States of consciousness Prof. dr. Anton M.L. Coenen NICI – Department of Biological Psychology...
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Transcript of States of consciousness Prof. dr. Anton M.L. Coenen NICI – Department of Biological Psychology...
States of consciousness
Prof. dr. Anton M.L. Coenen
NICI – Department of Biological Psychology
Radboud University Nijmegen
The Netherlands
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.
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.
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
THE POSITIVE EFFECT OF SLEEP ON MEMORY
THE INTERFERENCE HYPOTHESIS
THE REM-SLEEP HYPOTHESIS
THE SEQUENTIAL HYPOTHESIS
THE 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.