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Biopsychology - Coggle Diagram

- - - - Overall, the left hemisphere of the brain is associated with language production and comprehension.
        
        Therefore, language is an example of a cognitive ability which is both localised and lateralised #
  - - - Using PET scans, semantic memories were recalled from left prefrontal cortex, whilst episodic memories were recalled from right prefrontal cortex.
        
        Shows that different areas of brain are responsible for different functions, as predicted by localisation theory.
        
        Idea was further supported by Petersen et al (1988), who found Wernicke’s area activation is required for listening tasks, whereas Broca’s area is required for reading tasks.
        
        Confirms the idea that Wernicke’s area is involved in speech comprehension, whilst Wernicke’s area is responsible for language production.
    - - was injured by a blasting rod which intersected the left side of his face, tearing through his prefrontal cortex. “The damage involved both left and right 2 prefrontal cortices in a pattern that, as confirmed by Gage’s modern counterparts, causes a defect in rational decision making and the processing of emotion”. Such case studies, particularly those showing marked differences after trauma, demonstrate the idea that some areas of the brain are responsible for specific functions. However, with the use of case studies, the subjectivity of the conclusions drawn and the unusual sample, alongside a lack of control over confounding and extraneous variables, must also be considered.
    - - The opposite to localisation theory would be a holistic view of brain function, suggesting that each function requires several brain areas to be activated and that these functions are not restricted to these areas. For example, after removing 20-50% of the cortices belonging to rats, found that no specific brain area or lesion was associated with learning how to traverse through a maze. This suggests that intelligence, or even learning, is too complex and advanced a cognitive ability to be restricted to certain areas of the brain. Therefore, this suggests that localisation theory may provide a better explanation for ‘simple’, rather than complex, brain functions.
    - - Dougherty et al (2002)
        
        studied 44 OCD sufferers who’d undergone lesioning of the cingulate gyrus (cingulotomy) in order to control their symptoms. After being assessed using the Structured Clinical Interview for DSMIII-R, the researchers found that “At mean follow-up of 32 months after one or more cingulotomies, 3 32% met criteria for treatment response, and 14% were partial responders. 32-45% of patients previously unresponsive to medication and behavioural treatments for OCD were at least partly improved after cingulotomy”. This suggests that not only are certain brain areas responsible for symptoms of OCD, but that an improved understanding of localisation of brain function has practical applications in the development of more advanced treatments for serious mental disorders.
- - - - Case Studies
        
        — Individual differences in circadian rhythms = Circadian rhythms may not and do not always have to conform to cyclical 24 hour periods. For example, Dr. Espie, a Professor of sleep medicine at Oxford University, delayed the starting time of Monkseaton High School to 10 AM, instead of the usual 8AM. The researchers noted that “GCSE results went up from 34% of pupils scoring 5 A-C grades 13 including English and Maths, to 53%. For disadvantaged students, the rates of scoring 5 A-C grades increased from 12% to 42%”. Therefore, this is a real-life example of how the circadian rhythms of teenagers specifically are not always in line with that of adults, and so an appreciate of this can improve educational attainment.
        
        — The confounding effect of artificial light = As demonstrated by Czeisler et al (1999), artificial lighting can create shifts in circadian rhythms by up to 6 hours. Siffre’s research was conducted at a time where researchers believed that artificial lighting had no effect on biological rhythms. The use of artificial light meant that over 2 months, Siffre could have entrained his own circadian rhythm through signaling sleeping and waking times by using the light, meaning that the conclusions made about his ‘free-running’ circadian rhythm may not be entirely accurate.
        
        — Detrimental impacts on health in shift workers = Karlsson, Knutsson and Lindahl (2001) found 14 that shift work was associated with obesity, high triglycerides and low concentrations of HDL cholesterol, which the researchers suggest may demonstrate a link between the desynchronisation of circadian sleep-wake cycles in shift workers and the consequent disruptions in the biological control of metabolism (and therefore core body temperature). This suggests that there may be practical uses in an improved understanding of the effects of desynchronisation. This in turn has economical implications, in terms of companies who employ shift-workers making the effort to revise their policies in order to reduce days taken off sick.
        
        — Use of case studies and small samples in isolation investigations = Although Siffre conducted multiple isolation studies, his results may not be able to be generalised to the wider population, especially as individual differences in the duration and stages of circadian rhythms has been shown (i.e. Monkseaton High School), hence his results may lack ecological validity. For example, even Siffre himself noted that as he grew older, his endogenous pacemaker ticked at a slower rate, which may have acted as an uncontrolled confounding variable in his investigations. The same can be said for other isolation studies, such as Aschoff and Wever, where large numbers of participants are unlikely to want to participate. This again limits the extent to which the findings represent the experiences of the general population.
  - - - Case Studies
        
        — Menstrual synchronisation is not always present in all-female samples = For example, Trevathan et al (1993) noted that he had found no evidence of menstrual synchronisation in the all-female participants used, which suggests that there are external (extraneous) variables which may affect the timing and duration of their menstrual cycles. McClintock et al. did not control for such extraneous factors e.g. smoking, physical activity and alcohol consumption. Therefore, this raises doubts about the strength of the influence of pheromones, as an exogenous zeitgeber which can entrain infradian rhythms.
        
        — Dispute over the chemical and hormonal basis of SAD = Gloth et al (1999) found that, when treating sufferers of SAD with either Vitamin D supplements or broad-spectrum phototherapy, “all subjects receiving vitamin D improved in all outcome measures. The phototherapy group showed no significant change in depression scale measures”. Patients who’d been given vitamin D supplements also experienced a 74% improvement in their depression measures. Therefore, this suggests that phototherapy is ineffective in treating SAD. Since phototherapy involves exposure to bright light in order to increase the rate at which the pineal gland secretes melatonin, this implies that melatonin and serotonin levels have little parts to play in the development of SAD and in the entrainment of circadian sleep-wake cycles.
        
        +Animal studies supporting the role of pheromones = The link between the pheromone release and animal behaviour has been extensively supported. For example, Luo et al (2003) studied the effects of pheromonal signals in the olfactory bulb of mice and concluded that “mammals encode social and 16 reproductive information by integrating vomeronasal sensory activity specific to sex and genetic makeup”. Therefore, this suggests that endogenous pacemakers have a critical role in the entraining of biological rhythms in animals, whose findings can then be generalised to humans.
- - - - +Neuroplasticity occurs in animals too = Hubel and Weisel (1970) sutured the right eye of kittens, who are blind from birth, for a period of 6 months, opening the eyes and several points and monitoring brain activity in the visual cortex. The researchers found that, although the right eye was closed, there was still activity in the left visual cortex, corresponding to the development of occular dominance columns. This was demonstrated by how “during the period of high susceptibility in the 7 fourth and fifth weeks eye closure for as little as 3-4 days leads to a sharp decline in the number of cells that can be driven from both eyes”. This therefore supports the idea that areas of the brain receiving no input can take over the function of highly stimulated areas, despite originally having different functions.
      - +Cognitive reserve may increase the rate of functional recovery = Cognitive reserve is the level of education a person has attained and how long they have been in education. Research suggests that an increased cognitive reserve increases the likelihood of making a disability-free recovery (DFR) after trauma, due to increased rates of neuroplasticity. For example, Schneider et al (2014) found that of the 769 patients studied, 214 achieved DFR after 1 year. Of those, 50.7% had between 12 8 and 15 years of previous education and 25.2% had more than 16 years. This suggests that individuals who have been in education for a longer time may have developed the ability to form neuronal connections at a high rate, and therefore experience high levels of functional recovery, demonstrating positive plasticity.
      - +Evidence supporting the positive and negative effects of neuroplasticity = Much research has been carried out into the phenomenon of plasticity. For example, Ramachandran et al. has demonstrated negative plasticity through providing an explanation for phantom limb syndrome in terms of cortical reorganization in the cortex and thalamus (particularly, the somatosensory area). Positive plasticity has been demonstrated by the case study of Jodi Miller, who has shown the power of recruiting homologous areas on the opposite side of the brain, axonal sprouting and the reformation of blood vessels. Therefore, there is evidence supporting not only the existence of, but also the uses of plasticity.
      - — There are limits to spontaneous and functional recovery = Although after trauma the brain activates secondary neural circuits which contribute towards reinstating normal function (law of equipotentiality), the brain can only ‘repair’ itself up to a specific point, after which motor therapy or electrical stimulation is needed to increase recovery rates. For example, Lieperta et al (1998) found that after constraint-induced movement therapy, the motor performance of stroke patients improved significantly. Therefore, this suggests that functional recovery cannot be relied upon to reinstate normal function.