Detection of motor planning and suppression with the help of electroencephalography

The aim of this study was to investigate, if it is possible to detect brain activity related to motor planning and suppression with the help of Electroencephalograms (EEG), the ultimate goal being, to simultaneously measure EEG and functional magnetic resonance imaging (fMRI). Towards this end we engaged a delayed response task from an earlier fMRI study, thereby ensuring, as a first step, that the results of both EEG and fMRI would be directly comparable. Motor preparatory signals were recorded in seven subjects using 10-20-system fMRI compatible EEG equipment. The a and p frequency bands of the EEG recordings were analyzed first individually and then on the group level. Using a non-parametric statistical test, significant clusters relating to motor planning were mainly found over the motor and posterior parietal cortex of the right hemisphere. Activity corresponding with motor suppression was exhibited over the parietal and occipital cortex, located mainly medially for the lower p band (13-20Hz) and extended towards the right hemisphere for the a band. Active regions corresponded well to the ones revealed in our previous fMRI study. Simultaneous EEG and fMRI of this task in the future could thus provide us with combined information on timing (EEG), locality (fMRI) and activity characteristics (both) during motor planning and suppression.