BIOPSYCH ( lateralisation and split-brain research)

Question 1

Define lateralisation

Answer 1

refers to the idea that the two hemispheres of the brain function differently and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.

Question 2

Outline the key mental processes that the left hemisphere and right hemisphere are responsible for

Answer 2

Left hemisphere - often responsible for language , analytical and logical tasks.
Right hemisphere - Often involved in spatial abilities, face recognition , and some aspects of emotion.

Question 3

both hemispheres are contralateral what does this mean and give an examples

Answer 3

Left hemisphere controls the right side of the body. Right hemisphere controls the left side of the body .

Information from the left visual field goes to the right hemisphere , and vice versa.

Question 4

What is a split brain surgery?

Answer 4

Commissurotomy is a surgical procedure in which the corpus callosum ( which connects both hemispheres) is severed. Used to treat severe epilepsy by preventing seizures from spreading across hemispheres.

Question 5

Outline the key research into Split brain ( aim , procedure , findings)

Answer 5

Aim : to investigate the extent to which the two hemispheres are specialised for certan functions.

Procedure : Participants who had gone through surgery took part. Participants were asked to take part in tasks like matching objects or drawing using one hand. Visual stimuli were presented to one visual field only.

Findings : when asked to draw the left hand ( right hemisphere) produced better drawings even if right handed. When presented with an image in the left visual hemisphere , patients could not say what they saw but could select matching object with left hand.

Conclusions : there is hemispheric lateralisation of function. Language is typically lateralised to the left hemisphere. The right hemisphere is better at visual-motor tasks , recognising patterns and spatial processing.

Question 6

Evaluate Research into Split brain

Answer 6

STRENGTHS :

Sperry used highly controlled procedures. This allowed for precise conclusions about the role of each hemisphere to be drawn about the role of each hemisphere especially in language & visual-spatial tasks.

Real world application : understanding lateralisation helps clinicians predict which cognitive functions may be affected by brain damage or surgery esp in stroke patients or those undergoing neurosurgery. It enhances treatment planning and recovery strategies eg. speech and language therapy.

LIMITATIONS

Limited generalisability : Research involved a small group of participants ( fewer than 20) , many of whom had long-term severe epilepsy and undergone surgery. Their brains may have been functionally abnormal making it difficult to generalise findings to the wider population.

Oversimplified : the idea of strict lateralisation ( left= language , right= creativity) is now seen as too reductionist as most tasks involve integration between hemispheres. This neglects the brain’s plasticity and the dynamic interplay between hemispheres during complex tasks eg. FMRI show both hemisphere activity during tasks like language.

extraneous variables - varied disconnection ,lack of valid control group/ drug therapy

contradictory evidence - patient J.W could speak using the right hemisphere