Contrast Sensitivity of Visual System in 5-Day “Dry” Immersion with a Course of High-Frequency Electromyostimulation

We aimed to study the sensitivity of the visual system in 5-day “dry” immersion (DI) with a course of high-frequency electromyostimulation (HFEMS). The contrast sensitivity of the visual system was estimated in different spatial frequency ranges, indicating the functional state of the magnocellular and parvocellular neuronal systems that form the dorsal and ventral pathways from the occipital to the frontal regions of the cerebral cortex. The power of visual illusions was also assessed using a motor response by “tracing” (with and without visual feedback). Six volunteers were tested before the onset of immersion, on the 1st, 3rd, 5th days of DI, and also after its completion. Every day, the volunteers were exposed to HFEMS. It is shown that there are no significant changes in the contrast sensitivity of the visual system in the low spatial frequency range, to which the magnocellular system is specific, when the conditions of gravity change (gravity–microgravity–gravity), compared with immersion without additional influences. It can be assumed that HFEMS, increasing the afferent flow under conditions of its deficit during support unloading, normalizes the interaction of the dorsal and ventral visual pathways.