biopsychology A03 + key A01 Flashcards
motor cortex
- voluntary muscle movements
- frontal lobe in precentral gyrus
- both hemispheres
somatosensory cortex
- sensory input from skin, muscles, joints. produces sensations of pressure, pain and temp and localises to regions of the body
- parietal lobe
- both hemispheres receive input from opposite side of body
visual cortex
- associated with vision such as colour, shape, movement. info from eyes (retina) travel to here
- occipital lobe
- both hemispheres receiving info from opposite visual field
auditory cortex
- hearing, process sound, volume, pitch and location of sound. info from inner ear travel to auditory cortex via nerve impulses
- temporal lobe
- in each hemisphere
wernickes area
- damage to this area meant inability to understand language and not forming coherent sentences. could utter words but they lacked meaning
- left temporal lobe
- left hemisphere
brocas area
- damage meant understanding of language but an inability to speak or express thoughts in speech or writing
- frontal lobe
- left hemisphere
localisation
principle that specific functions e.g hearing, memory etc have specific locations within the brain
lateralisation
each hemisphere has functional specialisms e.g L hemisphere dominant for language
how do brocas and wernickes interact to produce language
1 sensory region picks up auditory and visual input
2 info transferred via audio/visual cortex
3 wernickes area- recognises lang. and associates with meaning
4 brocas area- identifies what speech needs to be produced
5 info transferred via motor cortex
6 SPEECH
strengths of localisation of function
- Peterson, used brain scans to show wernickes area activated during a listening task and brocas area activated during a reasoning task showing parts of brain for different functions
- practical applications for people who have had strokes. the symptoms can suggest what part of the brain is damaged and this can be helpful in formulating treatments
weaknesses of localisation of function
- counter research by Danelli into EB. had most of L hemisphere removed due to a tumour at age 2 and all language capabilities were lost. at age 17 EB had undergone intensive rehabilitation and his language was comparable to normal as the R hemisphere had compensated for the loss of the L hemisphere. brain plasticity can occur
- methodological problems as research is normally case studies who have suffered wounds, illnesses, tumours or strokes. their brains are specific to them and idiosyncratic. not generalisable to other individuals with undamaged brains
3 main findings of sperry research
1 describing what was seen- word at R visual field was immediately reported as L hemisphere for lang.
2 recognition by touch- L hand behind a screen, word presented to R hemisphere and correct object could be selected and named but could not explain why they selected this. shows R hemisphere can identify basic nouns
3 matching faces- picture presented to R hemisphere was consistently selected and L hemisphere was ignored when asked to match a face from a series of others. L hemisphere was dominant in verbal description. shows R hemisphere dominant for matching faces
strengths of split brain research
- supportive research in ‘normal’ functioning brains. rasmussen and milner found L hemisphere more concerned with language and R hemsiphere concerned with spatial and artistic functioning showing lateralisation even when corpus callosum present
- methodology used in sperry research as there were high levels of control. stimulus only presented for 200 millseconds to remove tendency of pp to move their eyes towards the stimulus so only the visual field intended to be tested was assessed so only one hemisphere looked at at one time. allows sperry to carry out variations and increases replicability
weaknesses of split brain research
- lack of ecological validity as does not reflect how pp would use their brain in everyday life as sperry ensured only one visual field was measured at one time. it is likely the would use both eyes to compensate for the cut corpus callosum so it is difficult to make generalisations
- counter evidence by Turk et al. found JW was able to speak out of R hemisphere and can now use either the left or right. plasticity can occur where damaged parts are
plasticity
ability of brain to adapt and change synapses, pathways and structures due to various experiences
ways functional recovery occurs
1 axon sprouting- axons of surviving neurons grow new branches making synapses in damaged area
2 denervation super sensitivity- axons that do a similar job become aroused to a higher level to compensate for those that are lost
3 recruitment of homologous areas- opposite side of brain performs the specific task
strengths of plasticity and functional recovery
- danelli and EB.
- practical applications as therapy can be used to gradually retrain the brain so it can reorganise. can include movement therapy or electrical stimulation of the brain
weaknesses of plasticity and functional recovery
- not always a smooth recovery, requires a lot of effort for patient to complete simple tasks so they may become fatigued
- gender can affect extent to which plasticity occurs. ratcliffe examined 325 patients with brain trauma who were recieving rehabilitaion. women outperformed men on cognitive tasks such as attention, working memory and language. men outperformed women on visual analytical skills. but women made a better recovery than men. perhaps because they have stronger connections between the corpus callosum
FMRI
- Functional magnetic resonance imaging
- records enersy released from haemoglobin
- active parts need more O2
- moving 3D picture of activity 1 sec after real time
strengths of fmri
- non invasive and does not use radiation like pet scans so ethical
- objective no researcher bias so is reliable
weakness of fmri
-impractical, expensive, requires person to be completely still so not suitable for all people, uncomfortable and noisy
EEG
- electroencephalogram
- electrical activity in brain
- action potentials or nerve impulses
- electrodes on scalp
- electrical signals on graph
- measure neurological abnormalities e.g epilepsy or sleep disorders
strength of eeg
-accuracy, real time recording accurately measures task or activity
weaknesses of eeg
- not specific enough, cannot pinpoint exact source of activity and cannot differentiate between adjacent locations
- surface level measurement. detects activity in superficial regions of brain so cannot reveal what is going on deeper regions like hypothalamus or hippocampus
ERP
- event related potentials
- similar to eeg as measures electrical activity
- statistical averaging techniques to filter out extraneous brain activity leaving only those that relate to task of interest
- stimulus presented and electrical responses looked at
strengths of ERP
- accuracy as continuous measurement so preferrable to fmri
- reduces demand characteristics, does not require individual to give a response reducing social desirability bias as no conscious control over brain activity. a particular word in a sentence can be processes using erp at the time the word is presented and this can not be controlled
weakness of erp
-surface measurement, only detect neural activity of a certain strength so activty deeper e.g amygdala cannot be measured
post mortem
- brain of deceased in people who have rare disorders, unusual deficits in mental processes to see where damage has occurred
- allows causes of behaviour to be established
- establishes links between psychiatric disorders e.g schizophrenia and depression
strength of post mortem
- full access to whole brain, detailed analysis not possible through other non invasive methods, deepr areas can be examined
weaknesses of post mortem
- lack of control, confounding variable such as cause of death, time between death and post mortem and drugs taken before death. comparisons to controls may not be valid
- retrospective as issues establishing causation. cannot follow up on anything that arises and observed damage may not be as a result of the suspected cause
