biopsychology Flashcards
what is the process of synaptic transmission?
- nerve impulse travels down the axon
- then reaches synaptic terminal at presynaptic membrane and triggers release of neurotransmitters
- fired into the synaptic gap
- the neurotransmitters bind with receptors on the dendrite of the post synaptic neuron
- post synaptic receptors are activated by the neurotransmitter and either increase or decrease likelihood that the post synaptic neuron will fire an action potential
- eventually neurotransmitter molecules are cleared from synaptic gap via reuptake or via enzymes breaking down the transmitter
what are the strengths of localisation of function?
- case study evidence
- Phineas Gage supports localisatiob as only frontal lobe was damaged which affected his personality
- all other aspects functioned normally which showed the part of the brain that controls personality is localised in the frontal lobe
- use of brain scans
- can be used to demonstrate how Wernicke and Broca’s area are different
- showed how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task, suggesting that these areas of the brain have different functions
- supports how brain scans are highly objective and a scientific method of measuring activity in the brain as they produce high resolution images that provide a clear picture on how the brain is localised
what are the weaknesses of localisation of function?
- however, case studies lack generalisability
- they are unique cases and can’t be applied to everyone’s brain
- in theory, there are other factors that may have contributed towards Gage’s changes in personality
- one case is not enough to make nomothetic conclusions on localisation
- neural plasticity
- the ability the brain has to remap and recover lost function when damaged
- other parts can adapt and grow new pathways and replace new functions
- EB?
what are the strengths of lateralisation?
- Sperry’s split-brain research - supporting evidence
- procedure was the same and standardised for the 11 participants with controls in place
- these features of the lab experiment suggests research into lateralisation has high internal validity, showing the results were due to split-brain
- more recent studies to strengthen the concept through more split-brain research
- patients were faster at identifying the odd one out in an array of similar objects than normal controls
- in a normal brain, the left’s side better cognitive strategies counteract the right side’s
- supports the idea of lateralisation that the left and right side are distinct
what are the weaknesses of lateralisation?
- however, it was a lab experiment and doesn’t reflect ordinary visuospatial tasks done in real life as normally participants would be able to adjust visual position
- despite this, Sperry’s methods has led to valuable knowledge coming through isolating the hemispheres to understand lateralisation
- case studies like EB have challenged the claim that brain functions are lateralised
- EB suffered immediate loss of language abilities after having the left hemisphere removed but with intensive rehab, his language fluency improved remarkably over the next 2-3 years
- case study supports the idea that lateralisation may depend on age
- research has shown language becomes more lateralised with age but after 25, it decreases with each decade of life
- this suggests functions might be dealt with both hemispheres as we get older to compensate for age related declines in function
what are the strengths of split-brain research?
- control variables
- increases internal validity
what are the weaknesses of split-brain research?
- sample size
- only 11 makes it hard to generalise to wider population
- but only ethical way as not many split brain patients available at the time
- confounding variables
- compared to a neurotypical control group without epilepsy
- their abilities could be explained by their epilepsy rather than split brain making it a confounding variable as the epilepsy varies systematically with the IV of split brain
- a sample of non-split brain patients with epilepsy would’ve been better
what are the strengths and weaknesses of ways of studying the brain?
fmri - non invasive, no surgery or risk, high spatial resolution, shows exactly where activity is happening in the brain, expensive, can only measure blood flow and not activity of neurons, poor temporal resolution - around 5 second time delay between image on screen and firing of neurons
EEG - high temporal resolution - shows exactly when the activity happens at one milisecond, contributed to understanding of stages of sleep and diagnosis of disorders like epilepsy, can only detect activity in regions of the brain closer to the surface so can’t with deeper areas like the hippocampus
ERP - good temporal resolution - led to use in measurement of specific cognitive functions, requires a large number of trials to get meaningful data and difficult to eliminate baclground noises and extraneous ,materials to get pure data
post-mortem - allows deeper areas of the brain to be studied and to be compared with neurotypical brains, retrospective approach - can’t conduct follow up studies, ethical issues
what are the strengths of circadian rhythms?
- real life application
- understanding rhythms like the sleep wake cycle has allowed researchers to understand what happens when they are disrupted
- research as shown that shift workers suffer a concentration lapse at 6am, increasing likelihood of accidents
- and more likely to suffer from heart disease from stress of adjusting
- helps to ensure the safety of workers and allowed guidelines to be put into place of how best to deal with shift work
- therefore, useful in society
what are the weaknesses of circadian rhythms?
- issue with case study evidence
- one problem with studies on the sleep wake cycle is that they tend to involve small groups of ppts
- studies like Asch and Weaver were conducted on only few ppts and Siffre noticed age can affect findings - when he went at age 60 his body responded differently and adjusted to a 48 hour cycle
- this suggests factors such as age and individual factors may have significant impact on our circadian rhythms and ability to generalise and so lacks external validity
- poor control in studies
- assumed that only natural light that had on influence on our biological rhythms however another study found that artifical light could adjust the sleep wake cycle too
suggests artifical light could be a confounding variable in studies such as Siffre’s
what are the strengths of plasticity and functional recovery?
- real world application
- understanding of features of functional recovery has been important in the field of neurohabilitation
- specifially axonal growth has allowed for new therapies to be tried
- useful in society and treatment
- life long ability
- in general plasticity reduces with age
- golf study with ppts between 40-60 showed novice golfers were better than the control group with increased motor cortex activity, showing plasticity can continue throughout life
what are the weaknesses of plasticity and functional recovery?
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