by Aleksei IVANITSKY, Corresponding Member of Russian Academy of Sciences, Head, Laboratory of Higher Nervous Activity of Man, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences How do brain and consciousness correlate? How is a subjective world of a human being formed on the basis of nerve pulses? For a long time this problem was considered to be the domain of philosophy and other humanitarian disciplines. Only in recent decades the natural scientific approaches to its solution were discovered. MECHANISMS OF SENSATIONS Consciousness is the priority function of the brain*. In fact, it is our life, consisting of alternating impressions, thoughts, and sensations. But how rightful is it to explain what we perceive as color, sound, emotion by the motion of nerve pulses? Despite seeming complexity, this problem of nature is not unique in its methodological difficulty and is one in a series of other mysteries of the universe. Two main approaches to search for cerebral mechanisms of consciousness, not ruling out, but supplementing each other, can be distinguished. One is the concept according to which subjective experience emerges on the basis of forward propagation of stimulation from primary zones of the cerebral hemispheric cortex to higher structures, one of which, and a most important one, is the frontal cortex. It has three unique characteristics: capacity for operations with abstract symbols, memorization of the time sequence of real events, and presence of speech centers. These three qualities directly correlate with the signs of consciousness. The other approach is based on a hypothesis that subjective experience is a result of certain organization of cerebral processes and comparison of new information with the information extracted from memory, in the cortical zones. Due to this, the picture of external events is as if projected to the subject's individual experience, incorporating in the personal ... Read more