Towards a Functional Understanding of PGO Waves

Abstract

Ponto-Geniculo-Occipital (PGO) waves are biphasic field potentials identified in a range of mammalian species that are ubiquitous with sleep, but can also be identified in waking perception and eye movement. Their role in REM sleep and visual perception more broadly may constitute a promising avenue for further research, however what was once an active field of study has recently fallen into stasis. With the reality that invasive recordings performed on animals cannot be replicated in humans; while animals themselves cannot convey experience to the extent required to elucidate how PGO waves factor into awareness and behavior, innovative solutions are required if significant research outcomes are to ever be realized. Advances in non-invasive imaging technologies and sophistication in imaging methods now offer substantial scope to renew the study of the electrophysiological substrates of waking and dreaming perception. Among these, Magnetoencephalogram (MEG) stands out through its capacity to measure deep brain activations with high temporal resolution. With the current trend in sleep and dream research to produce translational findings of psychopathological and medical significance, in addition to the clear links that PGO wave generation sites share, pharmacologically, with receptors involved in expression of mental illness; there is a strong case to support scientific research into PGO waves and develop a functional understanding of their broader role in human perception.

Rapid Eye Movements in Sleep Furnish a Unique Probe Into Consciousness

“…Magnetoencephalography (MEG) is a promising tool to study regional activity changes time-locked to REMs in sleep ( Gott et al, 2017 ), in particular, multisensory-motor integration as well as PGO waves ( Ioannides et al, 2004 ). MEG has good spatial resolution (millimeters precision) and a very high temporal resolution (milliseconds precision).…”

How rhythms of the sleeping brain tune memory and synaptic plasticity

“…PGO waves, like NREM spindles, occur as discrete biphasic wave events during sleep (as intermittent single waves during certain phases of NREM, and as repeating motifs throughout REM; Figure 3, right) [134,135]. These high waves of activity propagate (as the name implies) through the pons, the lateral geniculate nucleus of the thalamus, and the occipital cortex of species with highly developed visual systems, and propagate from the pons to apparently communicate with numerous brain structures (and are thus simply called "P waves") in rodents [136]. A role of this wave in sleep-dependent memory consolidation (particularly for hippocampus-and amygdaladependent memories) has been extensively investigated in rodents.…”

A model of Ponto-Geniculo-Occipital waves supports bidirectional control of cortical plasticity across sleep-stages

“…Interestingly, the transitional stage from non-REM sleep to REM sleep (referred to as pre-REM stage), and the subsequent REM sleep stage are associated with the occurrence of another family of phasic events, Ponto-Geniculo-Occipital (PGO) waves (Steriade et al, 1989; Gott et al, 2017). A typical PGO wave displays biphasic waveforms in Local Field Potential (LFP) activity traces, comprising of a fast-negative component preceding a slower, weaker positive component, possibly followed by smaller fluctuations (Gott et al, 2017; Callaway et al, 1987; Datta, 1997). PGO waves are named after three key structures where their propagation is most frequently observed: the Pons, the Lat-eral Geniculate Body of the thalamus and the Occipital cortex (Jouvet, 1959).…”