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Automaticity of saccades -->
How do we see by random saccades?
While analyzing distribution of intervals between saccades one can see that this process
obeys to Pausson law of distribution. And this as known, means that the process of saccadic
movement is incidental. A question emerges: How can a person see the area by irregular
saccades?
Evidently it is possible due to the fact that the number of saccades is great. As a rule
saccades happen every 0,2-0,6 sec and only in some cases the intervals make up 3 sec. In
that time there happen no essential changes in the environment. In extreme cases the
number of saccades can increase as it happens with a driver who gets in a traffic jam.
To understand the meaning of irregular incoming afferent impulses one can turn to theoretical
conception of I. Prigozshin, an outstanding expert on "irregular processes". According to
his concept irregular processes have great advantages over regular ones. Just irregular
processes have the ability to generate new qualitative properties unlike regular processes.
Hence we can state that irregular saccadic movements originate new qualities in the very
process of visual perception. One important point can be already stressed: this is a
"antimonopoly mechanism" of saccades. Just irregular saccades can prevent the integration
of nervous cells into large formations and in that way to prevent epileptic seizures
whereas regular saccades could create rhythmic afferent signals that in its turn could
contribute to the process of integration and creation a critical situation i.e. epileptic
seizure.
The existence of a definite time domain necessary for realization of this or that
neurophysiological processes (duration of microact, time for decision making, time for
neurons release, duration of afterimage) has led many investigators to the idea of cyclic
visual perception. Data about saccadic suppression of perception (Steinman R.M.,
Collwijn H. 1980) confirmed that idea: a human can well see only in the interval between
saccades. At the moment of the saccade inhibition of a visual process comes. In other words,
we see discretely or cyclically. A permanent mechanism of recurrence is a saccadic
automaticity.
The attempts to connect the cyclic perception with eye movement were made before
(Pavlov I.P., 1949; PodviginN.F., Makarov F.N., Shelepin Yu.E., 1979) but the conception
of deterministic nature of saccadic eye movement always prevailed. In that case
recurrence could "work" only from time to time when a chance turns up. It could
have been absolutely unreliable mechanism of cyclicity. Saccadic automaticity and
winking automaticity split up a permanent sensation on a number of separate acts
in order, as I.M.Sechenov said, "to combine separate moments of sensation with each
other in a single whole". Taking into account the concept of saccadic automaticity the
idea of cyclic visual perception becomes perfect. There are grounds to state that
winking automaticity also contributes to cyclic visual perception.
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