Revision biological bases.docx

**Year 12 Psychology Unit 4 Revision for test Monday August 5, 2024** **Task 6: Biological Bases of Behaviour:** text year 11 Chapter 2- in booklet form **Brain structures and functions:** - The 4 hemispheres and their main functions p14-15 - The limbic system structures and functions- thala...

**Year 12 Psychology Unit 4 Revision for test Monday August 5, 2024** **Task 6: Biological Bases of Behaviour:** text year 11 Chapter 2- in booklet form **Brain structures and functions:** - The 4 hemispheres and their main functions p14-15 - The limbic system structures and functions- thalamus, hypothalamus, hippocampus, p12-13 amygdala -- google search - Corpus callosum p13 5 Modern methods of studying the brain: Brain imaging techniques -- EEG, CAT, MRI, fMRI, PET - For the imaging techniques -- explanation of how it works, what it's used for, the strengths and weaknesses. - For case studies: a description of the case study, and an evaluation of how it's contributed to our understanding of the brain. Methods of studying the brain 1848-present with case studies: Information sources- YouTube videos on SEQTA and internet 1\. Phineas Gage Observation- (1848) p 16-17 2\. Henry Molaison Psychosurgery case study- 60 years of study: (Patient M) (1953), neurosurgeon William Beecher Scoville performed a bilateral mesial temporal lobe resection on patient Henry Molaison, who suffered from epilepsy. The operation was novel as a treatment for epilepsy and had an unexpected consequence: a severe compromise of Molaison\'s anterograde memory. 3\. Jill Bolte- Taylor- Her stroke of insight (1996) 4\. Roger Sperry Neuroscientist 1968- Split brains experiments and research p17 -- Nobel prize 1981 for breakthrough discovery on functional specialisation of the hemispheres. Cutting the corpus callosum to decrease severe epileptic seizures. Each hemisphere has its own separate perception, concepts, and impulses to act. Perceptual disabilities. Conscious right hemisphere unable to express its feelings desires or thinking due to lack of language. **Split brain explanation:** In these early studies, stimuli, for instance objects, that were presented to the left hemisphere either physically in the right hand or as an image in the right visual half-field, could be readily named (as the left hemisphere is dominant for language) or pointed out with the right hand (which is controlled by the left hemisphere). The patient's behavior became intriguing when the stimuli were presented in the left visual field or in the left hand. Now the patient, or at least the verbal left hemisphere, appeared oblivious to the fact that there had been a stimulus at all but was nevertheless able to select the correct object from an array of alternatives presented to the left hand or the left visual half-field (see Fig. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7305066/figure/Fig1/)). In a particularly dramatic recorded demonstration, the famous patient "Joe" was able to draw a cowboy hat with his left hand in response to the word "Texas" presented in his left visual half field. His commentary (produced by the verbal left hemisphere) showed a complete absence of insight into why his left hand had drawn this cowboy hat. Another astonishing example involved the same patient. MacKay and MacKay ((https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7305066/#CR66)) flashed a digit in the left visual field and trained the patient to play a version of '20 questions' across hemispheres. The left hemisphere guessed the answer vocally, and the right hemisphere provided responses by pointing 'up' (meaning 'guess a higher number') or 'down' with the left hand. In this way the patient managed to vocalize the right answer. This suggests two independent conscious agents communicating with each other (one steering the left hand, the other agent controlling vocal expressions). However, note that an alternative interpretation is possible. Perhaps the patient knows the answer but finds it hard to vocalise. The '20 questions' then simply help him in finding the correct vocalisation.