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