biopsychology

Localisation

P brain scan evidence to support

Eg Peterson - wernickes area was active during a listening task and Broca’s area was active during a reading task supporting the key assumptions about both of these areas

P cast study evidence

Eg phineas gage

P support from modern neurosurgery

Eg. Cingulotomy for OCD

P - certain functions appear to not be localised

Eg learning

P - research supports that localised functions are not set

Eg plasticity

Lateralisation

Evidence - sperry studied patients who and corpus callosotomy and compared to controls

He compared their performance on a series of visual and tactile tasks to test the functions of the independent L/R hemispheres

Findings - drawing better when seen in left visual field so drawn by left hand (controlled by right hemisphere). If shown a composite picture they would name what is in the right visual field only, but can select a matching image to what was shown in left visual field. If visual field presented with different words or pictures they could only name the one shown in right visual field but could select a matching object with the left hand if shown to the left visual field.

Conclusions - language in left, drawing in right

Ao3

+quasi experiment in controlled conditions

-lacks ecological validity as in real life the patients can just shift view so it is processed by each eye

-low population validity - sample was 11 pps

fMRI

Scanner used magnets ti pick up the iron in the Haemoglobin in the blood. More iron is shown up as brighter areas on the scan, more active areas of the brain need more oxygen so they have an increase in blood flow.

+risk free and non invasive

+high quality images that shows function and structure of the brain

-only measures blood flow not neuron activity

-has poor temporal resolution - 5 sec time lag

EEG

Used to monitor electrical (therefore neuronal) activity in the brain. The pps wear a cap with many electrodes on it all over the head, electrodes detect small electrical charges resulting from the activity of millions of neurons.

+been invaluable in diagnosing conditions like epilepsy and understanding sleep

+high temporal resolution

-produces very generalised information of brain activity

-it does not provide a clear image of the brain, just locates the electrodes

Post Morton

Examining structural damage to the brain after death to establish how/what damage leads to specific deficits

What is is used for? Done on patients who typically have rare deficits in mental processes or behaviour eg HM

+vital before neuroimaging became possible

+allows exploration of feel per areas within the brain

-difficult to establish causation of functions

-there are so many factors that can affect the quality and variety of data

ERP

measures the eldtircial activity in the Brian thta results from specific stimuli (events), all inconsistent Briana ctivity is filtered out to leave only thr ERP, over rear tires or presenting a stimulus - if the brain activity is recorded consistently to this stimulus it can be argued to be the brains processing of that stimulus

+measure active that related to specific tasks

Plasticity

Brian’s ability to change and adapt as a result of experience or learning. During infancy the brain epxoeriences a rapid growth in synaptic connections. those connections go through synaptic pruning. Although it is easier in children it can happen in adult brains as well.

Kuhn compared the Brian’s of people asked to play 30 mins od super Mario a day to control group. They found an increase of grey matter in Brian areas like the cortex, hippocampus, and cerebellum

Maguire taxi study

Functional recovery

Forms of plasticity can redistribute or transfer functions usually performed by a damaged area to another part of the brain

Ways to repair damage:

axonal sprouting - growth of new nerve endings
Neural unmasking - the unmasking of dormant synapses
Reformation of blood vessels

Case study - EB had virtually his entire left hemisphere of his brain removed at the age of 2 and a half, years of rehab for his language meant that he gradually recovered. At 17 his language was excellent.

Humans echolation is a learned ability from humans to sense their environment from echoes from the sound.

Studies using fMRI have Shein the auditory information is processed by brain regions

Ao3

+preactical application of research - led to neurone habilitation

+reserach supporting plasticity from animal reserach - Huber sewed one eye shut on kittens and found the area of the brain received input from this eye was still active

-plasticity can result in maladaptive consequence - amputees experience phantom limb syndrome

-brain does have a greater propensity to reorganised in childhood and is affected by environmental factors eg years in education

Circadian rhythms

Examples - core body temperature and sleep/wake cycle - once every 24 hours

Sleep wake cycle

endogenous pacemakers - SCN is a tiny bundle of nerves located in the hypothalamus. This sends a message to the pineal gland which produces melatonin which can induce sleep

Exogenous zeitgebers - light and darkness are the external signals that determine when we feel the need to sleep and wake

Ao3

+experimental support - Hae pps only 1 was successful to manage to adjust to the sled up circadian rhythm. Shows that free running rhythms cannot easily be over ridden by external environment

-ev of lamp

-case study

+practical applications

+/- there are individual differences in peoples sleep wake cycle

Ultradian rhythms - more than once every 24 hours

Eg stages if sleep

Stage 1 and 2 Light sleep

Stage 3 and 4 deep sleep

Stage 5 REM

+brain scan support - dementia and klietman monitored sleep of 9 pps and found evidence for the stages of sleep including rem correlating with dreaming

-small sample size

Example - basic rest activity cycle

Move progressively from a state of alertness into a fatigue

Infradian rhythms - less than 24 hours

Menstrual cycle - governed internally by the endogenous pacemakers but it is also possibly affect by external zeitgebers

+mcclintock showed that a females menstrual cycle can be changed by the pheromones if other females

-many confounding variables in synchronised studies

Seasonal affective disorder - depressive disorder with seasonal pattern, the symptoms seem to be triggered in the winter months and is thiugh to be due to the decrease in light. Because it is darker for longer, the lineal gland keeps secreting melatonin, this had a knock on effect to the amount of serotonin (which has been linked with depression)

Ao3

+practical applications for SAD

-though the treatment is only about 60% effective (compared to 30% for fake placebo treatment) - questioning if it is caused by light levels

16 marker - localisation of function

Ao1

localisation - motor, somatosensory, visual, auditory and langague centres: brocas and wernickes areas
Brain in divided into two hemispheres and lateralised -

Lateralisation - some physical and psychological functions are controlled