Cognitive, Linguistic & Psychological Sciences, Brown University, Providence, RI 02912, USA.
Department of Neuroscience, Brown University, Providence, RI 02912, USA.
Cereb Cortex. 2022 Apr 20;32(9):1787-1803. doi: 10.1093/cercor/bhab308.
The posterior parietal cortex (PPC) is important for visuospatial attention. The primate PPC shows functional differentiation such that dorsal areas are implicated in top-down, controlled attention, and ventral areas are implicated in bottom-up, stimulus-driven attention. Whether the rat PPC also shows such functional differentiation is unknown. Here, we address this open question using functional neuroanatomy and in vivo electrophysiology. Using conventional tract-tracing methods, we examined connectivity with other structures implicated in visuospatial attention including the lateral posterior nucleus of the thalamus (LPn) and the postrhinal cortex (POR). We showed that the LPn projects to the entire PPC, preferentially targeting more ventral areas. All parts of the PPC and POR are reciprocally connected with the strongest connections evident between ventral PPC and caudal POR. Next, we simultaneously recorded neuronal activity in dorsal and ventral PPC as rats performed a visuospatial attention (VSA ) task that engages in both bottom-up and top-down attention. Previously, we provided evidence that the dorsal PPC is engaged in multiple cognitive process including controlled attention (Yang et al. 2017). Here, we further showed that ventral PPC cells respond to stimulus onset more rapidly than dorsal PPC cells, providing evidence for a role in stimulus-driven, bottom-up attention.
顶后皮质（PPC）对于视空间注意非常重要。灵长类动物的 PPC 表现出功能分化，即背侧区域与自上而下的控制注意有关，而腹侧区域与自下而上的刺激驱动注意有关。大鼠的 PPC 是否也表现出这种功能分化尚不清楚。在这里，我们使用功能神经解剖学和活体电生理学来解决这个悬而未决的问题。使用传统的追踪方法，我们研究了与其他涉及视空间注意的结构的连接，包括外侧丘脑后核（LPn）和后梨状皮质（POR）。我们表明，LPn 投射到整个 PPC，优先靶向更腹侧的区域。PPC 和 POR 的所有部分都与 LPn 和 POR 进行相互连接，其中腹侧 PPC 和尾部 POR 之间的连接最强。接下来，当大鼠执行涉及自上而下和自下而上注意力的视空间注意力（VSA）任务时，我们同时记录了背侧和腹侧 PPC 中的神经元活动。此前，我们提供的证据表明，背侧 PPC 参与了包括控制注意力在内的多种认知过程（Yang 等人，2017 年）。在这里，我们进一步表明，腹侧 PPC 细胞比背侧 PPC 细胞对刺激开始的反应更快，这为刺激驱动的自下而上的注意力提供了证据。
