Department of Psychology and Center for Cognitive Sciences, University of Minnesota, Minneapolis, MN, USA.
J Neurophysiol. 2012 Dec;108(12):3239-52. doi: 10.1152/jn.00472.2012. Epub 2012 Sep 19.
Temporal selection poses unique challenges to the perceptual system. Selection is needed to protect goal-relevant stimuli from interference from new sensory input. In addition, contextual information that occurs at the same time as goal-relevant stimuli may be critical for learning. Using fMRI, we characterized how visual cortical regions respond to the temporal selection of auditory and visual stimuli. Critically, we focused on brain regions that are not involved in processing the target itself. Participants pressed a button when they heard a prespecified target tone and did not respond to other tones. Although more attention was directed to auditory input when the target tone was selected, activity in primary visual cortex increased more after target tones than after distractor tones. In contrast to spatial attention, this effect was larger in V1 than in V2 and V3. It was present in regions not typically involved in representing the target stimulus. Additional experiments demonstrated that these effects were not due to multimodal processing, rare targets, or motor responses to the targets. Thus temporal selection of behaviorally relevant stimuli enhances, rather than reduces, activity in perceptual regions involved in processing other information.
时间选择对感知系统提出了独特的挑战。选择是必要的，以保护目标相关的刺激免受新的感官输入的干扰。此外，与目标相关的刺激同时发生的上下文信息对于学习可能是至关重要的。使用 fMRI，我们描述了视觉皮层区域如何响应听觉和视觉刺激的时间选择。关键的是，我们专注于不参与处理目标本身的大脑区域。参与者在听到预定的目标音时按下按钮，而不对其他音做出反应。尽管当选择目标音时，更多的注意力被引导到听觉输入，但与分心音相比，目标音之后的初级视觉皮层的活动增加更多。与空间注意力不同，这种效应在 V1 中比在 V2 和 V3 中更大。它存在于通常不参与表示目标刺激的区域。额外的实验表明，这些效应不是由于多模态处理、罕见目标或对目标的运动反应引起的。因此，行为相关刺激的时间选择增强了参与处理其他信息的感知区域的活动，而不是减少了活动。
