Identification of time-frequency EEG features modulated by force direction in arm isometric exertions

Electroencephalographic (EEG) activity associated with human motor tasks has been studied in time domain and time-frequency representations. Various classification and decoding techniques have been used to extract movement or motor task parameters from EEG such as direction of an isometrically exerted force. Identification of time and time-frequency regions that contain the highest directional information can considerably enhance the efficiency of decoding and classification algorithms. In this paper we have addressed this issue for directional arm isometric exertions to 4 different directions in horizontal plane. We have used the non-parametric Permutational ANOVA to identify time-frequency regions capturing the highest level of inter-group variance as a measure of directional information. There are information-rich regions in δ, θ, α, and β bands after corresponding visual cues. Parietal regions show higher directional information during planning compared to execution. The results can be used for pattern classification and decoding of motor parameters in Brain-Computer-Interfacing (BCI) and BCI-rehabilitation.