G.B. Milovanova - Ph.D.(Biol.), Senior Research Scientist, Institute of High Nervous Activity and Neurophysiology of RAS, Moscow
R.A. Maraguei - Research Scientist, Institute of High Nervous Activity and Neurophysiology of RAS, Moscow
L.A. Potulova - Ph.D.(Biol.), Senior Research Scientist, Institute of High Nervous Activity and Neurophysiology of RAS, Moscow

In practice the evaluation of the functional state of man-operator can be caried out basing on the results of his operations compared with the results of initial training. However there are situations when highly motivated man-operator can maintain constant level of quality of the operations by means of willpower efforts although the functional state of the subject begins to significantly deviate from the normal (f.e., during the fatigue development). In such cases the physiological cost of work inceases while both an efficiency and reliability of the operations decrease. By monitoring only parameters of operations (such as the amount, quality and timing, the number of errors and the ability to correct ones, reporting on functional state etc.) it is difficult to foresee and prevent a disruption of compensation which may occur unexpectedly and quickly. That is why the dynamic monitoring the parameters of operations and functional characteristics while the man-operator performs his operations is particularly effective in this case. Namely this technique of monitoring gives an indication of the physiological cost of work, of the health of man-operator and his reliability. Our study shows the results of long-term experiments in which quality and reliability of the recognition of visual images and the behavior of physiological parameters (heart rate interval and the relative time of the closed eyes) were analyzed. It was shown that errors of recognition may vary insignificantly (within limits) a long with experiment session while there is a significant increase of the physiological cost of recognition that denotes a decrease in the reliability of man-operator during his activity.