Neurophysiological indicators of action quality at solving verbal and nonverbal tasks.

Neurophysiological mechanisms of recognition of verbal and nonverbal stimuli have been studied. It was determined that subjects solved nonverbal tasks faster and more effectively with their left hands, while they used two strategies of recognition to solve verbal tasks (fast reactions with right and left hand). Analysis of spectral characteristics of EEG revealed that mechanisms of both anterior and posterior attention systems were simultaneously involved in the process of effective recognition of nonverbal stimuli and ineffective recognition of verbal stimuli. Analysis of the event-related potentials (ERPs) showed that ineffective recognition of verbal and nonverbal stimuli resulted in an increase in the amplitude of sensory components of ERPs (N1m, P1m), while effective recognition increased the amplitude of cognitive components of ERPs (P2m, P3m).

Neurophysiological mechanisms of complex arithmetic task solving.

A new method for identification of stages in arithmetic task solving has been presented. Solving of addition tasks induced formation of EEG foci in delta-theta-band were formed in fronto-central and parietal regions of the left hemisphere and in parietal-temporal and frontal areas of right hemisphere. In multiplication tasks, delta-theta-foci were formed in frontal, central and parietal regions of the left hemisphere as well as in temporal areas of the right hemisphere. When solving addition tasks, the coherence asymmetry was increased in left hemisphere between frontal, parietal and temporal areas in delta-theta-band as well as between frontal and parietal regions in alpha-band. The neurophysiological mechanisms of complex addition and multiplication arithmetic task solving is discussed.

Influence of simple verbal and non-verbal stimuli on brain electrical activity.

In this study, the influence of analysis stimulus content on the reaction time (RT) and parameters of the brain activity was investigated. Thirty healthy right-handed volunteers (mean age 24 years) participated in the study. The dynamics of RT, characteristics of electroencephalogram (EEG) and event-related potentials (ERP) components during perception of digits and non-verbal stimuli were analyzed. The specificity of RT's asymmetry in simple and complex visual-motor reactions depended on stimulus type was revealed. The similarity of early ERP components (peak latency of 100-200 ms) for both stimuli types in simple and complex visual-motor reaction was shown. We also described the formation of specific ERP configuration for digits differentiation such as a left-sided asymmetry of component N200, and increase of peak latency of the late negative component with their extension to the parietal region.