, 1998). The study by Terao and colleagues also delivered TMS over the

SEF in humans, and surprisingly did not observe any significant influence on anti-saccade behaviour. Whether the difference between our results and those in the human TMS literature arise from differences in the species, form of stimulation or exact behavioral paradigm is unclear. TMS can be delivered to monkeys performing oculomotor tasks (Gerits et al., 2011; Valero-Cabre et al., 2012), and hence it should be possible to have direct comparison Atezolizumab manufacturer of different forms of stimulation on anti-saccade behavior in the same species. Returning to the monkey, our behavioral results resemble those produced following pharmacological inactivation of the ventroanterior and ventrolateral nuclei of the thalamus during an intermixed pro-/anti-saccade task (Kunimatsu & Tanaka, 2010). Neural activity within these nuclei is consistently greater on anti- than on pro-saccade trials, which resembles that reported in the SEF but differs from other frontal and brainstem structures (reviewed by Johnston & Everling, 2008). Based on this similarity, Kunimatsu

& Tanaka (2010) hypothesized that thalamocortical pathways play an essential role in anti-saccade control. Our results are consistent with this view if one assumes that short-duration ICMS-SEF transiently disrupts processing in this pathway. We are not suggesting that ICMS-SEF selectively disrupts

cortico-thalamic processing Lumacaftor mw without influencing other pathways, but speculate that it is this pathway that is primarily responsible for the surprisingly bilateral influences of ICMS-SEF on anti-saccade behavior. The SEF is also richly interconnected with numerous other cortical and subcortical oculomotor structures (e.g. the FEF, ACC, PFC, the superior colliculus (SC), and oculomotor brainstem; reviewed by Johnston & Everling, 2011), and the effect of ICMS-SEF on these pathways may explain some of the lateralized tendencies in our behavioral results. Up to now, we have focused on the impact of ICMS-SEF on anti-saccade behavior, which we speculate may arise from an influence on signaling within cortico-thalamic networks. The second major series of results is the augmented others recruitment of a contralateral head-turning synergy that accompanies the selective disruption of anti-saccade behavior. During the fixation interval, the magnitude of contralateral muscle recruitment gradually diverged to become larger prior to anti- vs. pro-saccades. Critically, the magnitude of the evoked response did not simply mirror neck muscle recruitment preceding ICMS-SEF. Hence, a straightforward gain of the evoked response that is proportional to motoneuron excitability cannot explain the larger evoked responses as subjects prepare to generate anti-saccades.