Mind and consciousness during sleep

The epistemological-methodological constraints for an approach to dream as an object of scientific-experimental investigation are pointed out, along with the suggestion of a new memory paradigm, that utilizes the linguistic convention ('word play') proposed by Wittgenstein. A model of dream generation is proposed, in which mnemonic materials activated from long-term memory stores enter the dream production system (bottom-up process); such materials are elaborated and interpreted by a top-down process. A circular feedback activity, operating between these two components, is able to activate additional mnemonic materials. Some experimental results, concerning the incidence of dream recall in different stages of sleep, show evidence of the continuity of dreaming activity throughout the period of sleep. The relationships between dream and consciousness/awareness are then considered. Experimental data suggest that consciousness, interpreted as awareness (phenomenal awareness; meta-awareness; self awareness), can be present along the whole sleep/dream process, even if many modifications of meta-awareness and of self-awareness are possible. Some hypotheses on the relationship between sleep and dreaming are formulated.