Localisation of function in the brain Flashcards
Holistic Theory (Localisation)
Paul Broca and Karl Wernicke discovered that specific areas of the brain are associated with particular physical and psychological functions
-Before this, scientists were supporting the holistic theory of the brain- that all parts were involved in thought and action processes
-They stated that if a certain area of the brain becomes damaged through illness or injury, the function associated with that area will also be affected
Hemispheres of the brain and the cerebral cortex
Some functions of the brain are controlled by a particular hemisphere- lateralisation
Activity by the left-hand side of the body is controlled by the right hemisphere and vice versa
The outer layer of the hemispheres is called the cerebral cortex which covers the inner parts of the brain
Motor Area of the brain
Back of the frontal lobe which controls voluntary movement in the opposite side of the body- damage to this area may result in loss of control over fine movements
Somatosensory Area
-Front of both parietal lobes
-separated from the motor area by the central sulcus
-its where sensory info from the skin such as touch, heat, pressure is represented.
Visual Area
-In the occipital lobe at the back of the brain
-each eye sends info from the right visual field to the left visual cortex and vice versa. This means that damage to the left hemisphere can produce blindness in part of the right visual field of both eyes
Auditory Area
-housed in the temporal lobe
-analyses speech-based info
-damage may produce partial hearing loss, worse damage worse loss.
-damage to Wernicke’s area can affect the ability to comprehend language
Language area of the brain
-language is restricted to the left side of the brain for most people
-Paul Broca discovered a small area in the left frontal lobe responsible for speech production. Damage to this can cause Broca’s aphasia which makes speech slow, laborious and lacking in fluency. I.e Broca’s patient ‘Tan’- the only word he could say
-Karl Wernicke was describing patients who had no problem producing language but severe difficulties understanding it, the speech they produced was fluent but meaningless.
-He identified Wernicke’s area in the left temporal lobe as being responsible for language comprehension which would result in Wernicke’s aphasia when damaged
A03- Brain scan evidence of localisation
-Lots of evidence proving support for the idea that many neurological functions are localised
-Peterson et al 1988 used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task, suggesting that these areas had different functions
-Tulving et al 1994 revealed that semantic and episodic memories reside in different parts of the prefrontal cortex.
-There is not a number of highly sophisticated and objective methods for measuring activity I the brain which provide scientific evidence for localisation
A03- Phineas Gage 1848
-Supports localisation of function
-He suffered an accident when a large mental pole was forced up through this head following an industrial accident, removing most of his left frontal lobe
-His personality changed and became short-tempered and rude
-Was suggested that mood regulation may be the responsibility of the frontal lobe
Issues and Debates- Idiographic Approach, very subjective
Extraneous Variables
A03- Neurosurgical evidence
P= There is neurosurgical evidence
E=Lobotomy. This severed connections in the frontal lobe in an attempt to control aggressive behaviour
Another example is that this type of neurosurgery is still used today for cases of OCD and depression. Found that 1/3 of patients responded well to the surgery
E-This suggests that neurosurgery provides support for brain localisation
Therefore the success of procedures like this strongly suggest that symptoms and behaviours associated with serious mental disorders are localised
