Dream experiences and the neural correlates of perceptual consciousness and cognitive access.

Dreaming may offer clues about whether seeing something requires being able to think about it. The paper examines two lines of argument: one points to low activity in the dorsolateral prefrontal cortex during REM sleep, the other to a general posterior hot zone as the neural correlate of dream experiences. Neither withstands close scrutiny. White dreams—episodes where people report having dreamed but recall nothing—are the most promising phenomenon for settling the debate. Cognitive access is not a single process, and its brain basis remains poorly understood. A form of cognitive access may operate without the dorsolateral prefrontal cortex, and perhaps without any frontal activity. If so, posterior-only activation during conscious experiences could still be compatible with the claim that perceptual consciousness requires cognitive access.

Study at a glance

Abstract

This paper approaches the debate whether perceptual consciousness requires cognitive access from the perspective of dream studies, and investigates what kind of findings could support the opposing views of this debate. Two kinds of arguments are discussed, one that claims that the hypoactivity of the dorsolateral prefrontal cortex in rapid eye movement sleep is directly relevant, and another that proposes that locating the neural correlates of dream experiences can indirectly inform the debate. It is argued that under closer reflection, neither the classical claim about dorsolateral prefrontal cortex hypoactivity nor the more recent emphasis on general posterior hot zone activity during dreaming stand up to scrutiny. White dreaming is identified as the phenomenon that, nevertheless, holds the most promise to have an impact on the debate. Going beyond the topic if studying dreams can contribute to this debate, it is argued that cognitive access is not a monolithic phenomenon, and its neural correlates are not well understood. There seems to be a relevant form of cognitive access that can operate in the absence of activity in the dorsolateral prefrontal cortex, and maybe also in the whole frontal region. If so, then exclusive posterior activation during conscious experiences might very well be compatible with the hypothesis that perceptual consciousness requires cognitive access.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.