localisation of function Flashcards
motor cortex
responsible for generation of voluntary movements
located in frontal lobe of brain in both hemispheres controlling muscles on opposite side of the body
somatosensory cortex
detects sensory events arising from different regions of body
located in parietal lobe where processing of sensory info related to touch occurs
using sensory info from the skin it produces sensations of touch, pressure, pain and temp which it then localises to specific body regions. both hemispheres have somatosensory cortex, with cortex on one side of brain receiving sensory info from opposite side of body
visual centres
primary visual centre in brain is located in visual cortex in occipital lobe of brain.
auditory centres
lies within temporal lobes on both sides of brain where auditory cortex is
auditory pathways begin in cochlea of inner ear, where sound waves are converted to nerve impulses which travel via auditory nerve to auditory cortex
broca’s area
broca - patient Tan could understand spoken language but was unable to speak or express thoughts in writing
however, neuroscientists have found evidence of activity in brocas area during cognitive tasks that don’t involve language
fedorenko et al - discovered 2 regions of broca’s area: one involved in language and the other in responding to many demanding cognitive tasks
wernicke’s area
involved with understanding language
wernicke - language involves separate motor and sensory regions. sensory region located in wernicke’s area is close to regions of brain responsible for auditory and visual input.
input from these regions is transferred to wernicke’s area where it’s recognised as language and associated with meaning
neural loop running between broca’s and wernicke’s area, at one end lies broca’s area and at the other lies wernicke’s area
evaluation - communication may be more important than localisation
research suggests how brain areas communicate with each other is more important than which specific brain regions control a particular cognitive process
dejerine - case study where loss of ability to read resulted from damage to connection between visual cortex and wernicke’s area
suggests complex behaviours like language are built up gradually as a stimulus that enters the brain then moves through different structures before response is produced. damage to connection between any 2 points in this process results in impairments that resemble damage to localised brain region associated with specific function
evaluation - support for language centres from aphasia
evidence for different functions of broca’s and wernicke’s areas in language production and understanding comes from discovery that damage to these different areas results in different types of aphasia
broca’s aphasia - impaired ability to produce language and is mostly caused by brain damage in broca’s area
wernicke’s area - impaired ability to understand language, an inability to extract meaning from spoken or written words and is usually due to damage of wernicke’s area
demonstrates important role played by these brain regions in different aspects of language
evaluation - language production may not be confined to broca’s area alone
dronkers et al - re-examined preserved brains of 2 of broca’s patients and using MRI in order to identify the extent of any lesions in more detail
MRI findings - other areas could also result in reduced speech abilities - although lesions in broca’s area alone can cause temporary speech disruption, they don’t actually result in severe disruption of spoken language
suggests language and cognition are far more complicated than once thought and involve networks of brain regions rather than being localised to specific areas
