Chapter 4

3. What changes in brain activity occur as a person goes to sleep, and how do we measure these changes?
As a person drifts off to sleep they go through 4 stages from being in a light sleep in stage 1, to a deep sleep in stage 4. The brain activity slows from stage 1 to stage 4. These changes can be measured by an EEG (electroencephalogram).

5. What is addiction, and what brain processes play a central role in it?
Addiction is when the body has to have a certain substance to stay normal and not go through withdrawal.
The insula becomes active when viewing images of the drugs the person is addicted to and is the main cause of addiction.