pro-saccade trials. While Fig. 5C and E represents the increase in neck EMG above baseline, the absolute level of evoked neck EMG was also greater on anti-saccade vs. pro-saccade trials (data not shown, but note how the divergence in Fig. 5C for the last two stimulation intervals exceeds the divergence in baseline activity). This observation means that ICMS-SEF is not simply driving the muscles to the maximal level of recruitment. Further, note how these EMG increases are much smaller in magnitude than the visual response on neck muscles shown in Fig. 4C, which itself tends to be far less than the DAPT mw neck muscle recruitment that accompanies saccade generation,

even when head-restrained (Corneil et al., 2004, 2008; Chapman & Corneil, 2011). Finally, we analysed the neck EMG responses evoked by ICMS-SEF delivered in the post-cue interval. HDAC cancer These data are further segregated by saccade direction relative to the side of the stimulating electrode, as the evoked neck EMG interacts with the visual response on neck muscles for later stimulation times. Accordingly, we describe the effects of ICMS-SEF at each of the four post-cue intervals in sequence, in reference to the data shown in Fig. 6. Again, Fig. 6 shows data from the representative site (Fig. 6A), and across our sample (Fig. 6B–E). As mentioned above, the response evoked

by SEF stimulation at the earliest post-cue interval (i.e. 10 ms after cue presentation) precedes the visual response Staurosporine on neck muscles. Accordingly, the increase in EMG activity above baseline depended only on task (being greater on anti-saccades), but not on saccade direction (leftmost traces in Fig. 6A; leftmost series of datapoints, Fig. 6C). In contrast, the response evoked by SEF stimulation delivered slightly later (i.e. 43 ms after cue presentation) displayed a marked dependency with both task and saccade direction. At this interval, ICMS-SEF before ipsilaterally directed anti-saccades (dashed lines around empty traces in Fig. 6A; dashed line connecting circles in Fig. 6C) evoked the largest

response, followed by stimulation preceding contralaterally directed pro-saccades (solid traces in Fig. 6A; solid line connecting squares in Fig. 6C). Note that both such trials feature cue presentation on the side of the muscle (i.e. contralateral to the side of the stimulating electrode), and hence the evoked response is interacting with the ongoing visual response on neck muscles. Even here, it is clear that the stimulation-evoked effect is greater on anti- vs. pro-saccades, and the consistency of this effect is demonstrated by the shifts in the frequency histograms in Fig. 6E, which represent the difference in saccade direction for either pro- (upward histrograms) or anti-saccades (downward histograms).