**3. Particularities of non-verbal visual gnosis in the pre-school period**

Ontogenetic research has made a major contribution to the study of visual perception. They define the stages of its formation, taking into account the mechanism of heterochronic maturation of brain structures. The data show that the transition from 5 to 6 to 7–8 years of age should be seen as a period of intense maturation of the fields related to visual information analysis. At the same time, complicated forms of visual gnosis (identifying images in difficult conditions) are not sufficiently developed due to the later inclusion of regulatory brain mechanisms.

Event-related potential studies of children with a typical development show significant differences in the system of perception of visual information before and after age 5 [32, 33]. It is found that at earlier stages the visual perception processes have diffuse characters, since similar reactive and configuration event-related potentials are recorded in all caudal regions. This explains the difficulties of the children in tasks to integrate signs and reproduce the overall images of objects [34]. After 5 years of age, a process of structuring and lateralization of visual perception processes begins. This is evidenced by differences in reactivity to individual components of event-related potentials in the projection and associative visual areas of the cortex. The data show an increasing specialization of post-center associative departments in the processing of complex visual stimuli, which improves analysis and discrimination of features when forms and building standards for complex images are compared.

Visual analysis in difficult conditions (recognition of imposed shapes and incomplete images) is only possible in a time-shared hemisphere interaction from left to right, where the same object is analyzed first on the left and then on the right hemisphere. Levashov suggests the

**1.** The visually received image is processed by the left-hemisphere mechanisms for schematic recognition (classification). In cases of insufficiently known objects, inter-hemispheric associative links and corresponding structures from the right hemisphere are activated. Engaging a certain area of memory naturally narrows the search area among the engrams

**2.** The view is moved so that the projection of the analyzed plot falls into the right hemisphere in which the visual working memory is concentrated and neural structures (engrams) of each object class are stored. The input image is matched with the activated animations and leads to the categorization of the object. In complex and weakly known objects, recognition

Through studies with event-related potentials in identifying hierarchical visual stimuli [28], two types of recognition are distinguished—local and global. Local-level recognition is related to the activity of the inferior temporal and prefrontal cortex of the right hemisphere and leads to an assessment of the sensory qualities of the stimuli. At the global-level recognition, the activity of the parietal cortex of the right hemisphere is guided by the inclusion of mechanisms of early sensory selection. Global perception is supposed to be related to the operation of the dorsal visual system and the spatial analysis of the objects. In contrast, perception on a local level (ventral visual system) is directed to the analysis of the elements and properties of the objects. According to some authors [29] of the initial stages of visual perception, the processes are not sufficiently lateralized. They become such at the higher levels of visual analysis

In recent years, the role of feedback on the functioning of cognitive processes has been increasingly discussed. The data show feedback between secondary and primary vision fields and demonstrate the modulation action of the top-down mechanism [30, 31]. Reverse connections are assumed to stimulate the activity and spatio-temporal dynamics of large groups of neu-

**3. Particularities of non-verbal visual gnosis in the pre-school period**

Ontogenetic research has made a major contribution to the study of visual perception. They define the stages of its formation, taking into account the mechanism of heterochronic maturation of brain structures. The data show that the transition from 5 to 6 to 7–8 years of age should be seen as a period of intense maturation of the fields related to visual information analysis. At the same time, complicated forms of visual gnosis (identifying images in difficult conditions) are not sufficiently developed due to the later inclusion of regulatory brain

following possible scheme of this interaction in the resolution of visual tasks:

is done by moving the view to other informative points from them.

when stimulus processing acquires asymmetric organization.

rons associated with the integration of visual information.

mechanisms.

in long-term viewing memory.

26 Prefrontal Cortex

In the period of 5–6 years, changes in the structural organization of neuronal ensembles in the caudal cerebral regions result in a qualitatively new functional organization of visual perception [35]. In children aged 6–7 years, in the realization of visual gnosis are included structures of the frontal partition, which is the beginning of its intellectualization. The identification of difficult-to-verbalize stimuli is associated with greater reactivity of structures from the temporal and occipital parts. When recognizing stimuli with a simple verbal formulation, the reactivity is shifted to the frontal lobe.

Dorsolateral prefrontal cortex is a high regulatory center and plays an important role in manipulating visual information. The insufficient maturity of the dorsolateral mechanisms during this period explains the weak reactivity of the negative wave, reflecting the cognitive component of visual recognition. The limited involvement of the prefrontal cortex in the analysis of incomplete images suggests a poor development of the regulatory component of perception during pre-school age. New research suggests that the complex of P200-N250 waves in the visual cortex, which is considered to be key in recognizing signs, shows a significant increase in the caudal and precentral cortical divisions after 7–8 years of age [36, 37]. In adults, it is most expressed in the post-temporal parts, which are part of the ventral visual system and play a major role in recognizing fragmented images.

Neurophysiological studies in complicated perceptual conditions of children show a leading activity of the occipital segments and a lack of significant increase in event-related potentials in the post-temporal regions [38, 39]. It is also stressed that at the age of 5–6 years, components of event-related potentials in the prefrontal cortex are not recorded. According to some authors [35], the low efficiency of fragmented image identification in this period is due to both the immaturity of the prefrontal cortex and the deficiencies in the functioning of the visual system. The low level of recognition under conditions of perceptual deficit is explained by the underdevelopment of regulatory mechanisms and insufficient involvement of the ventral visual system. In the period of 7–8 years, the role of the ventral visual system increases; this corresponds to the morphological data for significant transformations in the neuronal organization of the posterior temporal areas [39]. There is currently no unified opinion on the mechanisms of recognizing incomplete images in children. According to neurophysiological data in the period of pre-school and early school age in their brain organization there are both similarities and differences. Similarities refer to prefrontal cortex involvement in early stages of the analysis of complex visual stimuli. The differences reflect the underdevelopment of the regulatory components of visual recognition in the pre-school period, shown by the large number of mistakes in children aged 5–6 [34].

regions. Neural processes responsible for mental "filling--in" the missing information in visual incentives, some authors [37] mean by the term "perception of closing". The phenomenon is a combination of areas known as the lateral-occipital complex (LOC) that is linked to a wide network of dorsal and frontal regions. Studies with functional magnetic resonance imaging (fMRI) confirm the leading role of the lateral-occipital complex in detecting hidden objects [43]. The sample we use contains 12 black and white incomplete images of objects (lamp, sword, spoon, anchor, pliers, kettle, teapot, needle, key, guitar, scissors and ring). Some of them are

The Dynamic Maturation Process of the Brain Structures, Visual System and Their Connections…

http://dx.doi.org/10.5772/intechopen.79169

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presented below (**Figures 1**–**4**).

**Figure 1.** Lamp.

**Figure 2.** Anchor.

**Figure 3.** Teapot.

Testing through event-related potentials for perceiving fragmented shapes in children aged 5–6 years separates two subgroups: A subgroup with a small number of errors and a B subgroup with a large number of errors [26]. In the second subgroup, a delayed development of two systems was recorded: the ventrolateral visual system and the dorsolateral prefrontal cortex responsible for regulatory functions and in particular for inhibitory control. Inhibitory control determines the successful recognition of the figures, whereas its absence explains the impulsive responses of children with low scores. The conclusion is that the morpho-functional maturity of the neuron systems processing sensory information and the state of regulatory functions determine children's individual abilities to visual recognition and their readiness for school education.

The image identification in conditions of sign shortness assesses the functioning of the righthemisphere mechanisms and the implementation of a holistic perceptive strategy and is one of the most complex gnostic tasks. Difficulties in building hypotheses by children explain the cases of refusal to name individual figures and the presence of perseverations (use of a single word for different images).

The analysis of the existing data sets the period of 4–6 years as sensitive for the development of brain mechanisms for perceptive processing and for the formation of complex forms of visual gnosis. The specifics in the functioning of the gnostic operations in children with typical development in pre-school age have an important diagnostic and prognostic significance since the evocation of normative data allows for the separation of subgroups with different levels of perceptual functions and the differentiation of children at risk of learning difficulties. This is in line with the thesis [40] that any neuropsychological study in childhood pursues two purposes: the diagnosis of the condition of the function and the formulation of the treatment methods and approaches.
