Unit 2: Biological Level of Analysis Session 10
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Transcript of Unit 2: Biological Level of Analysis Session 10
Unit 2:Biological Level of
AnalysisSession 10
‘All that is psychological is first physiological’
Today’s learning outcome
Discuss the use of brain imaging technologies in investigating the relationship between biological factors and behaviour.
Don’t forget to take notes- this session will help you to complete some of your holiday assignment!
Modern technology is now extensively used in neuropsychology
Allows researchers to:◦ Study the active brain◦ See where specific brain processes take place◦ Enables localisation of function in LIVING brain
The use of technology in brain research
Animals are still extensively used in brain research as they allow psychologists to study specific biological correlates of behaviour using invasive techniques*
Many early experiments involve invasive techniques
*often involves removing (ablation) or scarring (lesioning) brain tissue in order to
study behavioural changes i.e. Study behaviour before and after
ablation/lesioning
Invasive techniques in brain research
Classic study involving invasive technique Lesioned part of brain called ventromedial
hypothalamus in rats Rats increased food intake dramatically, and often
doubled in weight Led researchers to believe that hypothalamus acted as
a brake on eating
More recent research, however, has argued that although hypothalamus plays a role in regulation of hunger, its exact role is not yet understood.
Hetherington and Ranson (1942)
So what’s the problem???
The use of invasive techniques?
CanDoCan’tDo With Participants
Got it in the bag yet?
Invasive techniques raise serious ethical concerns
In cases of lesioning and ablation, the potential harm to the animal cannot be determined
In addition, any damage caused cannot be reversed
Finally there is the question of causing pain to animals
Ethical issues with invasive techniques
Modern researchers use brain imaging techniques to investigate relationship between behaviour and brain structures
1. Electroencephalogram (EEG)2. Positron Emission Topography (PET)3. Magnetic Resonance Imaging (MRI)4. Functional Magnetic Resonance Imaging
(fMRI)
Modern brain imaging technologies
Image often thought of as ‘brain waves’ When neurons transport information through the
brain, they have an electrical charge Registers patterns of voltage change in the brain Psychologists have gained better understanding of
behaviours as diverse as sleep, emotions & epilepsy
Provides limited information- cannot reveal what’s happening in deeper brain regions; nor can it show actual
functioning of brain
Electroencephalogram (EEG)
Monitors glucose metabolism in brain Patient injected with harmless dose of
radioactive glucose Radioactive particles detected by PET scanner Used to diagnose abnormalities like tumors, Alzheimer’s, schizophrenia etc
Positron Emission Topography (PET)
Uses a magnetic field and radio waves to create detailed images of the body.
Gives detailed pictures of internal structures in brain
Magnetic Resonance Imaging (MRI)
Used MRI to investigate whether substance abuse (marijuana) can damage developing brain of young adults
Scan indicated that there were brain abnormalities in frontal, parietal and temporal regions in brain of marijuana users
Development of white matter (myelin*) was affected could explain slow information processing in brain
Concluded that early marijuana use can affect brain development but as study gives correlational data more research is needed
*Remember: Myelin sheath covers neuron and helps to speed up neurotransmission
Ashtari et al (2009)
Study Group Control Group
14 young men with history of heavy marijuana abuse over long period of
time
14 young men who had no history of marijuana use
Case study of H.M.
Corkin et al (1997) did MRI scan of H.M’s brain which allowed for precise picture of brain damage. Confirmed that hippocampus was missing- able to link to memory.
Where have we already seen use of MRI?
MRI scans show how blood flows in brain and can be used to identify problems with blood circulation. Can be used for early detection of Alzheimer’s
Safe to use as no radioactive material is used
Strengths of Magnetic Resonance Imaging
Scanner not a natural environment for cognition- question of ecological validity
Very expensive Movement may affect images Cannot say anything about cause and effect
relationships, only provide correlational data
Limitations of Magnetic Resonance Imaging
Watch the video
Can MRI scans catch psychopaths?
Scanner measures changes in blood flow in active brain
Blood flow associated with use of oxygen and neural activity during information processing
When participants are asked to perform a task, scientists can
observe the part of the brain that corresponds with that function
Use increased vastly over past ten years and now widely used by cognitive neuroscientists
Functional Magnetic Resonance Imaging (fMRI)
Study aimed to find biological correlates of stereotypes and prejudice
Studied brain processes as a response to extreme outgroups Scanned students’ while they were watching pictures of
different humans or objects Predicted that prefrontal cortex would be active when
students looked at humans but not objects This was found EXCEPT when students looked at pictures of
extreme outgroups e.g. Homeless and addicts Brain regions linked to disgust were then activated and
there was no activity in prefrontal cortex Concluded this indicated a dehumanisation of outgroups.
These groups apparently viewed as ‘disgusting objects’ rather than people
Harris and Fiske (2006)
Baumgartner et al (2008) Oxytocin and Trust
fMRI scans carried out on participants In oxytocin group cans showed decreases in
responses in amygdala (involved in emotional processing) and caudate nucleus (involved in learning to trust)
Explanation for behaviour in trust game
Where have we seen fMRI before?
One of most frequently used technologies in biopsychological research today
Shows actual brain activity and indicates which areas of brain are active
Scans have higher resolution than PET scans and are easier to carry out
Does not use radioactive substances Can record activity in all regions of brain
Strengths of Functional Magnetic Resonance Imaging
Watch the video
fMRI to fight depression?
Focus mostly on localised functioning in brain and does not take into account the distributed nature of processing in neural networks
Results are correlational so not possible to establish cause and effect relationships
Scanner not a natural environment for cognition- question of ecological validity
Brain areas activate for different reasons- e.g. Just because amygdala lights up does not necessarily mean fear is the response being observed
Limitations of Functional Magnetic Resonance Imaging (fMRI)
The use of PET and fMRI scans has helped psychologists to identify brain patterns for dysfunctional behaviours. There is a certain pattern for people with schizophrenia, alcoholism, depression, and other disorders
These patterns are present, even if person does not show any symptoms of disorder.
1. Do you think doctors should scan patients to let them know if they have a predisposition for a mental illness? What effect do you think this would have on the patient?
2. Could this technology be misused? Does the potential abuse of technology and knowledge mean that it should not be pursued.
Journal Entry: TOK and Ethics