Conditioned salivation and associated dreams from REM sleep.

Abstract

Although research has investigated the feasibility of establishing classically conditioned physiological responses during sleep, very few experimental studies have considered whether classically conditioned cognitive associations are possible. Since dreams have previously been described as a state of "hyper-association," an experiment involving classical conditioning of the human salivary response and associated dream content was conducted. During wakefulness, repeated pairings of a conditioned stimulus (CS; a red light) with an unconditioned stimulus (UCS; citrus juice) yielded a conditioned autonomic response (CR; salivation) on presentation of the CS alone. After exposure to the CS during REM sleep, salivary excretion rates measured upon awakening were significantly higher than measures taken from baseline REM awakenings. However, no CR-related dreams were reported by the participants. This result could be interpreted as evidence that participants in this experiment did not experience higher-order memory associations to the external stimuli presented during REM. Alternatively, the lack of CR-related dreams could be explained by previous findings that the autonomic nervous system often works independently of higher-order cognitive activity. Therefore, if an autonomic association is formed, this does not necessarily imply a cognitive one.

REM sleep deprivation: The wrong paradigm leading to wrong conclusions

“…For example, within NREM, phasic spinal reflex inhibition was associated with greater recall, auditory imagery, and hostility (Pivik 1991); PIPs (phasic integrated potentials) with enhanced recall (Rechtschaffen et al 1972); and sleep onset theta bursts with discontinuity (Foulkes & Pope 1973). Such potential correlates continue to be identified and include the very rapid eye movements (VREMs) associated with K-complexes (Serafetinides 1991) as well as NREM imagery envoked by external stimuli (Conduit et al 1997). As psychophysiological techniques in sleep research become increasingly sophisticated, it is likely that additional tonic and phasic correlates of sleep mentation will emerge in studies of both REM and NREM (e.g., Germain et al 1999;Miro et al 1999;Paiva & Guimaraes 1999;Rochlen et al 1998;Takeuchi et al 1999a;.…”

“…Auditory stimuli also evoke phasic pauses in diaphragm activity during NREM sleep, another response typically associated with REM sleep (Hunt et al 1998). In human subjects, combined auditory/visual stimulation during NREM sleep produces an increase in the amount of reported dream content (Conduit et al 1997), a finding that prompted Conduit et al to propose that the increase may be brought about by activation of REM sleep PGO activity during NREM sleep. In human subjects, combined auditory/visual stimulation during NREM sleep produces an increase in the amount of reported dream content (Conduit et al 1997), a finding that prompted Conduit et al to propose that the increase may be brought about by activation of REM sleep PGO activity during NREM sleep.…”

“…Antrobus et al 1995;Aserinsky & Kleitman 1953;Casagrande et al 1996a;Castaldo & Holzman 1969;Conduit et al 1997;Dement 1955;Dement & Kleitman 1957b;Fein et al 1985;Foulkes 1962;Foulkes & Pope 1973;Foulkes & Schmidt 1983;Foulkes & Rechtschaffen 1964;Goodenough et al 1959;1965b;Hobson et al 1965;Jouvet et al 1960;Kamiya 1962;Kremen 1961;Lloyd & Cartwright 1995;Moffitt et al 1982;Molinari & Foulkes 1969;Nielsen et al 1998;Orlinsky 1962;Porte & Hobson 1996;Rechtschaffen et al 1963a;Rotenberg 1993b;Slover et al 1987;Snyder 1965;Stoyva 1965;Waterman 1992;Wolpert 1960;Wolpert & Trosman 1958;Zimmerman 1970. Antrobus et al 1995;Aserinsky & Kleitman 1953;Casagrande et al 1996a;Castaldo & Holzman 1969;Conduit et al 1997;Dement 1955;Dement & Kleitman 1957b;Fein et al 1985;…”

“…Such models proposed the existence of phasic sleep processes (primarily PGO waves) underlying the recall of mentation from sleep (see Pivik 1991). Conduit et al 1997). These include: the proximity of NREM sleep awakenings to REM sleep (e.g., Stickgold et al 1994a), REM deprivation effects on NREM recall , drug effects on NREM recall (e.g., Delorme et al 1965) and sensory stimulation effects (e.g.…”

“…Previously, we have proposed that PGO activity might be indirectly related to dream reporting through the phasic activation of arousal, which then provides optimum conditions for the recall of ongoing mentation from sleep on awakening (Conduit et al 1997). Previously, we have proposed that PGO activity might be indirectly related to dream reporting through the phasic activation of arousal, which then provides optimum conditions for the recall of ongoing mentation from sleep on awakening (Conduit et al 1997).…”