Localisation of Function in the Brain Flashcards
(7 cards)
What is Loc of Func in the brain?
- Refers to the principle that specific functions (speech, memory, hearing etc) have specific location within the brain
What occurs in the motor and somatosensory areas?
Motor Cortex
- Responsible for generation of voluntary movements
- Located in the frontal lobe in a region known as the Precentral gyrus
- Both hemispheres have a motor cortex where they both control the opposite sides
- Regions are arranged logically next to each other
fingers, hand, arms, head etc
Somatosensory Cortex
- Detects sensory events
- Located in the parietal lobe in an area known as the
postcentral gyrus
- Postcentral gyrus is the area that processes sensory info related to touch
- Both hemispheres have a somatosensory cortex and work the opposite sides
What occurs in the Visual and Auditory centres?
Visual centre
- Located in the Visual Cortex in the occipital lobe of the brain despite first processing beginning at the retina
- Nerve impulses from the retina are transmitted to the brain via optic nerve and terminate at the thalamus
- Visual cortex spans both hemispheres with each side working the opposite sides
Auditory Centre
- Concerned with hearing and most area lies within the temporal lobe in the auditory cortex
- Begin in the cochlea then converted to nerve impulses then up the brain stem then the relay station at the thalamus last stop is auditory cortex
What is Broca’s area?
- Critical for speech production
- Broca studied o patients all of whom had similar language deficits along with a lesion in their left frontal hemisphere
- Patients with same lesions in right hemisphere did not have the same language deficit
- Led to the identity of a language centre in the posterior portion of the frontal lobe of the left hemisphere
What is Wernicke’s Area?
- Discovery of another area specifically for understanding language
- Posterior portion of the left temporal lobe
- Patients with lesions in Wernicke’s area could speak but not understand language
- Language involved separate motor snd sensory regions located in different cortisol regions
- Motor region in Wernicke’s area is close to regions of the brain for auditory and visual input
- A neural loop known as the arcuate fascicles running between Broca’s area and Wernicke’s area
What are 2 strengths to Localisation of the brain?
Support from Aphasia research
- Inability/Impaired ability to understand or produce speech as a result of brain damage
- Expressive Aphasia (Broca’s) impaired ability to produce language usually because of brain damage
- Receptive Aphasia (Wernicke’s) impaired ability to understand language or extract meaning from spoken or written words usually due to a stroke
Demonstrates important role played by both brain regions responsible for comprehension/production language
Treating Mental illness
- Neurosurgery to treat extreme cases of OCD or depression
- Report on 44 OCD patients who had undergone a cingulotomy whereby a piece of the brain is removed
- Post 32 weeks 1/3 had met the criteria for successful reposes to the surgery and 14% for partial response
Success like this suggests symptoms and behaviours associated with serious metal disorders are localised
What are 2 limitations of localisation of the brain?
Challenges of Plasticity
- Cortical remapping or plasticity happens after brain injuries or damage and the brain rewires itself or reorganises itself to recover lost functions
- The action of ‘chipping in’ allows neurological action to be achieved
Refuting the idea that certain functions are localised
Holism in the brain
- Studies suggest that cognitive functions such as learning are not localised but distributed across the brain
- Lashley removed parts of the cortex in rats learning a maze and no area showed more signs of learning than other areas meaning that it is not just one part of the brain but spread out
Suggests that learning is too complex to be localised and requires whole brain
