Biopsych 2 Flashcards
What is localisation of function?
The principle that specific functions have specific locations within the brain
What is Franz galls theory of phrenology?
What did Pierre flourens do?
The study of the structure of the skull to determine a persons character and capacity
Used animal experiments to demonstrate main divisions of the brain were responsible for different functions.
Since the 19th cent, techniques have grown considerably
What is the motor cortex:
Role
Location
Responsible for generation of voluntary movements
Located in frontal lobe along pre central gyrus
Motor cortex on each side of brain- left responsible for muscles on right vice versa
Diff parts of motor cortex control diff body parts and they are logically offered (eg part that control foot is next to part that controls leg)
What is the somatosensory cortex?
Located?
Detects sensory events in diff parts of the body
Located in parietal lobe along the post central gyrus
Uses sensory info from skin to produce sensations of touch pressure pain temp and localises it to specific regions of body
Like motor cortex, one on each side and cross wired
What is the post central gyrus?
Area of cortex dedicated to processing of sensory info related to touch
where is the primary visual center of the brain?
where does visual processing actually begin? then where does it go?
in the visual cortex in the occipital lobe. visual cortex spans both hemispheres (left receives info from right vf vice versa)
begins in retina where light strikes photoreceptors. nerve impulses are then transmitted to brain by optic nerve
some nerve impulses then travel to parts of brain to be involved in coordination of circadian rhythms but most terminate in thalamus which passes info onto visual cortex
what is the auditory center? where is it? describe the auditory pathway
concerned with hearing
mostly lies within temporal lobes on both sides in the auditory cortex.
pathway starts in cochlea where sound waves are converted to nerve impulses which travel to auditory cortex by auditory nerve
first stop is brain stem where basic decoding happens, then thalamus where further processing occurs. ends at auditory cortex which recognises sound and generates response
what are the 2 language centers?
broca’s area and wernicke’s area
what is broca’s area?
posterior portion of left frontal lobe
critical for speech production
discovered by paul broca due to patient who could only say ‘tan’ but could understand speech. also studied others with similar problems and lesions in left frontal hemisphere
what is wernicke’s area?
posterior portion of the left frontal lobe
critical in speech understanding
his patients could speak but not understand
what did wernicke propose?
language involves separate motor and sensory regions.
motor region in brocas is close to area that control mouth, tongue, vocal cords.
sensory region in wernicke’s is close to part of brain responsible for auditory/visual input
there is a neural loop between brocas and wernickes
evaluation of localisation of function and language centres
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not everyone agrees functions are localised eg equipotentiality theory (lashley 1930) suggests basic motor and sensory functions are localised but more complex arent. says intact areas of cortex can takeover responsibilities following injury. says effect of damage is determined by extent not location
research suggests how areas communicate is more important that which region controls specific process. wernicke claimed areas are interdependent. eg french neurologist described case where loss of ability to read led to damage to connection between visual cortex and wernickes area. suggests complex behaviours move through diff structures before response produced. damage to connection between any 2 points in this process leads to impairments similar to damage to localised brain region for that specific function
individual diff- eg bavelier et al 1997 did silent reading study and found variability in patterns of activity between people. found activity in right temp lobe, left front, temp, occip lobes. gender differences- harasty et al 1997 found larger brocas and wernickes in women due to greater use of language
language may not be confined to brocas- bronkers et al 2007 examined lesions using MRI and found other areas may have contributed to reduced speech. significant as lesions in brocas usually cause temporary disruption- suggests speech is complex and network not localised
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support for language centres from aphasia studies eg brocas and wernickes. expressive aphasia- cant produce language shows brocas is important for speech. receptive aphasia- cant understand language shows wernickes is important in comprehensive
case study evidence- Gage, Tan, HM
what is hemispheric lateralisation?
the fact that 2 halves of the brain arent entirely alike and each hemisphere has functional specialisms
how are the 2 hemispheres attached? what does this mean?
the corpus collosum ( a bundle of nerve fibers that connect the 2 halves)
means info can be sent from one half to other and we can for example, talk about things experienced in right hemisphere despite left for language
what is a commisurotamy?
cutting through the corpus collosum as treatment for severe epilepsy.
prevents violent electrical activity from crossing from one hemisphere to another. known as split-brain patients
