IB Psychology Notes

Biological Approach to Behavior

The brain and behavior:

Explain one technique used to study the brain in relation to behavior.

One technique used to study the brain is Functional magnetic resonance imaging or fMRI. fMRI measures changes in blood flow that occur with brain activity.

Measures blood flow, not neural activity. Able to show the ongoing brain process.

Used to map cognitive functions in different brain regions as well as brain functions at the level of neural processes.

Serotonin is a neurotransmitter that helps to form neural networks.

A. To investigate the relationship between neurotransmission, serotonin levels, and violent behavior.

S. Healthy volunteers, nineteen participants, nine women and ten men, average age of twenty-five.

M. Healthy participants' serotonin levels were manipulated by altering their diet using tryptophan, an amino acid that builds serotonin levels. Placebo with normal levels of tryptophan and drink that lacked tryptophan. Took place in two weeks, one session each week. fMRI scans are used to measure brain activity when serotonin is manipulated and they are exposed to emotional faces as well, happy, sad, etc., and participants then self-reported mood.

Reduced activity in the frontal lobe during low serotonin conditions when participants viewed an angry face. Reduced activation of the prefrontal cortex may affect violence and react impulsively.

Strengths and limitations:

It doesn't use radiation like X-rays, PET scans, and CT scans.

The images fMRI produces is a very high spatial resolution.

Therefore provides a clear picture on how the brain is localized.

It is expensive compared to other techniques and can only capture a clear image if the person stands still.

Random noise during scan can cause motion and therefore muddle the results, so a lot of trials are required.

Poor temporal resolution because of a five second lag between initial neural activity and image.

Therefore, does not truly represent moment to moment brain activity.