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A concept of saccade automaticity was formulated by V.A.Filin in 1987.

Automaticity of saccades is a property of a human oculomotor apparatus to make involuntary quick eye movements (saccades) in a definite rhythm under a wake condition, absence of visual objects and during paradoxical stage of sleep.

The character of saccade movement is caused by the activity of the central nervous system, the structures of which are able generate a signal of automatic type i.e. capable of rhythmogenesis. Every person has its individual pattern of saccade movement determined by three parameters: an interval between saccades, their amplitude and orientation (fig.9).

Fig. 9 Distribution of intervals between saccades under various observation conditions. 1 and 2 - during babies' and adult's quick sleep respectively (470 and 2343 intervals between saccades processed, 7 and 3 subjects); 3 and 4 - fixation of a steady and virtual dots respectively (2362 and 1215 intervals between saccades processed, 11 and 8 subjects); 5 - free seeing of a picture (2000 intervals between saccades processed, 5 subjects); X-axis - intervals between saccades, s, Y-axis - number of measurements, %

The maximum of saccades follows in 0,2-0,6 sec, the amplitude changes in a great range of 2 angle/min to 15angle/grade. Saccades are oriented practically in all directions (right, left, up, down) but as a rule they are more concentrated on a horizontal level. The saccade parameters are modulated by internal and external conditions. For instance, on a fixed point the amplitude is minimized (2-15 angle/min), under fixation in darkness when visual objects are absent the amplitude increases double-triple, under visual perception of the environment up to 86% of saccades have the amplitude up to 15 angle/grade. The changes in the interval between saccades are minimal. Under norm saccades are oriented evenly in one and the other side.

Until our findings the origin of saccadic movements was regarded as a determined process caused by some motivation. We were the first to prove the concept of saccade automaticity (Filin, 1987), where saccade generator is a saccadic center that has a property of rhythmogenesis. Due to that property saccades have a definite rhythm and a characteristic pattern. At that the parameters of saccades are modulated against internal and external conditions and the saccade pattern changes under the influence of unfavorable factor of the visible environment.

The most solid argumentation in favor of the concept of saccade automaticity is the presence of saccades in all groups of tested persons irrespective of age and state of health. The most of the intervals between saccades are in the range 0,2-0,6 sec. It is so called a working regime of saccade automaticity found in those tested with normal vision, with weak vision, the blind, with strabismus and brain pathology (total 410 persons). Besides, the curves of distribution intervals between saccades under different conditions were close in all diapason i.e. under fixation of a real and imagenery points in darkness, during sleep of adults and newborns, under viewing a painting (Fig. ?-). All curves had a single-mode distribution maximum in the range of 0,2-0,6 sec. (Filin V.A., 1990).

Consequently, the saccadic system works as a unified formation generating approximately an equal number of saccades in a time unit. Depending on environmental and internal conditions orientation and amplitude of saccades are changing, i.e. parameters of saccade automaticity are modulated by a concrete situation.