[Developmental changes in hierarchical visual stimulus recognition in children aged 5-10 years].

Reaction time (RT) and performance accuracy in hierarchical visual stimulus recognition at local and global levels were studied in 95 healthy 5-6, 6-7, 7-8 and 9-10-year-old children and 10 adults. Task performance of all examined subjects, both children and adults, was faster and more accurate during global feature recognition (global advantage effect), with increased RT to incongruent stimuli in local condition (global interference effect). Significant inter-individual differences were found in the youngest group (5-6-year-olds): 7 children from the total number of 37 subjects failed to show the global advantage and global interference effects.

[Functional brain organization of global and local visual perception: an ERP study].

Adult subjects were asked to recognize a hierarchical visual stimulus (a letter) while their attention was drawn to either the global or local level of the stimulus. Event-related potentials (ERP) and psychophysical indices (reaction time and percentage of correct responses) were measured. An analysis of psychophysical indices showed the global level precedence effect, i.

[Individual differences in global vs. local visual perception of hierarchical stimuli under conditions of free and forced recognition].

Sixteen adult subjects were asked to recognize hierarchical letters at either local or global levels. The experiment included two sessions, corresponding to free recognition and forced recognition with the attention directed to a specific level of hierarchy. The analysis of recognition errors and reaction time in the condition of free recognition revealed two individual strategies of visual perception: the "global strategy" (the global level was chosen more frequently) and the "local strategy" (the local level was chosen more frequently).

[Characteristics of attention in children with attention deficit hyperactivity disorder (an analytical review)].

The information concerning specific features of different attention components (alertness, sustention and selectivity) in children with attention deficit hyperactivity disorder (ADHD) is analyzed and systematized. According to the data reviewed, behavioral and attention problems described as ADHD are not homogeneous. Literature analysis of attention characteristics in children with ADHD shows that different components can be disrupted if ADHD is diagnosed as inattentive or combined subtype, but the main deficit in this case is that of selective voluntary attention.