Biopsychology Flashcards
localisation of function
Specific functions have specific locations within the brain
Role of the motor cortex
generating voluntary movements
Location of the motor cortex
frontal cortex in both hemispheres
How the motor cortex works
Different parts of the motor cortex control different parts of the body which are arranged logically
the motor cortex on one side of the brain control the opposite side of the body
role of the somatosensory area
detects sensory events coming from different regions of the body
somatosensory area location
parietal lobe
How the somatosensory cortex works
Using sensory information for the skin the somatosensory area produces sensations of touch pressure pain and temperature which it then localises to specific body regions
the cortex on one side of the brain receives information from the opposite side of the body
Where is the primary visual centre
Visual cortex in the the occipital lobe
How does visual processing work
Light hits the retina at the back of the eye photoreceptors in the retina send nerve impulses to the brain via the optic nerve terminating in the thalamus which acts as a relay station before passing information to the visual cortex
How does the visual cortex work
Each side of the visual cortex receives information from the opposite side of the visual field
The cortex contains different areas for processing different types of information e.g. colour shape and movement
Where is the primary auditory centre
The auditory cortex within the temporal lobes on both hemispheres
How does auditory processing work
Sound waves are converted into nerve impulses in the cochlea of the ear. These impulses travel via the auditory nerve to the brain stem for basic decoding (e.g. intensity and duration) then the thalamus as a relay station and for further processing before proceeding to the auditory cortex in the brain.
How the auditory cortex works
The sound has largely been decoded by this point but in the cortex it is recognised and may result in an appropriate response
What are the 2 primary language centres
Broca’s and Wernicke’s areas
Where is Broca’s area
Posterior portion of the left frontal lobe
Function of Broca’s area
Speech production
How Broca’s area was discovered
Treated patient who could only say “tan” but could understand spoken language
Brain was studied and he had a lesion in his left frontal lobe
8 other patients with a similar language deficits were studied and had the same damage.
Patients with legions in the same area on the right did not have the same problems
Where is Wernicke’s area
Posterior left temporal lobe
Function of Wernicke’s area
Understanding language
Localisation of function evaluation - evidence from neurosurgery
Neurosurgery is a last resort for treating some mental disorders, targeting specific areas of the brain which may be involved e.g. cingulotomy’s for OCD where the cingulate gyrus is isolated
Dougherty reported on 44 cingulotomy patients and 32 weeks post surgery 30% had a successful response.
suggests behaviours associated with mental disorders may be localise
Localisation of function evaluation - communication over localisation
It may be more important how areas of the brain communicate rather than which specific regions control specific processes
Although different regions may have specialist functions to work they must interact with each other e.g. loss of ability to read resulted from damage to connections between visual cortex and Wernicke’s area.
Suggests complex behaviour are built up as stimulus enters the brain and moves through different structures before a response, damage to connections may resemble damage to localised region
Localisation of function evaluation - brain scans
Petersen et al (1988) used brain scans to demonstrate how Wernicke’s area was active during a listening task
Localisation of function - distributed function of learning
Lashley (1950) removed areas of the cortex between 10%-50% in rats that were learning the route through a maze. No area was proven to be more important than any other in terms of the rats ability to learn the route. Learning seemed to require every part of the cortex
What is hemispheric lateralisation
Some mental processes in the brain are mainly specialised to either the left or right hemisphere
How are the 2 hemispheres of the brain connected
A bundle of nerve fibres called the corpus callosum
Who are split brain patients
People who have had their corpus callosum cut
Often performed to treat very severe epilepsy
As the corpus callosum is cut the two hemispheres cannot interact and information has to be processed within the hemisphere it was received in
Sperry and Gazzaniga - procedure
Studied split brain patients to test the abilities of each hemisphere one at a time
patient fixate on a dot in the centre of a screen
Information was presented to the left or right visual field then asked to make responses with the left or right hand without being able to see what their hands were doing
Sperry and Gazzaniga - findings
left hemisphere is responsible for speech and language
Right hemisphere responsible for visual-spatial processing
Example - picture of dogs flashed on the right visual field patient would know they saw a dog as the left hemisphere processes information from the left and is responsible for speech if flashed to the left visual field the patient would say they see nothing as the right hemisphere processes the left visual field but does not have a language centre so cannot say what it saw
