Localisation Of Brain Function And Hemispheric Lateralisation Flashcards
Define loc of brain function
Specific areas of the brain associated with different functions
The case of phineas gage
Brain trauma that informed understanding of hemispheric lateralisation
Tamping iron went under cheekbone, through back of eye socket and through top of his forehead
Recovered psychically but psychologically he became more hostile, used vulgar language
Advantage and disadvantage of case study
+ detailed and in depth
- lacks generalisability
Hemispheric lateralisation definition
Division of functions between the two asymmetrical hemispheres
Brain is contralateral in most people
Summary of the left hemisphere responsibilities
Language processing
Broca’s: lesion in the frontal love of the left hemisphere, posterior region
Speech production
Wernicke’s: understanding language, left temporal lobe
Summary of the right hemisphere responsibilities
Heller and Levy: photo of face split in half of one smiling and one neutral, emotion displayed on left hand side recognised by ppt as the right hem.
Halligan et al: if ppt is asked to ID small detail in pic, there is a greater activity in left but holistic image processed by right
Location of the motor cortex and function
Frontal lobe
Complex movements rather than reflex eg cycling, dancing and writing
Communicates with motor neurones to bring movement sending messages to muscles via brain stem and spinal cord
Somatosensory centres location and function
Sensations of the body such as touch, pain, pressure etc
Directly behind motor cortex in parietal lobe
More neuronal connections in touch sensitive areas of the body e.g. Sensations from the face
Visual centres
Primary is the visual cortex which processes visual info
Receives info from opposite side
Located in occipital lobe at the back of the brain, spans both hemispheres
Contains areas processing different types of visual info e.g. Colour, shape or movement
Steps of processing visual info
1) light enters eyes, received by retina
2) hits photo receptors at back of retina
3) nerve impulses travel down the optic nerve to brain, received by thalamus
4) thalamus acts as a relay station, transmitting info the visual cortex
Visual perception area
Area V1 in visual cortex
If damaged leads to ‘blind sight’ condition in which individuals report no vision but able to locate objects
Suggests some processing of visual cortex is not conscious as respond to stimulus not consciously seen
Overgaard et al
Women with ‘blindsight’ with damage to visual cortex found she could detect a letter in the screen reporting ‘awareness of something’
Statistically significant relationship between awareness of stimuli and accuracy
Investigating blindsight
Use patients who are blind in one side of visual field
Stares @ fixed point and asked to ‘guess’ what is on the blind side, equip may monitor brain activity and involuntary responses
Ppts shown images of ppl expressing emotion correctly guessed and facial muscles matched the kind of emotions
Auditory centres
Primary auditory cortex concerned with hearing and processing sound info from both ears
Info of what sound is and located
Two primary auditory cortices, one in each hemisphere within temporal lobes
Steps of auditory processing
1) auditory pathways begin in cochlea in inner ear
2) sound waves converted to nerve impulses which travel via the auditory nerve to auditory cortex in the brain
3) on journey, nerve impulses pass through the brain stem and thalamus
