Similarly, in Fig. 9D (middle) for monkey J, it can be seen that microsaccades with similar latencies after cue onset were also biased towards the foil location despite the inactivation at that location. Thus, consistent with the lack of reduction in microsaccade rate in both monkeys (Figs 3-5), these
results indicate that peripheral SC inactivation disrupted cue-induced microsaccade directions, but not necessarily the motor ability to generate microsaccades towards the affected region of visual space. The above results in both monkeys may therefore be summarised as follows. In both monkeys, SC inactivation caused a net bias of microsaccade directions away from the visual quadrant affected by the inactivation. In monkey M, when the cue was placed in the inactivated region, this bias away from the affected region acted to eliminate the original pre-injection bias towards the cue (Fig. 8B); when the foil was placed in the Smoothened antagonist affected region Gemcitabine instead, this same bias away from the affected region acted to maintain the original pre-injection bias away from the foil (and towards the cue) (Fig. 8D). For monkey J, placing the cue in the affected region during inactivation caused a bias away from the cued location and towards the irrelevant ‘neither’
locations (Fig. 9B). When the foil was in the affected region, there was also a bias away from the foil location (Fig. 9D, middle, red arrow), and again towards the ‘neither’ locations. In both monkeys, muscimol-induced biases away from the inactivated region emerged ~110 ms earlier than the normal latencies of directional microsaccade biases that we observed without SC inactivation. The attention task required the monkeys to sustain attention http://www.selleck.co.jp/products/Verteporfin(Visudyne).html for a prolonged interval prior to the presentation of the pulse of coherent motion. The normal behavioral patterns
of errors without SC inactivation reveal that the monkeys paid particular attention to the cued and foil locations and less attention to the remaining two quadrants prior to the onset of the motion pulse (Lovejoy & Krauzlis, 2010). By analysing microsaccade directions just around the onset of the motion pulse, we were able to document the potential influence of such sustained covert attentional allocation on microsaccade directions. Figure 10A shows the results of this analysis in the pre-injection condition before inactivation. In this case, we analysed only microsaccades occurring within 70 ms from the onset of the motion pulse. Because this analysis interval was short and synchronised to trial end, it all but eliminated the inclusion of any cue-induced or stimulus-induced microsaccades like those described in earlier figures of this article. Thus, the microsaccades in this analysis are not the same as those presented in Figs 8 and 9. Moreover, these microsaccades were not affected by the motion pulse itself, because they occurred too early (relative to motion pulse onset) for any potential influence of visual motion to affect their motor generation.