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Automaticity of saccades and a sleep
Above we have reviewed examples of a functional role of saccadic automaticity under wake.
However, our investigations showed that during sleep the number of saccades remains the
same as under wake. Why are saccades needed if the eyes are closed and there is no necessity
to see either a visual picture or compensate defects of a sensor apparatus? Of course, it
is convenient for clinicians to identify sleep phases according to presence or absence of
saccades, as just because of them they accurately define the stage of sleep named as the
phase of a rapid eye movement (RYM). But evidently the Nature in a less degree was
interested in a medical practice as the nature had more serious tasks. Which are they?
We have all grounds to think that saccadic automaticity can be regarded as an
mechanism". Saccade is not large in amplitude but its excitation wave runs through all brain
structures up to the cortex. It happens every half second and every time the excitation
wave penetrating through nervous structures breaks off the links established between nervous
cells under wake. Due to that saccades destroy reverberating links and prevent from
consolidation of nervous cells into large structures which could dominate at the moment.
The latter is extremely important for the whole organism as consolidation of nervous cells
into large systems when excited synchronously can lead to epileptic seizure.
We named this saccadic function "antimonopoly" by analogy with principles of a market
economy. Just as in economics antimonopoly committees do not give a chance to separate
concerns to dictate their conditions to the whole industry, the saccades "deprive of
rights" separate brain structures "to impose their will" on other structures. This is one
more example of the work of large systems according to general laws: let it be biological
or social systems. What is good for the brain as a system, a discrete element of which
is a nervous cell, is good for the economy of the country, a discrete element of which
is an individual person.
During slow sleep stage when there are no saccades and "antimonopoly mechanism" does not
work, nervous cells can easily integrate into large groups. Clinicians know well that just
at that stage of sleep very often epileptic seizures happen. It means that integration of
nervous cells reached a critical value. "Antimonopoly" mechanism of saccadic automaticity
can work not only during sleep but under wake as well.
While studying that process we noted the decrease of visual fatigue in computer operators
when they for some time were tracing a moving spot on the screen. That procedure resulted
in increase of saccades and their amplitude, which in its turn destroyed the links
established during intensive visual work. It is possible that an operator anticipating an
epileptic seizure could weaken the seizure or even avoid it by arbitrary increase of
saccades shifting the gaze from one object to another or moving the eyes to the right and
to the left.