Department of Psychology, New York University, New York, NY 10003, USA.
Department of Psychology, New York University, New York, NY 10003, USA; Center for Neural Science, New York University, New York, NY 10003, USA.
Curr Biol. 2020 Oct 19;30(20):4078-4084.e3. doi: 10.1016/j.cub.2020.07.068. Epub 2020 Aug 13.
Orienting covert exogenous (involuntary) attention to a target location improves performance in many visual tasks [1, 2]. It is unknown whether early visual cortical areas are necessary for this improvement. To establish a causal link between these areas and attentional modulations, we used transcranial magnetic stimulation (TMS) to briefly alter cortical excitability and determine whether early visual areas mediate the effect of exogenous attention on performance. Observers performed an orientation discrimination task. After a peripheral valid, neutral, or invalid cue, two cortically magnified gratings were presented, one in the stimulated region and the other in the symmetric region in the opposite hemifield. Observers received two successive TMS pulses around their occipital pole while the stimuli were presented. Shortly after, a response cue indicated the grating whose orientation observers had to discriminate. The response cue either matched-target stimulated-or did not match-distractor stimulated-the stimulated side. Grating contrast was varied to measure contrast response functions (CRF) for all combinations of attention and TMS conditions. When the distractor was stimulated, exogenous attention yielded response gain-performance benefits in the valid-cue condition and costs in the invalid-cue condition compared with the neutral condition at the high contrast levels. Crucially, when the target was stimulated, this response gain was eliminated. Therefore, TMS extinguished the effect of exogenous attention. These results establish a causal link between early visual areas and the modulatory effect of exogenous attention on performance.
引导隐蔽的外源性（无意识）注意到目标位置可以提高许多视觉任务的表现[1,2]。目前尚不清楚早期视觉皮层区域是否对此改善有必要。为了在这些区域和注意力调节之间建立因果联系，我们使用经颅磁刺激（TMS）短暂改变皮质兴奋性，并确定早期视觉区域是否介导外源性注意对性能的影响。观察者执行了方向辨别任务。在周边有效、中性或无效提示后，呈现两个皮质放大的光栅，一个在刺激区域，另一个在对侧视野中的对称区域。当刺激呈现时，观察者在枕骨极周围接受两个连续的 TMS 脉冲。之后不久，响应提示指示观察者必须辨别其方向的光栅。响应提示与刺激侧匹配-目标刺激或不匹配-分心刺激。改变光栅对比度以测量所有注意力和 TMS 条件组合的对比度响应函数（CRF）。当分心物被刺激时，与中性条件相比，在外源注意的有效提示条件下，响应增益表现出收益，而在无效提示条件下则会出现成本，在高对比度水平下。至关重要的是，当目标被刺激时，这种响应增益被消除了。因此，TMS 消除了外源性注意的影响。这些结果在早期视觉区域和外源性注意对性能的调节作用之间建立了因果联系。
