social inhibitions,
which led to inappropriate
behavior.
Significant injury to the brain is often
fatal, but as noted earlier the iron's 1/4inch leading point may have reduced its
destructiveness, and apparently all
important blood vessels were spared.
Nonetheless, the brain tissue destroyed
must have been substantial (considering
not only the initial trauma but the
subsequent infection as well) though
debate as to whether this was in both
frontal lobes, or primarily the left,
began with the earliest papers by
physicians who had examined Gage
Gage is a fixture in the curricula of neurology,
psychology and related disciplines, and is frequently
mentioned in books and academic papers; he also has a
minor place in popular culture. Relative to this celebrity,
the body of known fact about the case is remarkably
small, so that historically it has been cited in support of
mutually incompatible theories of the brain
CLIVE WEARING
On March 27, 1985, Wearing, then an acknowledged
expert in early music at the height of his career with
BBC Radio 3, contracted a virus which normally causes
only cold sores.
In Wearing's case the virus attacked the brain (Herpes
simplex encephalitis). Since this point, he has been
unable to store new memories. He has also been unable
to control emotions and associate memories well.
CLIVE WEARING
Wearing developed a profound case of total amnesia as a
result of his illness. Because an area of the brain required
to transfer memories from working memory to long-term
memory is damaged, he is completely unable to form
lasting new memories. The damage was to his
hippocampus.
He spends every day 'waking up' every few seconds,
'restarting' his consciousness once the time span of his
short term memory elapses (about 30 seconds).
CLIVE WEARING
In a diary provided by his caretakers, Clive was encouraged to record his
thoughts. Page after page is filled with entries similar to the following:
8:31 AM: Now I am really, completely awake.
9:06 AM: Now I am perfectly, overwhelmingly awake.
9:34 AM: Now I am superlatively, actually awake
THE USE OF
TECHNOLOGY
Modern technology is now extensively used
because it provides an opportunity to study the
active brain.
It enables them to study localization of the
function of the brain. Many early experiments
used invasive techniques such as ablation and
lesioning.
STIMULATION OF
THE BRAIN
Electrical Stimulation- aims to stimulate brain areas
with microelectrodes to reveal their function through
behavioral change.
Examples:
-animal studies- Delgado
-human studies- Penfield
ELECTRICAL STIMULATION
Eduard Hitzig (1838-1907)
Hitzig in 1860’s worked on patients who
had pieces of their skulls blown away in
battle and he stimulated exposed brains
with wires connected to a battery
Gustav Fritish (1828-1929)
Fritish discovered weak electric shocks
applied to areas at the back of the brain,
caused the patients’ eyes to move.
ELECTRICAL STIMUALTION
Hitzig and Fritsch set up a makeshift lab in Fritsch’s house
Stimulated the brains of live dogs
Found that they could cause crude movements of the dog’s
bodies.
Found specific areas of the brain controlled specific movements
Question of ethics in non-human studies
WILDER PENFIELD
Wilder Penfield (1891-1976)
Neurosurgeon specializing in the surgical
treatment of epilepsy
Kept his patients awake so they could talk
to him about what they were feeling as he
stimulated areas of the brain to locate
seizure activity.
Developed a map of the somatosensory
cortex showing how much space is taken
up by the different regions of the body.
CHEMICAL STIMULATION
Microdialysis – a micropipette is used
to deliver a neurotransmitter into a
neuronal synapse
Can be used in reverse to extract
neurotransmitters
SCANS
EEG
Electroencephalogram
The EEG printout is often
referred to as “brainwaves”
When neurons transport
information they let off an
electrical charge. The EEG
registers the pattern of these
charges.
PET
Positron emission topography
Monitors glucose metabolism in the
brain.
Patients injected with radioactive
glucose and the scan picks up the
colored path of the glucose.
Used to diagnose tumors and
determine changes in Alzheimer’s
patients.
MAGNETIC STIMULATION
MRI- Magnetic Resonance Imaging
From this technique functional maps of
the brain can be generated
It provides three dimensional pictures of
brain structures using magnetic fields and
radio waves.
The MRI shows actual brain activity and
indicates which areas of the brain are
active when engaged in a behavior.
TRANS-CRANIAL MAGNETIC
STIMULATION
ADVANTAGES/DISADVANTAGES
Advantages
 Less Harmful to stimulate the brain then to
physically damage it.
 More Valid- it is a better way to investigate
living function of brain areas.
Disadvantages
 Invasive technique
 Interconnectedness
DELIBERATE DAMAGE
Ablation/Lesion Studies- these studies aim to investigate the
function by removing areas of the brain or destroying links
between areas.
Some of the psychological functions investigated have included:
-Motivation
-Aggression
-Memory
-Consciousness
-Psychopatholgy
Roger Sperry
EXPERIMENTAL EXPOSURE EFFECTS
These aim to influence
brain physiology by using
environmental distortion
or deprivation.
LESION
A lesion is when a part of
the brain is either
destroyed or its function is
disrupted.
Lesions can occur naturally
such as following a stroke
or after a seizure.
BRAIN LESIONS
Some lesions are from brain injury or trauma and some
experiments have been conducted to deliberately lesion a
portion of the brain.
BRAIN LESIONING
Some experiments have been conducted to
deliberately lesion the brain
Electrodes can be placed in the brain and a
current applied
Toxins can be injected into specific brain
sites using a micropipette
ABLATION
Ablation
is when a
part of the
brain is
removed.
MRI of
normal brain
(right) and
fluid-filled or
ablated brain
(left).
THE HM CASE
Henry Gustav Molaison (February 26, 1926 – December 2,
2008), better known as HM or H.M., was a memory-impaired
patient who was widely studied from the late 1950s until his death.
His case played a very important role in the development of
theories that explain the link between brain function and memory,
and in the development of cognitive neuropsychology, a branch
of psychology that aims to understand how the structure and
function of the brain relates to specific psychological processes.
HM’S BRAIN
HM suffered from
intractable epilepsy
that has been
often—though
inconclusively—
attributed to a
bicycle accident at
the age of nine
During the operation, his hippocampus was lesioned.
The
hippocampus
seems to act as a
"gateway"
through which
new fact
information must
pass before being
permanently
stored in memory
THE SURGERY
After the surgery—which was successful in its primary
goal of controlling his epilepsy—he suffered from
severe anterograde amnesia: although his working
memory and procedural memory were intact, he could
not commit new events to long-term memory
HM
He had to write notes to
himself all day long so that
he knew what he had eaten
for breakfast, that he had
already gotten his mail, and
so forth.
LEFT BRAIN/RIGHT BRAIN
Analytic
thought
Logic
Language
Science and
Math




Holistic
thought
Intuition
Creativity
Art and
music
LEFT HEMISPHERE
 Controls the right side of
the body
 Controls language &
speech, including reading
and writing
 Controls understanding
speech
 Controls speaking
 Controls verbal memory
(remembering things
heard)
RIGHT HEMISPHERE
 Recognizing shapes and
forms
 Musical and artistic
awareness
 Spatial organization and
perception
 Imagination
 Processing and storage of
visual data insight
 Generating mental images
of sight, sound, touch, taste
and smell
SPLIT BRAIN- ROGER SPERRY
In the 19th century, research on
people with certain brain injuries,
made it possible to suspect that the
"language center" in the brain was
commonly situated in the left
hemisphere.
One had observed that people with
lesions in two specific areas on the
left hemisphere lost their ability to
talk, for example.
RIGHT BRAIN/LEFT BRAIN
In the 1960s, there was no other cure for
people who suffered from a special kind
of epilepsy than by cutting off the
connection, corpus callosum, between the
two hemispheres.
Sperry had 10 patients who underwent
the operation.
The area used to transfer information
from the right hemisphere to the left
hemisphere was disrupted.
For right-handed people and most lefthanded people, language is organized in the
left brain.
The right hemisphere has very little
understanding of language.
The right brain organizes non-visual
imagery.
When patients with a split brain are
shown an image in their left visual field
(the left half of what both eyes take in
, they cannot vocally name what they
have seen.
This is because the speech-control
center is in the left side of the brain in
most people, and the image from the
left visual field is sent only to the right
side of the brain (those with the speech
control center in the right side
experience similar symptoms when an
image is presented in the right visual
field).
The same effect occurs for visual pairs and reasoning. For
example, a patient with split brain is shown a picture of a
chicken and a snowy field in separate visual fields and asked to
choose from a list of words the best association with the
pictures.
The patient would choose a chicken foot to associate with the
chicken and a shovel to associate with the snow; however,
when asked to reason why the patient chose the shovel, the
response would relate to the chicken (e.g. "the shovel is for
cleaning out the chicken coop").
Right vision field is
connected to the left
hemisphere.
Left vision field is
connected to the right
hemisphere.
“SPLIT BRAIN” STUDIES
Robert Sperry
Visual field information is processed in the contralateral hemisphere
ADVANTAGES/DISADVANTAGES
Advantages:
Greater control and
precision in the location of
the damage.
Ability to compare the
behavior before and after
the alteration.
Disadvantages:
Ethical problems of
intervention.
Non-human findings
Plasticity- the brain can
compensate for damage.
Might not disturb the
performance of the rest of
the brain.
METHODS OF INVESTIGATING BRAIN FUNCTION
MEASUREMENT
Direct Recording of Neuronal Activity
Microelectrodes are inserted into single neural cells and
record their electrochemical activity.
Hubel and Wiesel measured the activity of single
neuronal cells in the visual cortex of monkeys.
ADVANTAGES/DISADVANTAGES
Advantages: Extremely precise.
Disadvantages:
-very time-consuming.
-too focused, neglects the interactions between nerve
cells.
-invasive method
PLASTICITY
Before the 1960’s, the brain was thought only to be influenced
by genetics and therefor considered unchangeable.
This distinctive trait makes the brain a very valuable organ, as
it can constantly adapt itself to deal with new input and
information. All animals possess this characteristic to some
extent, although most studies have focused specifically on the
workings of the human brain.
Hubel and Wiesel: demonstrated that the brain could
change as a response to environmental input.
BRAIN PLASTICITY
 Plasticity can change the functional
qualities of various brain structures
depending on the regularity and type of
new tasks the neurons are asked to
perform.
 High levels of stimulation and numerous
learning opportunities at appropriate times
lead to a greater density of neural
connections.
DENDRITE BRANCHING
Dendrite Branching: Every time we learn something
new the neurons connect to create a new.
ROSENZWEIG AND BENNETT
Researchers to carried out a series of studies
where they placed rats into one of two
environments to measure the effect of either
enrichment or deprivation on the development
of neurons in the cerebral cortex.
THE MOZART EFFECT
 One of the most well known claims of brain
plasticity is the Mozart Effect.
 The reported phenomenon is listening to Mozart will
temporarily increase spatial reasoning ability. It
suggests that exposure to music compositions that
are structurally complex excites the same brain-firing
pattern as when completing spatial tasks.
MOZART EFFECT
While some supportive reports have
been published, studies with positive
results have tended to be associated with
any form of music that has energetic and
positive emotional qualities.
Among children, some studies suggest
no effect on IQ or spatial ability.
The weight of subsequent evidence
supports either a null effect, or shortterm effects related to increases in mood
and arousal.
MIRROR NEURON
How Brain's 'Mirrors' Aid Our Social Understanding ,
he writes that one of the most intriguing theories to
emerge in recent years about how our brains perform is
that we have neurons that essentially act as mirrors to
other people.
When we see someone scratch their head or furrow
their brow, we instantly have a sense of their mental
state because those actions trigger the same patterns of
neural activity in our own minds and allow our brains to
quickly deduce what mental states are associated with
such patterns.
MIRROR NEURON
• One way in which the brain interacts with the
environment has to do with how people
learn.
• Recent research shows that special neurons,
called mirror neurons, may play a vital role in
the ability to learn.
• It may also allow a person to empathize with
another person.
• The mirror neuron fires when a person
performs an action or observes someone else
perform the same action.
GALLESE 1996
 In 1996, Gallese was able to isolate the neural response in
monkeys reaching for food.
 Every time the monkey would reach for food the neurons
were release an electrical charge. A crackling sound
would be emitted when this happens.
 One day the researcher reached for the peanut and heard
the crackling of the electrical charge. The monkey’s brain
fired the neuron while watching someone else exhibit the
behavior.
HANDEDNESS
Studying from pre-historic times, right-handedness prevails
in all human cultures. Bias toward the right hand is unique
to humans and primates.
Right-handedness is most common. Right-handed people are
more dexterous with their right hands when performing a
task.
Left-handedness is less common than right-handedness. Lefthanded people are more dexterous with their left hands
when performing a task. About 8-15% of people are lefthanded.
MIXED
HANDED/ABIDEXTERITY
Mixed-handedness, also known as cross-dominance, is being
able to do different tasks better with different hands. For
example, mixed-handed persons might write better with
their right hand but throw a ball more efficiently with their
left hand.
Ambidexterity is exceptionally rare, although it can be
learned. A true ambidextrous person is able to do any task
equally well with either hand. Those who learn it still tend
to sway towards their originally dominant hand.
LEFT HAND DISCRIMINATION
This unfair treatment of lefties was--and still is--a worldwide
phenomenon.
In many parts of the world, the left hand is considered
"unclean," and left-handedness is simply not tolerated; the
word for "left" often has strongly negative connotations
LEFTIES ARE THE ONLY ONES IN THE RIGHT MIND.
90% of the population is righthanded. Of the 10% who are lefthanded, there are more males than
females.
95% of right-handers process
information in their left hemisphere,
which tends to be slightly larger.
Left-handers tend to be more diverse.
50% process speech in their left
hemisphere, as right-handers do.
25% process language in the right
hemisphere, the other quarter use
both hemispheres.
LEFTY BRAIN TEASERS
Because their brains are organized differently, left-handers see and
think differently and can get some very different results from various
"brain tests", usually doing very well on tests that involve creative
thinking or unraveling complex images and manipulating 3D images.
Here's a famous test of creativity - have a look at the image below:
THURSTON'S HAND TEST
The left-handed brain's mastery of the visual has an important benefit - it can "see"
three dimensionally. In Thurston's hand test, you are asked to identify which
pictures are of left hands and which are of right hands. Your right-handed brain is
at a loss to handle this problem, but your left-handed brain can actually rotate these
drawings in imaginary space to solve the test - have a go!
FAMOUS LEFT-HANDERS
Luke Skywalker
Julius Caesar
Beethoven
Sarah Jessica Parker
Leonardo da Vinci
Tom Cruise
Aristotle
Gandhi
Matthew Broderick
Alexander the Great
Imagine the centre of your back is itching. Which hand do you scratch it with?
Interlock your fingers. Which thumb is uppermost?
Imagine you are applauding. Start clapping your hands. Which hand is uppermost?
Wink at and imaginary friend straight in front of you. Which eye does the winking?
Put your hands behind your back, one holding the other. Which hand is doing the
holding?
Someone in front of you is shouting but you cannot hear the words. Cup your ear to
hear better. Which ear do you cup?
Count to three on your fingers, using the forefinger of the other hand. Which
forefinger do you use?
Tilt your head to one shoulder. Which shoulder does it touch?
Fixate a small distant object with your eyes and point directly at it with your forefinger.
Now close one eye. Now change eyes. Which eye was open when the fingertip
remained in line with the small object? (when the other eye, the non-dominant
one, is open and the dominant eye is closed, the finger will appear to move to
one side of the object.)
Fold your arms. Which forearm is uppermost?