Coherence of EEG frequency components during manual movements executed by the subdominant hand in women

Abstract

The academic community is paying more and more attention to the question of the individual characteristics of the brain processes which ensure the manual motor programming of movements performed not only by the leading, but also by the subdominant hand. Researchers do not exclude the existence of the particular parameters of the human brain correlating with manual motor activities. This study involved 136 women at the age of 19–21 years. The testees were divided into two groups according to high and low values of the EEG modal α-frequency determined individually and in a motionless state. We evaluated the coherence status of the EEG frequency components in the motionless state and during movements performed by fingers of the subdominant (left) hand in response to rhythmic sound signals. The testing stages involved the sequential execution of motor tasks including clamping and unclamping performed by the fingers of the subdominant hand (such as grasping movements) without effort. The testees also performed fingering (a manual response to each stimulus) at in different times and not by all the fingers of the hand simultaneously, but separately, one by one, in a given sequence). Clamping and unclamping was executed by the fingers subject to power loading the (additional load on the fingers being 10H). Execution of manual movements by means of the subdominant hand in response to the sensory signals was accompanied by an increase in coherence in the EEG frequency components, especially in the frontal, temporal, and parietal cortexes of the central areas. Women with a low individual α-rate of such a regularity had significantly increased scores at the high (α3-, β-) frequencies of the EEG spectrum. At the same time, women in both groups mainly showed a decrease in the coherence coefficients of θ-, α1- and α3-activity in the frontal cortex leads in terms of the execution of the sequential finger movements and movements under power loading. The analysis of differences proved that women with a low IαF had relatively higher coherence of the EEG frequency components in the frontal lobes. However, relatively higher frequency components of EEG coherence in the central, posterior temporal and parietal leads were set in women with high IαF. Changes in cortical activity were established during different movements performed by fingers of the subdominant hand, namely, grasping movements of common occurrence, successive movements and movements under power loading. They differ from each other in their low specificity. Thus, the factor of motor performance of tests by means of the subdominant hand had obviously more decisive importance in the nature of the organization of brain activity than for the actual specifics of manual movements.

Keywords

• individual α-frequency
• successive movements
• power load
• grasping movements