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Abstract：
This work challenges the widely accepted model of sensory gating as a preattention inhibitory process by investigating whether attention directed at the second tone (S2) within a paired-click paradigm could affect gating at the cortical level. We utilized magnetoencephalography, magnetic resonance imaging and spatio-temporal source localization to compare the cortical dynamics underlying gating responses across two conditions (passive and attention) in 19 healthy subjects. Source localization results reaffirmed the existence of a fast processing pathway between the prefrontal cortex (PFC) and bilateral superior temporal gyri (STG) that underlies the auditory gating process. STG source dynamics comprised two gating sub-components, Mb1 and Mb2, both of which showed significant gating suppression (>51%). The attention directed to the S2 tone changed the gating network topology by switching the prefrontal generator from a dorsolateral location, which was active in the passive condition (18/19), to a medial location, active in the attention condition (19/19). Enhanced responses to the attended stimulus caused a significant reduction in gating suppression in both STG gating components (>50%). Our results demonstrate that attention not only modulates sensory gating dynamics, but also exerts topological rerouting of information processing within the PFC. The present data, suggesting that the cortical levels of early sensory processing are subject to top-down influences, change the current view of gating as a purely automatic bottom-up process.
摘要：
这项工作通过研究成对点击范式中针对第二音调（S2）的注意力是否会影响皮层水平的门控，挑战了被广泛接受的感觉门控模型作为注意力前抑制过程。我们利用了脑磁图，磁共振成像和时空源定位，以比较19名健康受试者在两种条件（被动和注意力）下的门控反应的皮层动力学。源定位结果重申了前额叶皮层（PFC）和双侧颞上回（STG）之间存在快速处理途径，这是听觉门控过程的基础。STG源动力学包括两个门控子组件，Mb1和Mb2,两者均显示出显著的门控抑制(>51%)。对S2音调的关注通过从背侧位置切换前额叶发生器来改变门控网络拓扑，在被动状态下是主动的(18/19)，到中间位置，在注意力状态下活跃(19/19)。对伴随刺激的增强反应导致两种STG门控成分的门控抑制显着降低（>50％）。我们的结果表明，注意力不仅调节感觉门控动力学，而且还在PFC内对信息处理进行拓扑重新路由。目前的数据,这表明早期感觉处理的皮层水平受到自上而下的影响，将门控的当前视图更改为纯自动自下而上的过程。
