Localisation

• Broca's area:

  • area in frontal lobe, left hemisphere, related to speech production. Fedorenko 2012, found 2 regions of Broca's area, one selectively language involved, and one responding to cognitive tasks like maths problems
• Wernicke's area:

  • area in left posterior temporal lobe, important in comprehension of language
• Localisation of function:

  • the belief that specific areas do a specific cognitive function
• Motor cortex:

  • responsible for generation of voluntary motor movements, located in frontal lobe on both hemispheres, on precentral gyrus, each side of motor cortex controls opposite side of body (contralateral)
• Somatosensory cortex:

  • processes input from sensory receptors in the body that are sensitive to touch. Located in postcentral gyrus in parietal lobe, both hemispheres, contralateral control
• Visual centre:

  • in visual cortex in occipital lobe, in both hemispheres. Begins in retina, travels to visual centre through optic nerve. Right side receives input from left visual field, and vice versa
• Auditory centre:

  • in temporal lobe in both hemispheres, in auditory cortex. Starts in cochlea, through auditory nerve, to auditory centre. Decoded at each stage of journey
• AO3

  • Lashley 1930, believed basic functions like motor and sensory were localised, but not higher mental functions. Claimed when one brain area damaged, other areas would take responsibility to help it still function normally. Effects of damaged brain more about the extent than location
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  • Wernicke claimed while areas were localised, they were all interdependent and interacted with each other. Joseph Dejerine 1892, described patient who lost ability to read due to damage in the connection between the visual cortex and Wernicke's area
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  • Expressive (Broca's) aphasia impaired ability to produce language, usually due to damage of Broca's area. Receptive (Wernicke's) aphasia impaired ability to understand/extract meaning from language. Usually due to damage in that area. Supports the importance each role seems to l,ay in these functions
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  • Bavelier 1997, found brain activation patterns when reading differed across individuals, with activity in the right temporal lobe, and the left frontal, occipital, and temporal lobe all being activated at some point. Other studies showed gender differences in brain areas associated with language. Harasty 1997, found women have proportionally larger Broca and Wernicke's areas
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  • Dronkers 2007, re-examined 2 Broca patients (Louis Leborgne/Tan, and Lazare Lelong). Used MRI to find other areas that had been damaged apart from Broca's are, suggesting lesions in other areas can produce same aphasia, questioning localisation