The temporal evolution of oscillatory activity predicts performance in a 1 choice - reaction time reaching task 2 3

25 In this study, we characterized the patterns and timing of cortical activation of 26 visually-guided movements in a task with critical temporal demands. In particular, we 27 investigated the neural correlates of motor planning and on-line adjustments of reaching 28 movements in a choice-reaction time task. High-density EEG (256 electrodes) was 29 recorded in 13 subjects performing reaching movements. The topography of the 30 movement-related spectral perturbation was established across five 250-ms temporal 31 windows (from pre-stimulus to post-movement) and five frequency bands (from theta to 32 beta). Nine regions of interest were then identified on the scalp and their activity was 33 correlated with specific behavioral outcomes reflecting motor planning and on-line 34 adjustments. Phase coherence analysis was performed between selected sites. We found 35 that motor planning and on-line adjustments share similar topography in a fronto-parietal 36 network, involving mostly low frequency bands. In addition, activities in the high and 37 low frequency ranges have differential function in the modulation of attention, with the 38 former reflecting the pre-stimulus, top-down processes needed to promote timely 39 responses, and the latter the planning and control of sensory-motor processes. 40 41