Structural and functional differences in brain mechanisms of dream recall

Once questioned the assumption that dreaming depends on REM sleep, subsequent studies focused on the neural correlates of dream recall (DR). Considering the indirect access to the sleep mentation, this chapter reviews the main neuropsychological, neuroimaging, and electrophysiological findings on DR. Compelling evidence supports the idea that shared mechanisms between sleep and wakefulness underline the encoding and retrieval of episodic memory, studying DR as amnestic trace. On the other side, several observations suggest that higher cortical activation is crucial to dreaming. Interestingly, individual stable characteristics (trait-like/structural differences) and the neural functioning in a specific physiological state (state-like/functional differences) could affect dream features. Moreover, we outline that also the brain maturation across the life span could explain some differences in dream experience. Although great advances have been made in dream research, the whole knowledge is heterogeneous, and a unifying theory about dream recall-related mechanisms is still lacking.