Chapter 8: Why sleep? Why REM? Why Dreams?

Question 1

activation-synthesis

hypothesis 288

Answer 1

this theory emphasizes that dreams begin with arousing stimuli that are generated within the brain combined with recent memories and any information the brain is receiving from the senses.

Question 2

clinico-anatomical

hypothesis 288

Answer 2

Puts less emphasis on the pons, PGO waves, or REM sleep.
It regards dreams as thinking that takes place under unusual conditions. One of those conditions is that the brain is getting little information from the sense organs, and the primary visual and auditory areas of the cortex have lower than usual activity, so other brain areas are free to generate images without constraints or interference. Also, the primary motor cortex is
suppressed, as are the motor neurons of the spinal cord, so arousal cannot lead to action. Activity is suppressed in the prefrontal cortex, which is important for working memory (memory of very recent events). Consequently, we not only forget most dreams after we awaken, but we also lose track of what has been happening within a dream, and sudden scene changes are common. We also lose a sense of volition—that
is, planning. It seems that events just happen, without any intention on our part.