localisation of function

• P: not all researchers agree with the view that cognitive functions are localised in the brain.

  E: a conflicting view is the equipotentiality theory. Lashley believed basic motor and sensory functions were localised, but higher mental functions were not. He claimed that intact areas of the cortex could take over responsibility for specific cognitive functions following injury to the area normally responsible for that function. effects of damge to the brain would be determined by the extent rather than the location of the damage
• link for equipotentiality

  L: this view has received some support from the discovery that humans were able to regain some of their cognitive abilities following damage to specific areas of the brain
• P: evidence for the different functions of broca's and wernicke's areas in language production and understanding comes from the discovery that damage to these different areas results in different types of aphasia

  E: expressive aphasia is an impaired ability to produce language. this is caused by brain damage in broca's area. receptive aphasia is an impaired ability to understand language, an inability to extract meaning from spoken or written words. this form of aphasia is the result of damage in wernicke's area
• link for aphasia studies

  L: this demonstrates the important role played by these regions in different aspects of language.
• P: dronkers re-examined the preserved brains of two of brica's patients, leborgne and lelong. they used modern high resolution brain MRI imaging in order to identify the extent of any lesions in more detail

  E: MRI findings revealed that other areas besides broca's area could also have contributed to the patients reduced speech abilities. this finding is significant because although lesions to broca's area alone can cause speech disruption, they dont usually result in severe disruption of spoken language
• link for dronkers

  L: this study suggests that language and cognition are far more complicated than once thought and involve networks of brain regions rather than being localised to specific areas