States of consciousnessProf. dr. Anton M.L. Coenen

NICI – Department of Biological Psychology

Radboud University Nijmegen

The Netherlands

a.coenen@nici.ru.nl

States of consciousness

• Lecture 3. Enigmatic states of consciousness: REM sleep and dreaming

Birth Conception Age in years

1 10 200

REM sleep

Non-REM

hour

s10

16

24

Baby

Adult

Eugene Aserinsky and Nathaniel Kleitman (1921-1998) (1895-1999)

From left to right, Michel Jouvet, William Dement, Nathaniel Kleitman and Eugene Aserinsky, after their symposium on the discovery of REM sleep on June 1, 1995. The symposium commemorated the 100th birthday of Nathaniel Kleitman in April of 1995.

After Glenn and Steriade, 1982

After Hirsch et al, 1983

(after Morrison, 1983)

Kekulé’s dream

One famous dream – of the Frenchman Alfred Maury – seems to show that dreams are almost instantaneous. He saw himself, a victim of the Franch Revolution,

being tried and sent to the guillotine.He felt the knife fall – and then awoke to find the bedrail had fallen on his neck.

Sigmund Freud is shown here with his daughter Anna,

who herself became an influential psychoanalytic theorist.

After Fischer et al, 1965.

Diagram of the spinal control of penile erections (After Hirshkowitz and Schmidt, 2005)

Brain areas, lateral part of frontal cortex and medial part of parietal cortex,that are less active during REM-sleep than during wakefulness (in red).

The cerebral Blood flow in the medial prefrontal is similar during wakefulness and REM sleep and is decreased during SWS (after Maquet et al, 2005)

  COGNITIVE THEORY ON DREAMING AND REM-SLEEP INFORMATION PROCESSING: SELECTION OF RELEVANT INFORMATION FOR CONSOLIDATION IN LONG TERM MEMORY

After Jenkins and Dallenbach, 1924

THE POSITIVE EFFECT OF SLEEP ON MEMORY

THE INTERFERENCE HYPOTHESISTHE REM-SLEEP HYPOTHESISTHE SEQUENTIAL HYPOTHESISTHE SLOW-WAVE SLEEP HYPOTHESIS

Cortical activation (W and REMS) and slow wave promoting (SWS) systems. The excitatory pathway of the arousal system emerges from the brainstem RF to ascend along a dorsal trajectory into the thalamus upon the non-specific thalamo-cortical projection system and a ventral trajectory through lateral hypothalamus up to the basal forebrain, with widespread projections to the cerebral cortex.

Neurons containing GABA, also located in the basal forebrain, give rise to inhibitory cortical projections. They discharge maximally with slow waves and minimally with fast waves. (after Jones, 2002)

• REM-sleep is an active state of the brain, periodically occurring during slow wave sleep

• During REM-sleep specific parts of the brain are activated, such as the limbic system, and the visual and motor cortical areas. The pons is the generator of REM-sleep. The prefrontal lobe is de-activated.

• REM-sleep is highly associated with dreaming, but, it is not clear whether REM-sleep serves an own (unknown) function (activation-synthesis hypothesis, cognitive theories) or that it serves to generate dreams with its own function (psychoanalytic theories).

•REM-sleep, in association with dreaming, must be regarded as a third, natural occurring state of consciousness.