Chapter Three: The Biological Bases of Behavior

C. Looking Inside the Brain: Research Methods

Mapping brain functions and structures require specialized techniques.

1. Electrical Recordings
2. Lesioning
3. Electrical Stimulation of the Brain
4. Brain-Imaging Procedures

Contents

Electrical Recordings

The electrical activity of the brain can be recorded.

• The electroencephalograph EEG is science's brain tape recorder.
  
  
• Figure 3.12 demonstrates how the EEG electrode sums and amplifies the action potentials of "billions and billions" of cells in action.
  
  
• (not active at this time) to chapter 5 to see how the EEG is used in sleep research.

Lesioning - Don't try this at home!

Damage to specific parts of the brain often produces changes in behavior.

• Natural events like tumors, strokes, and injuries produce lesions.

• Laboratory events create more controlled damage:
  • Lesioning
  • Stereotaxic instrument (not to be confused with the latest surround-sound walkmen).

Electrical Stimulation of the Brain

Sending a weak electric current into a brain structure stimulates (activate) it into action.

Brain-Imaging Procedures

CT (Computerized Tomography) scan:

• A computer-enhanced X-ray of brain structures.
• Example of CT (figure 3.14)

PET (Positron Emission Tomography) scan:

• Maps brain activity by monitoring metabolic activity (burning radioactively tagged sugar)
• Example of PET (figure 3.15)
• PET also used to study neurotransmitters.

MRI (Magnetic Resonance Imaging) scan:

• Produces 3-dimensional images of the brain structures.
• Example of MRI (figure 3.16)

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