The event related potential technique and microstate analysis of memory guided and visually guided movements.
26.506, Saturday, 17-May, 2:45 pm - 6:45 pm, Pavilion
Darian Cheng1, Krista Fjeld1, Gordon Binsted1; 1University of British Columbia
While behavioral protocols have primarily been used to examine the use of memory in human movement (Elliott & Madalena, 1987; Westwood, Heath & Roy, 2003), more recent examinations have involved more imaging techniques to determine the underlying brain processes that facilitate this function (Krigolson et al., 2011). This study examines the neural correlates associated with memory guided and visually guided reaching movements using electroencephalography (EEG). Participants performed manual aiming movements to targets under varying visual feedback (full-vision & no-vision) and delay (2 or 5 s) conditions. In experiment 1, conditions were randomized across trials while in experiment 2 conditions were blocked. Using the event related potential (ERP) technique we observed the visually evoked potentials (VEPs) associated with the preview of the target as well as movement related potentials associated with movement execution. The behavioral findings from the study replicated the typical advantage of having visual feedback i.e., greater accuracy and precision with vision. Additionally, the electrophysiological data revealed differences in brain potentials across vision conditions during target encoding and movement execution within the blocked protocol. Notably, brain potentials over parietal electrodes were suppressed in memory guided reaches as compared to visually guided reaches. Moreover, a longer delay period in no-vision revealed greater suppression of brain potentials. A micro-state analysis (i.e., Cartool software) involving the full electrode montage was used to examine the clustering of activity across the scalp over time. The results of this analysis showed differences in microstate duration across vision conditions that not only reinforce the basic ERP findings but also providing greater clarity on the potential underlying neural processes sub-serving manual aiming.