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THE BIOLOGICALTHE BIOLOGICALPERSPECTIVEPERSPECTIVE
Biological PerspectiveBiological Perspective
Linking the Linking the introspective study of introspective study of consciousnessconsciousness (what you are thinking and (what you are thinking and feeling based on mental self-report)feeling based on mental self-report)
With what is happening at the biological With what is happening at the biological level?level? ( (brain activitybrain activity at different sites and at different sites and changes in chemical messengers)changes in chemical messengers)
MethodologiesMethodologies
Correlational Studies Correlational Studies
ExperimentsExperiments
ObservationsObservations
Case StudiesCase Studies
Brain/Behavior LinkBrain/Behavior Link
Our ancestors understood that the brain Our ancestors understood that the brain and behavior are linkedand behavior are linked..
For example a For example a strong blow to the headstrong blow to the head 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 parts show evidence that parts of the skull were of the skull were deliberately removeddeliberately removed..
May have been a medical May have been a medical treatment or to release treatment or to release evil spirits.evil spirits.
Sometimes practices by Sometimes practices by tribal groups in tribal groups in “religious” “religious” ceremonies.ceremonies.
The presence of The presence of trepanated skulls does trepanated skulls does suggest an awareness of suggest an awareness of the link between brain the link between brain and behaviorand behavior..
Correlational StudiesCorrelational Studies Psychologists Psychologists investigate the relationship investigate the relationship
between the brain and behaviorbetween the brain and behavior by by examining what happens after the examining what happens after the brain is brain is damaged – either accidentally or damaged – either accidentally or deliberately as part of an experimentdeliberately as part of an experiment
Examples include: Examples include: stroke, epileptic seizure stroke, epileptic seizure or head injuryor 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 itselfstimulate the brain itself 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 experiments Researchers use these natural experiments
to compare the alteration in psychological to compare the alteration in psychological functioning with the location of damage by functioning with the location of damage by scan, surgery, or autopsy.scan, 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 problems naturally so there are less ethical problems compared to other methods.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 large an accident in which a large iron rod was driven 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 Gage’s The damage to Gage’s frontal cortex resulted frontal cortex resulted in a loss of social in a loss of social inhibitions, which led inhibitions, which led to inappropriate to inappropriate behavior.behavior.
Significant injury to the brain is often Significant injury to the brain is often fatalfatal, but as noted earlier the iron's , but as noted earlier the iron's 1/4-inch leading point may have 1/4-inch leading point may have reduced its destructiveness, and reduced its destructiveness, and apparently all important blood vessels apparently all important blood vessels were spared. were spared.
Nonetheless, the Nonetheless, the brain tissue brain tissue destroyed must have been substantialdestroyed must have been substantial (considering not only the initial (considering not only the initial trauma but the subsequent infection trauma but the subsequent infection as well) as well) though debate as to whether though debate as to whether this was in both frontal lobes, or this was in both frontal lobes, or primarily the left,primarily the left, began with the began with the earliest papers by physicians who had earliest papers by physicians who had examined Gage examined Gage
Gage is a fixture in the curricula of neurology, Gage is a fixture in the curricula of neurology, psychology and related disciplines, and is psychology and related disciplines, and is frequently mentioned in books and academic frequently mentioned in books and academic papers; he also has a minor place in popular papers; he also has a minor place in popular culture. Relative to this celebrity, the body of culture. Relative to this celebrity, the body of known fact about the case is remarkably small, known fact about the case is remarkably small, so that historically it has been cited in support so that historically it has been cited in support of mutually incompatible theories of the brain of mutually incompatible theories of the brain
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 only contracted a virus which normally causes only cold sores.cold sores.
In Wearing's case the virus attacked the brain In Wearing's case the virus attacked the brain (Herpes simplex encephalitis). Since this point, (Herpes simplex encephalitis). Since this point, he has been unable to store new memories. He he has been unable to store new memories. He has also been unable to control emotions and has also been unable to control emotions and associate memories well. associate memories well.
Clive WearingClive Wearing
Wearing developed a profound case of total amnesia as a result of his Wearing developed a profound case of total amnesia as a result of his illness. Because illness. Because an area of the brain required to transfer memories an area of the brain required to transfer memories from working memory to long-term memory is damaged, he is from working memory to long-term memory is damaged, he is completely unable to form lasting new memoriescompletely unable to form lasting new memories. .
He spends every day 'waking up' every few seconds, 'restarting' his He spends every day 'waking up' every few seconds, 'restarting' his consciousness once the time span of his short term memory elapses consciousness once the time span of his short term memory elapses (about 30 seconds). (about 30 seconds).
He remembers little of his life before 1985; he knows, for example, He remembers little of his life before 1985; he knows, for example, that he has children from an earlier marriage, but cannot remember that he has children from an earlier marriage, but cannot remember their names. their names.
Clive WearingClive Wearing
In a diary provided by his caretakers, Clive In a diary provided by his caretakers, Clive was encouraged to record his thoughts. was encouraged to record his thoughts. Page after page is filled with entries Page after page is filled with entries similar to the following: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 awake.9:06 AM: Now I am perfectly, overwhelmingly awake.
9:34 AM: Now I am superlatively, actually awake9:34 AM: Now I am superlatively, actually awake
Test FridayTest Friday Know the difference between biological, Know the difference between biological,
cognitive, and learning perspectives.cognitive, and learning perspectives. Ethical ConsiderationsEthical Considerations ReductionismReductionism Freewill/DeterminismFreewill/Determinism Structuralism/FunctionalismStructuralism/Functionalism Collectivism/IndividualismCollectivism/Individualism Cultural BiasCultural Bias
Stimulation of the BrainStimulation of the Brain Electrical Stimulation- Electrical Stimulation- aims to stimulate aims to stimulate
brain areas with microelectrodes to reveal their brain areas with microelectrodes to reveal their function through behavioral change.function through behavioral 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 who Hitzig in 1860’s worked on patients who
had had pieces of their skulls blown away in pieces of their skulls blown away in battle and he stimulated exposed brains battle and he stimulated exposed brains with wires connected to a batterywith wires connected to 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 brain,applied to areas at the back of the brain, caused the patients’ eyes to move.caused the patients’ eyes to move.
Electrical StimualtionElectrical Stimualtion
Hitzig and Fritsch set up a makeshift lab in Hitzig and Fritsch set up a makeshift lab in Fritsch’s houseFritsch’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 the Neurosurgeon specializing in the
surgical treatment of epilepsysurgical treatment of epilepsy Kept his patients awakeKept his patients awake so they so they
could talk to him about what they could talk to him about what they were feeling as were feeling as he stimulated areas he stimulated areas of the brain to locate seizure of the brain to locate seizure activity.activity.
Developed a map of the Developed a map of the somatosensory cortex showing how somatosensory cortex showing how much space is taken up by the much space is taken up by the different regions of the body.different regions of the body.
Chemical StimulationChemical Stimulation
Microdialysis – a micropipette is Microdialysis – a micropipette is used to deliver a used to deliver a neurotransmitter into a neurotransmitter into a neuronal synapseneuronal synapse
Can be used in reverse to Can be used in reverse to extract neurotransmittersextract neurotransmitters
Magnetic StimulationMagnetic Stimulation Transcranial Magnetic StimulationTranscranial Magnetic Stimulation 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 be active, that is, the neurons can be “switched on and off” “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 StimulationTrans-cranial Magnetic Stimulation
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 brain investigate the function by removing areas of the brain or destroying links between areas.or destroying links between areas.
Some of the psychological functions investigated have Some of the psychological functions investigated have included:included:
-Motivation-Motivation-Aggression-Aggression-Memory-Memory-Consciousness-Consciousness
-Psychopatholgy-Psychopatholgy
Roger Sperry
Experimental Exposure EffectsExperimental Exposure Effects
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 its destroyed or its function is disruptedfunction is disrupted..
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 and Some lesions are from brain injury or trauma and some experiments have been conducted to some experiments have been conducted to deliberately lesion a portion of the brain.deliberately lesion a portion of the brain.
Brain LesioningBrain Lesioning
Some experiments have been conducted Some experiments have been conducted to deliberately lesion the brainto deliberately lesion the brain
Electrodes can be placed in the brain and Electrodes can be placed in the brain and a current applieda current applied
Toxins can be injected into specific brain Toxins can be injected into specific brain sites using a micropipettesites using a micropipette
AblationAblationAblationAblation
is when a is when a part of part of
the brain the brain is is
removed.removed.MRI of MRI of normal normal brain brain (right) (right)
and fluid-and 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 was a memory-impaired patient who was widely studied from memory-impaired patient who was widely studied from the late 1950s until his death.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 between theories that explain the link between brain function and memory,brain function and memory, and in the development of and in the development of cognitive neuropsychology, a branch of psychology that cognitive neuropsychology, a branch of psychology that aims to understand how the structure and function of aims to understand how the structure and function of the brain relates to specific psychological processes. the brain relates to specific psychological processes.
HM’s BrainHM’s Brain
HM suffered HM suffered from intractable from intractable epilepsy epilepsy that has that has been often—been often—though though inconclusively—inconclusively—attributed to a attributed to a bicycle accident bicycle accident at the age of at the age of nine nine
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 severe anterograde —he suffered from severe anterograde amnesia: although his working memory amnesia: although his working memory and procedural memory were intact, he and procedural memory were intact, he could not commit new events to long-term could not commit new events to long-term memory memory
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.
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 the Ability to compare the behavior before and behavior before and after the alteration.after 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.
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 short-required to transfer memories from short-term to long-term memory is damaged, he term to long-term memory is damaged, he is completely unable to form lasting new is completely unable to form lasting new memories – his memory only lasts memories – his memory only lasts between 7 and 30 seconds between 7 and 30 seconds
Methods of Investigating Brain FunctionMeasurement
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
External Recording of Brain Activity
Aims to detect brain activity from measurements made at the surface of the skull.
EEG-electroencephalograms-brain waves under the scalp.
EOG- electrooculargrams- eye movement EMG- electrobyograms- muscles to measure
tension
Advantages/Disadvantages
Advantages Non-invasive Practical for use
with sleep, brain damage, epilepsy, and Alzheimer’s disease, etc..
Disadvantages Crude measure. The EEG’s
indicate the activity level but not the precise function of the neurons involved.
