Brain II: Methods of Research

Here are four methods, selected from the eight methods discussed in the lecture video.

Lesion or patient behavioral studies. After someone has surgery to remove part of the patients brain there may be a lesion in a particular location. Lesions may also occur after head injury or other trauma, such as a stroke. Lesions prevent function in a particular brain region. Psychologists can study the differences in behavior and cognition between people with lesions and normal people. By analyzing these differences psychologists can infer that the part of the brain with the lesion is involved in a particular behavior or cognitive process.

Electroencephalography (EEG) measures the electrical activity on the scalp of a person. This electrical activity is produced by the activity of neurons. This allows researchers to observe rapid changes in electrical activity that is associated with a particular cognitive process.

Functional magnetic resonance imaging (fMRI) uses a large magnetic field to measure differences in blood flow across the brain. Changes in blood flow are believed to be associated with changes in neural activity. Scientists can study the changes in blood flow that are associated with particular cognitive processes.

Transcranial magnetic stimulation (TMS) deliver magnetic pulses to the brain to deactivate a particular brain region. By deactivating a particular brain region scientists can study the effects of loss of activity in that region on particular cognitive processes.

Example study using one of these methods: Phineas Gage had an iron rod go through his skull and into his orbitofrontal cortex. Afterwards he retained his intelligence, but his behavior was dramatically different. He became, irritable, rude, irresponsible and dishonest. Scientists could conclude that this area of the brain is necessary for appropriate social behavior, emotion, and morality. This is an example of a lesion-based study. Anther example is studies of split brain patients.