AO1 Localisation of function in the brain and hemispheric lateralisation: motor, somatosensory, visual, auditory and language centres; Broca's and Wernicke's areas. Split brain research. Plasticity and functional recovery of the brain after trauma.

Localisation

The theory that specific areas of the brain are associated with particular physical and psychological functions.

Motor cortex

Located at the back of the frontal lobe and is responsible for the generation of voluntary motor movements.

Somatosensory cortex

Located in the parietal lobe, close to the motor area. This produces sensations of touch, pressure, pain and temperature, which it localises to specific body regions.

Visual centre

Located in the visual cortex in the occipital lobe. The visual cortex contains different areas for colours and shapes

Auditory centre

Located in the temporal lobe in both hemispheres, and is concerned with hearing.

Broca’s area

Located in the left frontal lobe, and is essential for speech production.

Wernicke’s area

Located in the left temporal lobe, and is responsible for the recognition and processing of language.

Lateralisation

The dominance of one hemisphere of the brain for particular physical and psychological functions.

Difference between the hemispheres

The presence of the language areas which are mainly found on the left hand side.

Sperry’s split brain research method

An image or word would be projected to the patient’s right visual field which is processed by the left hemisphere, and the same or different could be would be projected on the left visual field.

Sperry’s split brain research findings

In the normal brain the corpus callosum would share the information between both hemispheres giving a complete picture of the visual world. However, a split brain patient’s brain wouldn’t convey information from one hemisphere to here. When shown an object to the right visual field, the patient could easily describe what was seen. However, if shown to the left visual field the patient couldn’t describe what they saw and said there was nothing there.

Sperry's research into split brain concluded

The language centres are in the left hemisphere, and the patients inability to describe what was in the left visual field was because of a lack of language centres in the right hemisphere.

Brain plasticity

The brains ability to change and adapt as a result of experience. Young children show more plasticity than older adults.

Three ways neural plasticity occurs after trauma

Axonal sprouting, neuronal unmasking and recruitment of similar areas on the opposite side of the brain to perform specific tasks

Axonal sprouting

The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways

Neuronal masking

Dormant synapses in the brain are reactivated