Thus, cue onset introduced a large bias in microsaccade direction during this session, as documented previously (Hafed et al., 2011). During SC inactivation, and with the cued location in the same, but now affected, region (Fig. 6B), this pattern was completely reversed – the initial bias

of microsaccade directions after cue onset was now towards the foil and not the cue (red arrows). This finding demonstrates that, even though inactivation of the peripheral SC in this sample experiment did not reduce overall www.selleckchem.com/products/Erlotinib-Hydrochloride.html microsaccade rate or change the overall temporal pattern of microsaccade generation (Fig. 3), it did cause a large redistribution in the directions of microsaccades (Fig. 6B). When the stimulus configuration was altered such that the foil was placed in the affected region of this sample SC inactivation instead of the cue, this large redistribution of microsaccade directions caused by inactivation did not occur (compare Fig. 6C and 6D), because the cue in the unaffected region of space was as effective in inducing microsaccades toward

its location (Fig. 6D) as it was before the inactivation (Fig. 6C). The results from this sample session therefore indicate that cue-induced changes in microsaccade directions were mediated by cue-related activity in the peripheral SC; elimination of such activity through muscimol-induced Ureohydrolase inactivation altered the influence of the peripheral spatial cue on microsaccade directions. We Estrogen antagonist next confirmed that this effect was not a mechanical effect resulting from fluid injection into the neural tissue by repeating exactly the same analysis but for our saline control injection of Fig. 4. The results were very different from those in Fig. 6, because the saline injection did not cause the massive reversal

of microsaccade directions seen above with muscimol. This result is illustrated in Fig. 7, which is presented in a format identical to that of Fig. 6. Thus, the results of the two sample sessions of Figs 6 and 7 combined suggest that muscimol inactivation of the peripheral SC in our task caused a significant alteration in cue-induced microsaccade directions. The effect of peripheral SC inactivation on cue-induced changes in microsaccade directions was also observed consistently across sessions from this monkey. Figure 8 shows the results of analysing microsaccade directions before and during SC inactivation for all experimental sessions involving monkey M. This analysis follows the approach from our previous behavioral study of microsaccades during this covert attention task (Hafed et al., 2011). Figure 8A shows the data obtained prior to SC inactivation for monkey M when the cue was placed in the region soon to be affected by SC inactivation. As can be seen, Fig.