Virtual reality and consciousness inference in dreaming

Abstract

This article explores the notion that the brain is genetically endowed with an innate virtual reality generator that – through experience-dependent plasticity – becomes a generative or predictive model of the world. This model, which is most clearly revealed in rapid eye movement (REM) sleep dreaming, may provide the theater for conscious experience. Functional neuroimaging evidence for brain activations that are time-locked to rapid eye movements (REMs) endorses the view that waking consciousness emerges from REM sleep – and dreaming lays the foundations for waking perception. In this view, the brain is equipped with a virtual model of the world that generates predictions of its sensations. This model is continually updated and entrained by sensory prediction errors in wakefulness to ensure veridical perception, but not in dreaming. In contrast, dreaming plays an essential role in maintaining and enhancing the capacity to model the world by minimizing model complexity and thereby maximizing both statistical and thermodynamic efficiency. This perspective suggests that consciousness corresponds to the embodied process of inference, realized through the generation of virtual realities (in both sleep and wakefulness). In short, our premise or hypothesis is that the waking brain engages with the world to predict the causes of sensations, while in sleep the brain’s generative model is actively refined so that it generates more efficient predictions during waking. We review the evidence in support of this hypothesis – evidence that grounds consciousness in biophysical computations whose neuronal and neurochemical infrastructure has been disclosed by sleep research.

Predictive coding and representationalism

“…On this view, organisms can engage in a sort of fictive, counterfactual sensory sampling of the world, and this process could underlie the ability to preselect actions; the assumption is that those actions will be executed which are predicted by the model to be most effective at reducing uncertainty about external causes of the sensory signal (although the idea of counterfactual sampling may have other applications as well, for example when it comes to explaining the phenomenal experience of perceptual presence; see Seth 2014). On the other hand, it has been proposed that PCT can explain multiple aspects of REM dreaming (Hobson and Friston 2012;Hobson et al 2014). Roughly speaking, the claim here is that during REM sleep, the brain uses generative models of the world to construct off-line simulations of counterfactual scenarios in a way that is totally freed from the "sensory enslavement" of signals coming from the world.…”

“…Recognition of the first type of error-that which results from inaccuracies in the generative model itself-corresponds to situations where the system modifies not its current perceptual hypothesis, but the hypothesis space (the generative model) as such. This seems to be the case when the structure of the model parameters is modified and adjusted in light of the prediction error (a process of Bayesian perceptual learning; see Clark 2013b;Friston 2003) or when the system attempts to minimize the overall complexity of the model (Hobson and Friston 2012;Hobson et al 2014). Recognition of the second type of error corresponds, straightforwardly, to perceptual inference-an ongoing process in which the system revises its current hypotheses (and not the model itself) about the causal etiology of an incoming sensory signal.…”

Opposite Impact of REM Sleep on Neurobehavioral Functioning in Children with Common Psychiatric Disorders Compared to Typically Developing Children

“…Rapid eye movement (REM) sleep is characterized by bizarre dreaming consciousness upon lack of external input (Hobson, 2009; Nir and Tononi, 2010), which is accompanied by specific neurophysiologic signatures including wake-like low frequency desynchronized electroencephalogram (EEG) dominated by theta and gamma EEG oscillation, swift occurrence of REMs and pontine-geniculate-occipital waves and absence of muscle tone (Rechtschaffen and Kales, 1968; Hobson and Pace-Schott, 2002; Hobson et al, 2014). Remarkably, amongst all sleep-wake stages, REM sleep has a prominent role in enabling neuronal plasticity, increased synaptic connectivity, and immediate early genes synthesis (Ribeiro et al, 2002; Grosmark et al, 2012) and is signified by a strong cortical activation (De Gennaro et al, 2004; Massimini et al, 2010).…”

Rapid Eye Movements (REMs) and visual dream recall in both congenitally blind and sighted subjects

“…Moreover, studies in human subjects suggest that REMs are visually targeted eye movementscommanded by the forebrain -in response to visual dream images and that REMs are involved in both the scanning and generation of dream imagery 51 .…”