Brain correlates of successful dream recall

The scientific study of dreaming grew up rapidly in the 1950s, after the discovery of rapid eye movement (REM) sleep, which was considered to be a neurophysiologic marker of dreaming. Subsequent and more accurate investigations, however, showed that qualitatively different mental experiences are developed during all sleep stages. The recent progress with electrophysiologic (high-density electroencephalogram [EEG]) and imaging techniques seems promising to elucidate the functioning of the brain structures presumably involved in the elaboration of dreaming, both in healthy subjects and in patients with acute or chronic brain damage, neurodegenerative diseases, or sleep disorders. This chapter summarizes the established findings and emerging knowledge on the neural correlates of successful dream recall. Lines of recent evidence converge in indicating that dream recall is related to specific electroencephalographic frequencies and to peculiar topographic features on the scalp EEG. These results are consistent with neuropsychological data, pointing to an overlap between functional and structural cerebral substrates of waking and REM sleep mental imagery.