Miniussi C, Wilding E L, Coull J T, Nobre A C
Department of Experimental Psychology, University of Oxford, Oxford UK.
Brain. 1999 Aug;122 ( Pt 8):1507-18. doi: 10.1093/brain/122.8.1507.
With the aim of casting light on the neural mechanisms that support our ability to modulate visual attention over time, we recorded event-related potentials (ERPs) while normal human subjects performed a target detection task with temporal contingencies between cue and target stimuli. The task used two central cues, which predicted (80% validity) when a subsequent target would occur (either 600 or 1400 ms after cue onset). Unlike previous tasks of attentional orienting, there was no spatial information provided and all stimuli were presented foveally. Reaction times and ERPs linked to targets presented at the shorter interval showed significant effects linked to attentional orienting. Reaction times were faster when the cues correctly predicted the cue-target interval, suggesting the ability of the brain to use information about time to deploy attentional resources. ERPs differed according to the predicted time interval. In particular, the P300 amplitude and latency were enhanced when the cue predicted the cue-target interval accurately. The ERPs elicited by the cues also differed according to the time interval that they predicted. Differences were observed in potentials linked to motor preparation and expectancies. The results reveal dynamic neural activity involved in orienting attention to time intervals, as well as the consequent modulation of target-related neural activity resulting from differing temporal expectations.
为了阐明支持我们随时间调节视觉注意力能力的神经机制，我们记录了正常人类受试者在执行线索与目标刺激之间存在时间关联的目标检测任务时的事件相关电位（ERP）。该任务使用了两个中央线索，它们预测（80%的有效性）后续目标何时会出现（线索开始后600或1400毫秒）。与以往的注意力定向任务不同，该任务没有提供空间信息，所有刺激都呈现在中央凹。与较短间隔呈现的目标相关的反应时间和ERP显示出与注意力定向相关的显著影响。当线索正确预测线索 - 目标间隔时，反应时间更快，这表明大脑能够利用时间信息来分配注意力资源。ERP根据预测的时间间隔而有所不同。特别是，当线索准确预测线索 - 目标间隔时，P300的幅度和潜伏期会增强。线索引发的ERP也根据它们预测的时间间隔而有所不同。在与运动准备和预期相关的电位中观察到了差异。结果揭示了参与将注意力定向到时间间隔的动态神经活动，以及由不同时间预期导致的对目标相关神经活动的相应调节。
