The proposed neural mechanisms supporting blindsight, the above-chance performance of cortically blind patients on forcedchoice visual discrimination tasks, are controversial. In this article, we show that although subjects were unable to perceive foveally presented visual stimuli when transcranial magnetic stimulation over the visual cortex induced a scotoma, responses nonetheless were delayed significantly by these unconscious distractors in a directed saccade but not in an indirect manual response task. These results suggest that the superior colliculus, which is involved with sensory encoding as well as with the generation of saccadic eye movements, is mediating the unconscious processing of the transcranial magnetic stimulation-suppressed distractors and implicate a role of the retinotectal pathway in many blindsight phenomena.saccades ͉ perception ͉ consciousness ͉ visual cortex ͉ human

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Inhibition of return (IOR) is a bias against reorienting attention to a previously cued location. In this study, using single-pulse transcranial magnetic stimulation (TMS), we show that the human frontal eye fields (FEF) play a crucial role in the generation of IOR. When TMS was applied over the right FEF at a time interval after a visual cue but shortly before the target, IOR was modulated in the hemifield ipsilateral to the TMS such that responses to a previously cued target were no longer slower than responses to uncued targets. Control TMS over the superior parietal lobule, as well as TMS of the FEF shortly after the cue but well before the target, had no influence on IOR. We further show that the FEF is involved with visual selection as responses to targets appearing contralateral to the TMS of the FEF, but not the control site, were delayed. These results suggest that the FEF produces IOR by biasing attention and eye movements away from a previously attended location and facilitating target detection at novel locations.

The stop-signal paradigm has been widely adopted as a way to parametrically quantify the response inhibition process. To evaluate inhibitory function in realistic environmental settings, the current study compared stop-signal responses in two different scenarios: one uses simple visual symbols as go and stop signals, and the other translates the typical design into a battlefield scenario (BFS) where a sniper-scope view was the background, a terrorist image was the go signal, a hostage image was the stop signal, and the task instructions were to shoot at terrorists only when hostages were not present but to refrain from shooting if hostages appeared. The BFS created a threatening environment and allowed the evaluation of how participants’ inhibitory control manifest in this realistic stop-signal task. In order to investigate the participants’ brain activities with both high spatial and temporal resolution, simultaneous functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) recordings were acquired. The results demonstrated that both scenarios induced increased activity in the right inferior frontal gyrus (rIFG) and presupplementary motor area (preSMA), which have been linked to response inhibition. Notably, in right temporoparietal junction (rTPJ) we found both higher blood-oxygen-level dependent (BOLD) activation and synchronization of theta-alpha activities (4–12 Hz) in the BFS than in the traditional scenario after the stop signal. The higher activation of rTPJ in the BFS may be related to morality judgments or attentional reorienting. These results provided new insights into the complex brain networks involved in inhibitory control within naturalistic environments.