During development, the brain creates multilevel feedback loops critical for the generation and maintenance of consciousness. The thalamus has a central role in these circuits. Thalamic core nuclei are part of sensory circuits that give rise to contents of experience; diffuse thalamic matrix nuclei are part of arousal circuits that modulate levels of wakefulness. While core and matrix circuits could be considered part of a single brain system underlying conscious experience, they can also be seen as discrete, parallel circuits responsible for content and consciousness, respectively. Reverberations in thalamocortical core circuits, driven by tasks and conditions, encode content. Reverberations in matrix circuits, driven by circadian rhythms and the “value” of experience, encode fluctuations in arousal levels. This paper considers contributions of quantum events at cellular levels to activation in thalamic matrix circuits. Considering both quantum and classical brain processing gives insight into the relation of brain functioning and consciousness

Quantum effects; thalamic loops; consciousness; matrix cells