Perception as an active mental activity is a multiunit system including different interacting brain structures, each of which is specifically involved in individual sensory and cognitive processes [1][2][3][4][5]. Ontogenetic studies substantially contribute to the investigation of visual perception. Heterochronous maturation of brain structures in ontogeny reveals certain stages of the formation of the brain organization of this function. These stages determine age-related features of various visual operations such as analysis of the properties of an object, their multimodal convergence, identification, assessment of significance, and decision making in accordance with the motivation for perceptive activity [6][7][8].This article considers the mechanisms of visual perception at various ontogenetic stages and the formation of the mature type of perception.Reaction to visual stimuli in newborns. An evoked response with the main components of the sensory-specific adult evoked potential (EP) is already recordable from the first hours of life and is most pronounced in the primary visual projection cortex [9]. Although the time characteristics of the EP are much higher than the corresponding indices of the adult response, its localization and relative stability are indicative of its sensory-specific nature, and its long latency may be a result of conduction by pathways nonmyelinated as yet [9,10]. The cortical origin of the positive EP component was confirmed by cytomorphological studies of the cortical visual fields, which demonstrated that neurons located in cortical layers IV and V and providing two-way corticosubcortical connections are best differentiated in the primary visual area [11,12]. Moreover, immature forms of interneurons (fusiform and stellate cells), which are heavily involved in sensory analysis, can be found in these cortical layers from the moment of birth [13].The involvement of neurons of deep cortical layers in the reception of external information is reflected in the initial positive EP component. In preterm children (born at a gestational age of less than 30 weeks), the positive EP component is absent [14,15]. It is interesting that, some time later, their EP appears as more mature as compared to the corresponding EP in fullterm children of the same conceptional age [15]. This finding provides strong evidence for the influence of environmental factors, in this case, of the visual experience, on the structural and functional maturation of the brain cortex.In the newborn period, eye movements are of considerable importance in perception of visual information. It is known that the eyes of newborns turn towards a light source. A possible involvement of the brain cortex in oculomotor reactions was demonstrated during simultaneous recording of the visual EPs and the optomotor reactions of the opening and closing of the palpebral fissures [16]. Two types of optomotor reactions to a light flash were revealed: asynchronous eye movements with a short latency (50-70 ms) not preceded by a cortical EP and m...

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