THE BIOLOGICALTHE BIOLOGICALPERSPECTIVEPERSPECTIVE

Biological PerspectiveBiological Perspective

Linking the Linking the introspective study of introspective study of consciousnessconsciousness (what you are thinking (what you are thinking and feeling based on mental self-and feeling based on mental self-report)report)

With what is happening at the biological With what is happening at the biological level?level? ( (brain activitybrain activity at different sites at different sites and changes in chemical messengers)and changes in chemical messengers)

MethodologiesMethodologies

Correlational Studies Correlational Studies

ExperimentsExperiments

ObservationsObservations

Case StudiesCase Studies

Brain/Behavior LinkBrain/Behavior Link

Our ancestors understood that the Our ancestors understood that the brain and behavior are linkedbrain and behavior are linked..

For example a For example a strong blow to the strong blow to the headhead can result in: can result in: A change of consciousnessA change of consciousness A change in perceptionA change in perception Memory lossMemory loss Loss of movementLoss of movement

TrepanationTrepanation 40,000 –year-old skulls 40,000 –year-old skulls

show evidence that show evidence that parts of the skull were parts of the skull were deliberately removeddeliberately removed..

May have been a May have been a medical treatment or medical treatment or to release evil spirits.to release evil spirits.

Sometimes practices Sometimes practices by tribal groups in by tribal groups in “religious” ceremonies.“religious” ceremonies.

The presence of The presence of trepanated skulls does trepanated skulls does suggest an awareness suggest an awareness of the link between of the link between brain and behaviorbrain and behavior..

Correlational StudiesCorrelational Studies Psychologists Psychologists investigate the investigate the

relationship between the brain and relationship between the brain and behaviorbehavior by examining what happens by examining what happens after the after the brain is damaged – either brain is damaged – either accidentally or deliberately as part of an accidentally or deliberately as part of an experimentexperiment

Examples include: Examples include: stroke, epileptic stroke, epileptic seizure or head injuryseizure or head injury

Studies are Studies are correlationalcorrelational because because changes in behavior are assumed to be changes in behavior are assumed to be related to brain damagerelated to brain damage

ObservationsObservations

An alternative way of studying brain An alternative way of studying brain function is to function is to stimulate the brain stimulate the brain itselfitself and and then observe what happensthen observe what happens

Methods include:Methods include: Chemical stimulationChemical stimulation Electrical stimulationElectrical stimulation Magnetic stimulationMagnetic stimulation

Methods of Investigating Brain Methods of Investigating Brain Function:Function:

Accidental DamageAccidental Damage

Deliberate DamageDeliberate Damage

Stimulation of the BrainStimulation of the Brain

ACCIDENTAL DAMAGEACCIDENTAL DAMAGE Researchers use these natural Researchers use these natural

experiments to compare the experiments to compare the alteration in psychological functioning alteration in psychological functioning with the location of damage by scan, with the location of damage by scan, surgery, or autopsy.surgery, or autopsy.

Damage may be caused by:Damage may be caused by:1. strokes1. strokes

2. head trauma2. head trauma 3. virus3. virus

Advantages/DisadvantagesAdvantages/Disadvantages

Advantages:Advantages: the altering damage occurs the altering damage occurs naturally so there are less ethical naturally so there are less ethical problems compared to other methods.problems compared to other methods.

Disadvantages:Disadvantages:

1. Lack of precision1. Lack of precision

2. Comparison problems2. Comparison problems

3. other non-physical effects may be 3. other non-physical effects may be

responsible for behavioral differences.responsible for behavioral differences.

Case StudiesCase Studies Are useful when there are Are useful when there are few examples few examples

of a particular type of damageof a particular type of damage

Case studies can illustrate how we can Case studies can illustrate how we can determine brain function by looking at determine brain function by looking at what happens to behavior when specific what happens to behavior when specific parts of the brain are damagedparts of the brain are damaged

Excellent example of a case study is Excellent example of a case study is Phineas Gage.Phineas Gage.

Phineas GagePhineas Gage Phineas P. GagePhineas P. Gage was a was a railroad construction railroad construction foreman now remembered foreman now remembered for his incredible survival of for his incredible survival of an accident in which a an accident in which a large iron rod was driven large iron rod was driven completely through his completely through his head, destroying one or head, destroying one or both of his brain's frontal both of his brain's frontal lobes, and for that injury's lobes, and for that injury's reported effects on his reported effects on his personality and behavior—personality and behavior—effects said to be so effects said to be so profound that friends saw profound that friends saw him as "no longer Gage."him as "no longer Gage."

Phineas GagePhineas Gage

The damage to The damage to Gage’s frontal Gage’s frontal cortex resulted in a cortex resulted in a loss of social loss of social inhibitions, which inhibitions, which led to inappropriate led to inappropriate behavior.behavior.

Significant injury to the brain is Significant injury to the brain is often fataloften fatal, but as noted earlier , but as noted earlier the iron's 1/4-inch leading point the iron's 1/4-inch leading point may have reduced its may have reduced its destructiveness, and apparently destructiveness, and apparently all important blood vessels were all important blood vessels were spared. spared.

Nonetheless, the Nonetheless, the brain tissue brain tissue destroyed must have been destroyed must have been substantialsubstantial (considering not only (considering not only the initial trauma but the the initial trauma but the subsequent infection as well) subsequent infection as well) though debate as to whether this though debate as to whether this was in both frontal lobes, or was in both frontal lobes, or primarily the left,primarily the left, began with the began with the earliest papers by physicians who earliest papers by physicians who had examined Gage had examined Gage

Gage is a fixture in the curricula of Gage is a fixture in the curricula of neurology, psychology and related neurology, psychology and related disciplines, and is frequently mentioned in disciplines, and is frequently mentioned in books and academic papers; he also has a books and academic papers; he also has a minor place in popular culture. Relative to minor place in popular culture. Relative to this celebrity, the body of known fact about this celebrity, the body of known fact about the case is remarkably small, so that the case is remarkably small, so that historically it has been cited in support of historically it has been cited in support of mutually incompatible theories of the brain mutually incompatible theories of the brain

http://rds.yahoo.com/_ylt=A0PDoYBEPY9M0E8AtTejzbkF/SIG=12dhg3khd/EXP=1284542148/**http%3A//joeltalks.com/web_images/phineas_gage_mcmillan.jpg

CLIVE WEARINGCLIVE WEARING

On March 27, 1985, Wearing, then an On March 27, 1985, Wearing, then an acknowledged expert in early music at the acknowledged expert in early music at the height of his career with BBC Radio 3, height of his career with BBC Radio 3, contracted a virus which normally causes contracted a virus which normally causes only cold sores.only cold sores.

In Wearing's case the virus attacked the In Wearing's case the virus attacked the brain (Herpes simplex encephalitis). Since brain (Herpes simplex encephalitis). Since this point, he has been unable to store this point, he has been unable to store new memories. He has also been unable to new memories. He has also been unable to control emotions and associate memories control emotions and associate memories well. well.

Clive WearingClive Wearing Wearing developed a profound case of total amnesia as a Wearing developed a profound case of total amnesia as a

result of his illness. Because result of his illness. Because an area of the brain required to an area of the brain required to transfer memories from working memory to long-term transfer memories from working memory to long-term memory is damaged, he is completely unable to form lasting memory is damaged, he is completely unable to form lasting new memoriesnew memories. .

He spends every day 'waking up' every few seconds, He spends every day 'waking up' every few seconds, 'restarting' his consciousness once the time span of his short 'restarting' his consciousness once the time span of his short term memory elapses (about 30 seconds). term memory elapses (about 30 seconds).

He remembers little of his life before 1985; he knows, for He remembers little of his life before 1985; he knows, for example, that he has children from an earlier marriage, but example, that he has children from an earlier marriage, but cannot remember their names. cannot remember their names.

Clive WearingClive Wearing

In a diary provided by his caretakers, In a diary provided by his caretakers, Clive was encouraged to record his Clive was encouraged to record his thoughts. Page after page is filled with thoughts. Page after page is filled with entries similar to the following:entries similar to the following:

8:31 AM: Now I am really, completely awake.8:31 AM: Now I am really, completely awake.9:06 AM: Now I am perfectly, overwhelmingly 9:06 AM: Now I am perfectly, overwhelmingly awake.awake.

9:34 AM: Now I am superlatively, actually awake9:34 AM: Now I am superlatively, actually awake

Wearing developed a profound case of Wearing developed a profound case of total amnesia as a result of his illness. total amnesia as a result of his illness. Because the hippocampus, an area Because the hippocampus, an area required to transfer memories from required to transfer memories from short-term to long-term memory is short-term to long-term memory is damaged, he is completely unable to damaged, he is completely unable to form lasting new memories – his form lasting new memories – his memory only lasts between 7 and 30 memory only lasts between 7 and 30 seconds seconds

Stimulation of the BrainStimulation of the Brain Electrical Stimulation- Electrical Stimulation- aims to aims to

stimulate brain areas with microelectrodes stimulate brain areas with microelectrodes to reveal their function through behavioral to reveal their function through behavioral change.change.

Examples:Examples:

-animal studies- Delgado-animal studies- Delgado

-human studies- Penfield-human studies- Penfield

Electrical StimulationElectrical StimulationEduard Hitzig (1838-1907)Eduard Hitzig (1838-1907) Hitzig in 1860’s worked on patients Hitzig in 1860’s worked on patients

who had who had pieces of their skulls blown pieces of their skulls blown away in battle and he stimulated away in battle and he stimulated exposed brains with wires connected exposed brains with wires connected to a batteryto a battery

Gustav Fritish (1828-1929)Gustav Fritish (1828-1929) Hitzig discovered Hitzig discovered weak electric shocks weak electric shocks

applied to areas at the back of the applied to areas at the back of the brain,brain, caused the patients’ eyes to caused the patients’ eyes to move.move.

Electrical StimualtionElectrical Stimualtion

Hitzig and Fritsch set up a makeshift lab Hitzig and Fritsch set up a makeshift lab in Fritsch’s housein Fritsch’s house

Stimulated the brains of live dogsStimulated the brains of live dogs Found that they could cause Found that they could cause crude crude

movements of the dog’s bodies.movements of the dog’s bodies. Found specific areas of the brain Found specific areas of the brain

controlled specific movementscontrolled specific movements Question of ethics in non-human studiesQuestion of ethics in non-human studies

Wilder PenfieldWilder Penfield Wilder PenfieldWilder Penfield (1891-1976) (1891-1976) Neurosurgeon specializing in Neurosurgeon specializing in

the the surgical treatment of surgical treatment of epilepsyepilepsy

Kept his patients awakeKept his patients awake so so they could talk to him about they could talk to him about what they were feeling as what they were feeling as he he stimulated areas of the brain to stimulated areas of the brain to locate seizure activity.locate seizure activity.

Developed a map of the Developed a map of the somatosensory cortex showing somatosensory cortex showing how much space is taken up by how much space is taken up by the different regions of the the different regions of the body.body.

Chemical StimulationChemical Stimulation

Microdialysis – a Microdialysis – a micropipette is used to micropipette is used to deliver a neurotransmitter deliver a neurotransmitter into a neuronal synapseinto a neuronal synapse

Can be used in reverse to Can be used in reverse to extract neurotransmittersextract neurotransmitters

Magnetic StimulationMagnetic Stimulation Transcranial Magnetic Transcranial Magnetic

StimulationStimulation A magnetic coil is held on the A magnetic coil is held on the

scalp and depending on the scalp and depending on the strength of the current, the brain strength of the current, the brain areas can be made more or less areas can be made more or less active, that is, the neurons can active, that is, the neurons can be “switched on and off”be “switched on and off”

From this technique functional From this technique functional maps of the brain can be maps of the brain can be generatedgenerated

Trans-cranial Magnetic Trans-cranial Magnetic StimulationStimulation

Advantages/DisadvantagesAdvantages/Disadvantages

AdvantagesAdvantages Less Harmful to stimulate the brain then Less Harmful to stimulate the brain then

to physically damage it.to physically damage it. More Valid- it is a better way to More Valid- it is a better way to

investigate living function of brain areas.investigate living function of brain areas.

DisadvantagesDisadvantages Invasive techniqueInvasive technique InterconnectednessInterconnectedness

Deliberate DamageDeliberate Damage Ablation/Lesion Studies- Ablation/Lesion Studies- these studies aim to these studies aim to

investigate the function by removing areas of the investigate the function by removing areas of the brain or destroying links between areas.brain or destroying links between areas.

Some of the psychological functions investigated Some of the psychological functions investigated have included:have included:

-Motivation-Motivation

-Aggression-Aggression

-Memory-Memory

-Consciousness-Consciousness

-Psychopatholgy-Psychopatholgy

Roger Sperry

Experimental Exposure Experimental Exposure EffectsEffects

These aim to These aim to influence brain influence brain physiology by physiology by using using environmental environmental distortion or distortion or deprivation.deprivation.

LesionLesion

A lesion is when a A lesion is when a part of the brain is part of the brain is either either destroyed or destroyed or its function is its function is disrupteddisrupted..

Lesions can occur Lesions can occur naturally such as naturally such as following a stroke or following a stroke or after a seizure.after a seizure.

BRAIN LESIONSBRAIN LESIONS

Some lesions are from brain injury or trauma Some lesions are from brain injury or trauma and some experiments have been conducted and some experiments have been conducted to deliberately lesion a portion of the brain.to deliberately lesion a portion of the brain.

Brain LesioningBrain Lesioning

Some experiments have been Some experiments have been conducted to deliberately lesion the conducted to deliberately lesion the brainbrain

Electrodes can be placed in the brain Electrodes can be placed in the brain and a current appliedand a current applied

Toxins can be injected into specific Toxins can be injected into specific brain sites using a micropipettebrain sites using a micropipette

AblationAblationAblationAblation

is when a is when a part of part of

the brain the brain is is

removedremoved..

MRI of MRI of normal normal brain brain (right) (right) and and

fluid-fluid-filled or filled or ablated ablated brain brain (left).(left).

The HM CaseThe HM Case

Henry Gustav MolaisonHenry Gustav Molaison (February 26, 1926 – (February 26, 1926 – December 2, 2008), better known as December 2, 2008), better known as HMHM or or H.M.H.M., , was a memory-impaired patient who was widely was a memory-impaired patient who was widely studied from the late 1950s until his death.studied from the late 1950s until his death.

His case played a very important role in the His case played a very important role in the development of development of theories that explain the link theories that explain the link between brain function and memory,between brain function and memory, and in the and in the development of cognitive neuropsychology, a development of cognitive neuropsychology, a branch of psychology that aims to understand branch of psychology that aims to understand how the structure and function of the brain how the structure and function of the brain relates to specific psychological processes. relates to specific psychological processes.

HM’s BrainHM’s Brain

HM suffered HM suffered from from intractable intractable epilepsy epilepsy that that has been oftenhas been often—though —though inconclusivelyinconclusively—attributed to —attributed to a bicycle a bicycle accident at the accident at the age of nine 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 SurgeryThe Surgery

After the surgery—which was After the surgery—which was successful in successful in its primary goal of controlling his its primary goal of controlling his epilepsyepilepsy—he suffered from —he suffered from severe anterograde severe anterograde amnesia: although his working memory amnesia: although his working memory and procedural memory were intacand procedural memory were intact, he t, he could not commit new events to long-term could not commit new events to long-term memory 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 HemisphereLeft Hemisphere Controls the right side Controls the right side

of the bodyof the body Controls language & Controls language &

speech, including speech, including reading and writingreading and writing

Controls Controls understanding speechunderstanding speech

Controls speakingControls speaking Controls verbal Controls verbal

memory memory (remembering things (remembering things heard)heard)

Right HemisphereRight Hemisphere Recognizing shapes Recognizing shapes

and formsand forms Musical and artistic Musical and artistic

awarenessawareness Spatial organization Spatial organization

and perceptionand perception ImaginationImagination Processing and storage Processing and storage

of visual data insightof visual data insight Generating mental Generating mental

images of sight, sound, images of sight, sound, touch, taste and smelltouch, 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 left-handed people, language is organized in the left brain.

The right hemisphere has very little understanding of language.

The right brain organizes non-visual imagery.

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/DisadvantagesAdvantages/Disadvantages

Advantages:Advantages: Greater control and Greater control and

precision in the precision in the location of the location of the damage.damage.

Ability to compare Ability to compare the behavior the behavior before and after before and after the alteration.the alteration.

Disadvantages:Disadvantages: Ethical problems of Ethical problems of

intervention.intervention. Non-human findingsNon-human findings Plasticity- the brain Plasticity- the brain

can compensate for can compensate for damage. Might not damage. Might not disturb the disturb the performance of the performance of the rest of the brain.rest of the brain.

Methods of Investigating Brain Function

MeasurementDirect 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

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. Left-handed people are more dexterous with their left hands when performing a task. About 8-15% of people are left-handed.

Mixed Handed/Ambidexterity

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 right-handed. Of the 10% who are left-handed, 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?