Explain one study related to localization of function in the brain. (8)

Explain (8) – Detailed account including reasons or causes. Command Term

Certain areas of the brain is responsible for specific functions such as behaviour, emotions, thoughts and language. Thus, damage to certain areas of the brain may result in sever loss of function for the individual. What is localization of function?

Occipital lobes- portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields. Parietal lobes- portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position. Frontal lobes- portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments. Temporal lobes- portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear. Parts of the brain- Four Main Lobes

Hemispheres Left Hemisphere The left brain is the logical brain responsible for words, logic, numbers, analysis, lists, linearity and sequence. It controls the right side of your body. Right Hemisphere The right brain is the creative brain and is responsible for rhythm, spatial awareness, colour, imagination, daydreaming, holistic awareness and dimension. It controls the left side of your body.

Broca's Area In the frontal lobe, in the left hemisphere; directs muscle movements involved in speech Wernicke's area In the left temporal lobe; involved in language comprehension and expression Damage to these areas may result in aphasia Impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (they can speak with normal grammar, syntax, rate, and intonation, they cannot express themselves meaningfully using language). Other Areas

Harlow – Phineas Gage (1849) Broca – Tan (1861) Milner – HM (1966) Studies that support this LO

He was a young railroad worker in 1848 who had an accident at work. He was forcing gun powder into a rock with a long iron rod when the gun powder exploded. The iron rod shot through his cheek and out the top of his head, resulting in substantial damage to his frontal lobe. Incredibly, he did not appear to be very hurt. His memory and mental abilities were intact, and he could speak and work. However, his personality completely changed. Prior to the accident, he displayed a pleasant demeanor, but afterward he became ill- tempered and dishonest. He lost his job and ended up working as an exhibit at fairs. Phineas Gage 1849

Observations Change in personality Harlow described him as having little restraint, using extremely rude language, and making grand plans for the future, which would be instantly replaced with others. Localization of function Harlow’s study suggests that the frontal lobe may be responsible for controlling personality Phineas Gage 1849

Paul Broca (1861) was a psychologist who carried out a longitudinal study of a specific case where Tan, a patient was unable to speak, but could understand conversations. He was unable to say anything except for the word 'tan'. Although he was mute, he was able to understand simple conversations. After Tan's death, Broca performed an autopsy and found that the left frontal lobe of Tan's brain was severely damaged. Tan 1861– Broca’s Aphasia

Conclusion Broca came to the conclusion that the brain was localized - specific parts of the brain performed particular tasks that it was specialised to perform. Broca hypothesized that the left frontal lobe of the brain was responsible for tasks such as producing speech (locution) as well as deducing meaning from complex language, emotions, and analysis of syntax. The effects of damage to this part of the brain can most easily be observed in the speech of stroke victims, many of whom are temporarily or permanently unable to produce language, a condition known as Broca’s aphasia. Broca was one of the first psychologists to suggest that the brain was localized. Tan 1861– Broca’s Aphasia Paul Broca

Damage to the hippocampus and amnesia Scoville and Milner (1957) described the case of H.M. who fell off his bicycle when he was 7 years old, injuring his head. He began to have epileptic seizures when he was 10. By the age of 27 the epileptic attacks prevented him from living a normal life. Scoville performed an experimental surgery on H.M.’s brain to stop the seizures. Specifically he removed parts of HM's temporal lobes (part of his hippocampus along with it).The seizures stopped but H.M. suffered from amnesia for the rest of his life. H.M. (Henry Gustav Molaison) 1966

H.M.’s memory: H.M. could no longer store new memories (anterograde amnesia). Most of his memories from before the operation remained intact (partial retrograde amnesia). He could not transfer new semantic and episodic memories (explicit memories) into LTM. He could form new long-term procedural memories (implicit memories). He was able to carry on normal conversations (i.e. had some capacity for working memory) but he would forget what the conversation was about immediately. H.M. (Henry Gustav Molaison) 1966 Henry Gustav Molaison

The hippocampus play a critical role in converting memories of experiences from STM to LTM (the permanent store). H.M. was able to retain some memories for events that happened long before his surgery. This indicates that the medial temporal region with the hippocampus is not the site of permanent storage in itself. It rather seems to play a role in how memories are organized and then stored elsewhere in the brain. The fact that H.M. and other people with amnesia have deficits in some types of memories but not in others is taken as evidence that the brain has multiple memory systems that are supported by distinct brain regions. The case study of H.M. provides information on how particular brain areas and networks are involved in memory processing. H.M. (Henry Gustav Molaison) 1966