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The formation of selective sensitivity to the movement of the environment at different velocities still remains an unsolved problem. It is assumed that the basis of the creation of such sensitivity can be as processes of inhibition and facilitation at different levels of the visual system. We studied the role of GABA-ergic inhibition in shaping the velocity tuning by affecting GABA antagonist iontophoresis, bicuculine on responses that occur in 80 neurons of the superior colliculus (SC) on the movement of the light spot at 5-45 degrees/s in hamsters anesthetized by urethane. After the bicuculine iontophoresis compared with the controls 30% of units have changed the velocity tuning category; 61.25% of neurons modified their velocity selectivity more than 10%; 8.75% of cells were found without similar changes. These data suggest that the intracollicular GABA-ergic chains are involved in the formation of velocity tuning of SC-neurons.

This research aims to study the nonlinear dynamics of the brain electrical activity in the performance of complex auditory-motor choice reaction. The boys with obtained visual dysfunction (n = 27, vis. OS 0,70 ± 0,04, vis. OD 0,56 ± 0,05 with correction) and normal sighted (n = 27) boys aged from 8 to 12 years were examined. Nonlinear parameters such as embedding dimension, correlation dimension, Lyapunov maximum exponent and Kolmogorov-Sinai entropy were determined. The auditory-motor integration are induced the activation of the right occipital area and the deactivation of the left occipital area in boys with obtained visual dysfunction. This is not typical for the sighted boys. The results are discussed in the context of cross-modal plasticity and supramodal brain organization.