A2 biopsychology Flashcards

Question

How can slit brain patients tell us about lateralisation?

Answer 1

Some people had had accidents that affect a certain part of the brain. Some people can speak clearly and not understand a question and some the other way.

Answer 2

aim: investigate hemispheric lateralisation of function in split brain patients. Stimulus shown to either LHS or RHS and accuracy in reporting is recorded. findings: stimuli presented to RHS can be reported verbally but not signed with right hand. Stimuli presented to LHS is the opposite. conclusion: severing corpus callosum prevents lateralised functional areas from receiving signals from other side. Language is lateralised to left hemisphere.

Answer 3

P - It is assumed that the main advantage of brain lateralisation is that it increases neural processing capacity (the ability to perform multiple tasks simultaneously). E - Rogers et al. (2004) found that in a domestic chicken, brain lateralisation is associated with an enhanced ability to perform two tasks simultaneously (finding food and being vigilant for predators). E - Using only one hemisphere to engage in a task leaves the other hemisphere free to engage in other functions. L - This provides evidence for the advantages of brain lateralisation and demonstrates how it can enhance brain efficiency in cognitive tasks. However this experiment was done on animals so cannot be generalised to humans P - much of the research into lateralisation is flawed because the split-brain procedure is rarely carried out now, meaning patients are difficult to come by. E - such studies often include very few participants, and sperry and Gazzinga’s research only included 11 patients, all of which had varying degrees of epilepsy E - consequently, some psychologists have argued that Sperry’s research is really a collection of case studies that take an idiographic approach. Although an idiographic approach provides rich and interesting info in relation to individual cases, we are unable to create general laws or apply the results, as found in nomothetic research L - any conclusions drawn are representative only of those individuals who had a confounding physical disorder that made the procedure necessary. This is problematic as such results cannot be generalised to the wider population. P - Finally, it could be argued that language may not be restricted to the left hemisphere. E - Turk et al. (2002) discovered a patient who suffered damage to the left hemisphere but developed the capacity to speak in the right hemisphere, eventually leading to the ability to speak about the information presented to either side of the brain. E - This suggests that perhaps lateralisation is not fixed and that the brain can adapt following damage to certain areas. L - May be reductionist or the sample may have extraneous variables

Answer 4

There is further research to support the notion of brain plasticity. Maguire et al. found that the posterior hippocampal volume of London taxi drivers’ brains was positively correlated with their time as a taxi driver and that there were significant differences between the taxi drivers’ brains and those of controls. This shows that the brain can permanently change in response to frequent exposure to a particular task. There is research to support the claim for functional recovery. Taijiri et al. (2013) found that stem cells provided to rats after brain trauma showed a clear development of neuron-like cells in the area of injury. This demonstrates the ability of the brain to create new connections using neurons manufactured by stem cells. While there is evidence for functional recovery, it is possible that this ability can deteriorate with age. Elbert et al. concluded that the capacity for neural reorganisation is much greater in children than in adults, meaning that neural regeneration is less effective in older brains. This may explain why adults find change more demanding than do young people. Therefore, we must consider individual differences when assessing the likelihood of functional recovery in the brain after trauma. A final strength of research examining plasticity and functional recovery is the application of the findings to the field of neurorehabilitation. Understanding the processes of plasticity and functional recovery led to the development of neurorehabilitation which uses motor therapy and electrical stimulation of the brain to counter the negative effects and deficits in motor and cognitive functions following accidents, injuries and/or strokes. This demonstrates the positive application of research in this area to help improve the cognitive functions of people suffering from injuries.

Answer 5

P - an advantage of the EEG, in comparison to fMRI, is that it has good temporal resolution. E - Temporal resolution refers to the accuracy of the scanner in relation to time: or how quickly the scanner can detect changes in brain activity. EEG scanners take readings every millisecond, meaning it can record the brain's activity in real time as opposed to looking at a passive brain. E - however fMRI scans have a temporal resolution of 1-4 seconds which is worse than other techniques (e.g. EEG) L - this suggest that EEG can provide a high degree of accuracy when examining the onset of brain activity, allowing psychologist to make accurate conclusions in relation to the timing of neural activity, in comparison to fMRI. P - However, one strength of fMRI in comparison to EEG, is that it has good spatial resolution. E - spatial resolution refers to the smallest feature that a scanner can detect, and is an important feature of brain scanning. Greater spatial resolution allows psychologists to discriminate between different brain regions with greater accuracy. fMRI scans have a spatial resolution of approximately 1-2mm which is significantly better than other techniques. E - EEG, on the other hand, can only detect activity in superficial regions of the brain L - therefore, psychologists can determine the activity of different brain regions with greater accuracy with fMRI, in comparison to EEG, which makes fMRI an ideal choice when trying to pinpoint specific brain regions. P - Finally one issue of both fMRI and EEG is the inability to show causation E - fMRI scans do not provide a direct measure of neural activity. fMRI scans simply measure changes in blood flow and therefore it is impossible to infer causation (at a neural level) E - likewise, the issue with EEG is that electrical activity is often detected in several regions of the brain simultaneously. L - consequently, psychologists are unable to conclude whether particular brain regions are associated with specific functions (fMRI) and which area/region the electrical activity took place (EEG) making solid cause and effect conclusions impossible

A2 biopsychology Flashcards

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