What is the main idea of the activation-synthesis hypothesis?
Neurons in the pons fire spontaneously during REM sleep, sending random signals to various areas in the cortex and the emtional areas in the limbic system. The signals are random, but the brain tries to make sense of them and produce a meaningful interpretation. Thus, a dream is the brain's synthesis of these signals. Because the signals evoke random memories and visual images, the brain has a difficult time weaving a coherent story.