Investigating the EEG Alpha Band during Kinesthetic and Visual Motor Imagery of the Spike Volleyball Movement

Abstract

Motor Imagery (MI) is the mental simulation of motor tasks and its execution may recover a motor planning in the central nervous system. The purpose of this study was to analyze the changes along trials of Motor Imagery (MI) in Kinesthetic (KMI) and Visual (VMI) modalities. The casuistry initially consisted of 15 right-handed male volleyball athletes (AG) and 18 non-athletes (NAG). By previously applying MIQ-R, 3 subjects from NAG were dismissed of the study due to their low questionnaire score. Both groups performed 30 trials of KMI and VMI of spike volleyball movement, intermixed with mental countdown (REF). The t-test (α = 0.05) resulted in similar MIQ-R mean scores for both groups, although AG demonstrated greater facility to imagine the volleyball task than NAG. Each EEG free-artifact signal was subdivided in three sequences (S1, S2 and S3) with 8 epochs each. Wilcoxon paired tests (α = 0.05) of the EEG power spectrum in the vicinity of alpha peak (ABP) suggests habituation during initial trial (S1) mainly for athletes. The comparisons between REF and KMI using the spectral F-test (SFT with α = 0.05) indicates the left occipital (athletes) and parietal (non-athletes) sites as those in which SFT> SFT_crit. Based on such results, one can conclude that the KMI modality promotes more cortical changes than VMI, particularly for non-athletes. These findings suggest a different learning process of MI execution of repetitive sequences, related to previous knowledge of the real task.