[Systems approach to the stability and plasticity of neurophysiological processes during the adaptive activity of the brain].

The problem of stability and plasticity of regulatory processes is presented from the standpoint of N. P. Bechtereva's theory of stable pathological state, rigid and versatile links in regulating systems, and the necessity of probabilistic approach is emphasized. Data on connection among separate components of biorhythms in physiological systems and on stability of their frequency-amplitude parameters, are reviewed. The data obtained reveal advantages of using functional bioregulatory feedback methods in clinic.