Consciousness and cognition
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The neuroanatomical substrates controlling and regulating sleeping and waking, and thus consciousness, are located in the brain stem. Most crucial for bringing the brain into a state conducive for consciousness and information processing is the mesencephalic part of the brain stem. This part controls the state of waking, which is generally associated with a high degree of consciousness. ⋯ Evidence exists that this type of sleep, associated with dreaming, with some kind of perception and consciousness, is involved in processing of "internal" information. In line with this, rapid eye movement sleep has higher correlation dimensions than slow-wave sleep and sometimes even higher than wakefulness. It is assumed that the "near-the-threshold" depolarized state of neurons in the thalamus and cerebral cortex is a necessary condition for perceptual processes and consciousness, such as occurs during waking and in an altered form during rapid eye movement sleep.