Lucid dreaming: Psychophysiological studies of consciousness during REM sleep.

Abstract

Although we are usually not explicitly aware that we are dreaming while we are dreaming, at times a remarkable exception occurs, and we become conscious enough to realize that fact. "Lucid" dreamers (the term derives from van Eeden, 19 13) report being able to remember the circumstances of waking life freely, to think clearly, and to act deliberately upon reflection, all while experiencing a dream world that seems vividly real (Green, 1968; LaBerge, 1985; Gackenbach & LaBerge, 1988). This contrasts with the usual characterization of dreams as states that typically evince no reflective awareness or true volition (Rechtschaffen, 1978). Lucid dreaming is normally a rare experience. Though most people report having had a lucid dream at least once in their lives, only about 20% of the population reports having lucid dreams once a month or more (Snyder & Gackenbach, 1988). Although most people have experienced lucid dreams, some theoreticians have considered them impossible and even absurd (e.g., Malcolm, 1959). In the absence of empirical evidence, most sleep researchers have been inclined to accept Hartmann's (1975) "impression" that lucid dreams are "not typical parts of dreaming thought, but rather brief arousals" (p. 74; see also Berger, 1977). Schwartz and Lefebvre (1973) noted that frequent transitory arousals are common during REM sleep and proposed that these "microawakenings" are the physiological basis for lucid dream reports. Although no one has found any evidence for this mechanism, their proposal has been the predominant opinion (cf. Foulkes, 1974) until the last few years.

Testing the involvement of the prefrontal cortex in lucid dreaming: A tDCS study

“…For example, the stimulation might have increased arousal which could lead to increased lucidity, as lucid dreams are associated with elevated levels of physiological activation during REM sleep (LaBerge, Levitan, & Dement, 1986), or lucidity might be induced due to electro-tactile stimulation effects (cf. Hearne, 1983).…”

“…Awakening after a longer time in REM sleep might also increase the chances for successful eye-signaling (cf. LaBerge et al, 1986).…”

“…Lucid dreaming has been defined as a rare but robust awareness that we are dreaming and that we are not really awake. It is considered to be mainly a REM sleep phenomenon (LaBerge, 1990), although lucidity can also occur during NREM sleep . Hobson et al (2000) have proposed that, during the lucid state, the previously deactivated DLPFC becomes reactivated, allowing directed thought, metacognition and awareness of being while in a dream state.…”

Tempo de cérebro

“…O controle de funções fisiológicas importantes por meio da meditação é reconhecido pela ciência (Wallace, 1970;Elson et al, 1977). Da mesma forma, o controle voluntário da atividade onírica ou sonho lúcido é uma habilidade que começa a ser compreendida cientificamente (LaBerge et al, 1981;LaBerge;Dement, 1982;LaBerge et al, 1986;Brylowski et al, 1989;Voss et al, 2009;Mota-Rolim et al, 2010). Mais perto do eixo central da pesquisa neurocientífi-ca, experimentos de neurofeedback em que os sujeitos experimentais treinam o controle da própria atividade cerebral são realizados com diversas finalidades de reabilitação e terapia (Birbaumer et al, 2009).…”

Problemas en la clarificación del concepto de conciencia

“…Los resultados obtenidos por los investigadores en este campo han permitido conceptualizar la conciencia como algo más que una cuestión de vigilia. Un sueño lúcido es el fenómeno en el que el sujeto, a pesar de encontrarse dormido, es consciente de su estado; incluso puede dirigir su sueño o puede mostrar algún tipo de movimiento o actividad ante demandas dadas por personas ajenas (LaBerge, 1990).…”