Electrophysiological and phenomenological effects of short-term immersion in an altered sensory environment.

We examined the spontaneous cerebral electrophysiology and phenomenology during short-term perceptual deprivation consisting of an edgeless visual field combined with monotonous auditory input that eliminated potential grounding cues (multimodal Ganzfeld). Subjects (N = 22) were instructed to self-report perceptual fading using a button press. Relaxed wakefulness with closed eyes and viewing of a time-varying stimulus array served as control conditions.

Perceptual phenomena in destructured sensory fields: Probing the brain's intrinsic functional architectures.

Destructured sensory fields, involving homogenous stimulation with little or no time-varying structure, provide a fertile ground for testing hypotheses about predictive coding in the human brain. Extended exposure to sensory patterns that deviate substantially from the statistics of natural environments can elicit a bewildering range of perceptual phenomena, up to and including vivid oneiric imagery. We illustrate how this large variety of perceptual effects can be understood as the experiential counterpart of auto-generated neuronal dynamics, unconstrained by parameters that tune the waking sensorium.