biological approach: the relationship between the brain and behaviour Flashcards
MRI (what is it)
- An MRI scanner uses a magnetic field and radio waves to map the activity of hydrogen molecules.
- Hydrogen molecules are present in different brain tissue to different degrees.
- A static image is created through a compilation of many snapshots of the brain.
- The image can either be viewed as a two-dimensional slice of the brain from any angle or it can be used to create a three-dimensional images of brain structures.
- The images show the structure of the brain however don’t give any indication of brain function.
MRI (s&w)
S- It enables researchers to pinpoint specific brain structures which may be damaged or have increased grey matter to identify the link between brain and behaviour
W- MRI scanners are prone to disturbance caused by noise, temperature and human error in calibration, which means that they are not always reliable
fMRI (what is it)
Measures oxygenated blood flow in the brain i.e. brain activity
fMRI (s&w)
S- It enables researchers to measure oxygenated blood in specific brain regions which can inform them of brain activity linked to cognitive processes such as emotion
W- fMRI is slow, having a 5-second delay between brain activity and measurement and so it may miss some important information. Low temporal resolution
study: Maguire (2000) AIM
aimed to investigate neuroplasticity and localisation of function in the brain.
study: Maguire (2000) METHOD
Maguire looked at MRI scans of right-handed male taxi drivers who had passed ‘The Knowledge’, a test of spatial navigation and who had been driving for at least 18 months.
She compared these to pre-existing MRI scans of 50 healthy, right-handed males who were not taxi drivers, they served as a control group.
study: Maguire (2000) RESULTS
Maguire found that the posterior hippocampus of the taxi drivers showed a greater volume of grey matter than that of the non taxi drivers, who had increased grey matter in their anterior hippocampus compared to the taxi drivers.
study: Maguire (2000) CONCLUSION + LINK
This supported the theory of localisation of function as only certain areas of the brain were affected by being a taxi driver.
She used voxel-based morphometry (VBM) which focuses on the density of grey matter from MRI scans to find a positive correlation between volume of posterior hippocampal grey matter and length of time spent as a taxi driver.
This supported the theory of neuroplasticity as the brain changed as a response to an external stimuli.
Overall, Maguire’s study shows how brain imaging techniques such as the MRI can be used to study the brain and behaviour.
study: Maguire (2000) STRENGTH
- Highly controlled clinical method of obtaining objective data, this could then be easily compared and analysed
- Understanding neuroplasticity can help aid the recovery of people who have suffered brain damage
study: Maguire (2000) WEAKNESS
- A correlation can’t show cause-and-effect so it is impossible to know whether the taxi drivers already had naturally high levels of hippocampal grey matter
- Results are only generalisable to male, right-handed London taxi drivers, so the nature of neuroplasticity in women is not known
study: Fisher et al (2005) AIM
to investigate the brain systems involved in early-stage intense romantic love
study: Fisher et al (2005) METHOD
- 10 females, 7 males from NY state university (self-selecting sample), mean age 20, all participants reported being ‘in love’ for a mean range of 7 months
- Participants placed in an fMRI scanner and shown a photograph of their loved one, followed by a distraction task, then a ‘neutral’ photograph of an acquaintance with whom they had a non-emotional relationship
study: Fisher et al (2005) RESULTS
- when the participants viewed the photograph of their loved one, specific areas of their brain were active: the right ventral tegmental areas and the right caudate nucleus. - Both these areas are strongly associated with dopamine activation (a neurotransmitter which induces a feeling of reward and motivation in people)
study: Fisher et al (2005) CONCLUSION
- results suggest that people in the early, intense stages of romantic love access the areas of the brain most associated with motivation and reward, giving rise to the idea that people may become ‘addicted to love’
- Dopaminergic reward pathways may contribute to the ‘general arousal’ component of romantic love, making it a biological process rather than a cognitive one
study: Fisher et al (2005) STRENGTHS
- Standardised procedure → study is replicable, increases its reliability
- Use of fMRI means that the study was able to support to the idea that human beings may have evolved a brain system which ensures that they become addicted to love, increasing the validity of the study
study: Fisher et al (2005) WEAKNESSES
- Small sample size of 17 participants means that the results are not very meaningful, may not be robust in terms of statistical analysis
- Idea that romantic love can be measured via fMRI is overly reductionist → may be a range of other factors involved e.g. compatible personalities, shared ideals, cultural influences
localisation
the idea that different regions of the brain are responsible for different functions or behaviours
the brain
- the most complex part of the body
- responsible for higher level mental functions such as thinking, sensation and behaviour
right hemisphere
- responsible for emotion, creativity and belief
- controls the left side of the body.
left hemisphere
- responsible for logic, language and problem solving
- controls the right side of the body
cerebral cortex
- outer structure of the brain
- split up into 4 lobes: frontal, parietal, occipital, temporal
occipital lobe
vision
parietal lobe
higher senses and language functions
frontal lobe
movement, cognition, decision making and reasoning
temporal lobe
hearing memory and meaning
Broca’s area
- found in the left frontal lobe
- responsible for language production
Wernicke’s area
- found in the left temporal lobe
- responsible for language comprehension
limbic system
- controls the basic emotions (fear, pleasure, hunger) and drives (hunger, sex)
- amygdala, thalamus, hypothalamus, hippocampus
thalamus
sensation
hippocampus
involved in memory and learning
hypothalamus
- regulates bodily functions
- controls the pituitary gland
amygdala
anger, fear, emotion
cerebellum
coordinates and regulates muscular activity and balance
brain stem
- connects brain to spinal cord
- involved in regulating automatic functions e.g. breathing, temperature
study: Broca’s case study of Tan AIM
- to investigate the localisation of language production to a specific area of the brain
- he did this to find an explanation for Tan’s unusual circumstance of being unable to produce speech
study: Broca’s case study of Tan METHOD
- Broca observed Tan over the course of a number of years and after Tan’s death
- he conducted an autopsy on Tan’s brain.
study: Broca’s case study of Tan RESULTS
- this revealed a lesion in an area in the left frontal lobe, providing Broca with evidence that language production is localised to this area, now called Broca’s Area
study: Broca’s case study of Tan CONCLUSION
- language production can be localised to the left frontal lobe in ‘Broca’s area’
- If damage occurs in this area, it results in Broca’s aphasia (inability to produce coherent speech)
- Therefore, this supports the localisation of function as language production has been localised to a specific area of the brain- Broca’s area.
study: Broca’s case study of Tan LINK/SUMMARY
- Localisation of function has therefore been proven by Broca
- His study showed that a specific part of the brain, Broca’s area, was responsible for a specific function, language production.
- Localisation of function was also shown as when this specific region was damaged, the specific function that area performs was inhibited.
- In this case, when Broca;s area was damaged, language production was inhibited
study: Broca’s case study of Tan STRENGTHS
- Longitudinal nature → full, in-depth investigation into the individual and their condition was possible
- Tan’s case highlighted important new insight into the brain and its link to language and speech production
study: Broca’s case study of Tan WEAKNESSES
- Very dated research, a modern researcher could use a range of brain-imaging techniques to isolate the brain region involved in the condition
- May have been other explanations for Tan’s speech impairment which were not explored at the time
study: Maguire (2000) AIM
to investigate localisation of function linked to spatial navigation experience in London black cab taxi drivers