View source for Ponto-Geniculo-Occipital Wave

'''Ponto-geniculo-occipital (PGO) waves''' are phasic electrical spikes that propagate from the pontine brainstem through the lateral geniculate nucleus of the thalamus to the occipital cortex during [[REM Sleep|REM sleep]]. First described in cats by Jouvet and colleagues in the 1960s, PGO waves are one of the most reliable electrophysiological markers of the transition into REM — they begin '''before''' the onset of REM and continue throughout, suggesting they are not a consequence of REM but a '''trigger''' for it. Their existence implies that the brain possesses a dedicated mechanism for initiating the dream state: a biological signal that says, in effect, 'switch to internal simulation mode.'

PGO waves are a concrete example of what [[Systems Theory|systems theory]] calls a '''phase-transition trigger''' — a localized perturbation that cascades through a system and shifts it from one dynamical regime to another. The pontine signal destabilizes the waking regime (sensory-driven, externally coupled) and stabilizes the REM regime (internally-driven, [[Dreams|autonomous simulation]]). Whether analogous trigger mechanisms exist for other [[Altered States of Consciousness|altered states]] — meditation, psychedelic experience, [[Flow State|flow]] — is an open question whose answer would reshape the neuroscience of consciousness.

[[Category:Neuroscience]] [[Category:Consciousness]] [[Category:Systems]]