The electrophysiological indicators of fronto-central networks for visual control during goal-directed reaching


In this study the neural correlates of goal-directed reaching were investigated under varying conditions of visual feedback. Recent studies have revealed a negative brain potential occurring over fronto-central regions of the brain following peak velocity of a reaching movement. Specifically, when large errors are encountered, the amplitude of this potential is greater as compared to movements with less error (Torrecillos et al., 2014). While it is suggested that this brain potential is a consequence of error detection (Torrecillos et al., 2014), others have suggested that it may simply reflect the motor output associated with the decelerating limb (Kirsch & Henninghausen, 2010). In order to further investigate what this potential holds we systematically manipulated the availability of visual feedback of the hand and target. Participants performed aiming movements to two target locations, with vision of 1) the hand and target; 2) hand only; 3) target only; 4) without vision of the hand and target. If indeed this brain potential is reflective of visual feedback and error processing, we may expect to see a decrease in its amplitude when visual feedback is unavailable as individuals are unable to assess error with real-time vision. Behavioural results were consistent with previous research, notably a decrease in trajectory amendments associated with online control for conditions where vision of the hand is withheld (e.g., Heath, 2005). For the electrophysiological results, we also found a modulation of the negative brain potential over frontal and central electrodes, associated with the variations in visual feedback and target location. Furthermore, wavelet analyses revealed a corresponding modulation in the activity in the theta frequency band with respect to visual feedback availability. In all, these findings support the idea that the fronto-central neural structures are involved with the real-time assessment of reach errors.

Acknowledgments: NSERC