It is obviously more than just visual. As you described, imagination and spasms.
What are these derived from?
That does not directly answer the question, does it? Activated by........Conscious or subconscious?[/b]
Brain-imaging reports generally support Solms' theory that dreams derive from a frontal-brain motivation system, Braun notes (SN: 1/17/98, p. 44). However, a frontal-brain area considered pivotal for self-monitoring and abstract thought naps throughout sleep. Braun considers this finding to clash with the Freudian notion of dreams as hotbeds of disguised meaning.[/b]
http://www.sciencenews.org/articles/20010811/bob12.asp see the main bulk of evidence is for the dreams coming from your visual primitive areas not from fraudien belife like subconsious which has no proof. you can go with the evidenece or your own belife.