Исследование сна и принципы организации коры мозга

Until recently, different areas of cerebral cortex were considered as specialized structures set up to analyze specific modalities of sensory information, such as visual, audial, somatosensory, etc. However, current studies of cortical neuron activity in the sleep/wake cycle show that, during sleep, same group of neurons located in same sensory areas switch to analysis of different visceral system of the body. Thus, e.g., neurons of visual cortex become sensitive to electrical stimulation of the intestine or the stomach, or start to mirror the natural mio-electric activity of these organs. Neurons of other cortical areas may become reactive to the activity of heart or to breathing during particular periods of sleep. After awaking, all such visceral responses disappear and the respective neurons fall back to their usual duty of processing signals from the outer world.
These results suggest to rethink the familiar picture of how the brain is organized, in which the cortex forms the material substrate of consciousness. Indeed, consciousness is absent during the sleep periods, while cortical neurons continue to work actively attending to the visceral demands of the body. Moreover, the anatomical organization of the cortex does not provide for associative capabilities characteristic for conscious brain activity. We suggest that the possible substrate of consciousness is formed by the basal ganglia. This conjecture is in agreement with the experimental data on basal ganglia activity in the sleep/wake cycle.