The posterior parietal cortex (PPC) is a central hub for the primate forebrain networks that control skilled manual behavior, including tool use. Here, we quantified and compared the sources of thalamic input to electrophysiologically-identified hand/forearm-related regions of several PPC areas, namely areas 5v, AIP, PFG, and PF, of the capuchin monkey (Sapajus sp). We found that these areas receive most of their thalamic connections from the Anterior Pulvinar (PuA), Lateral Posterior (LP) and Medial Pulvinar (PuM) nuclei. Each PPC area receives a specific combination of projections from these nuclei, and fewer additional projections from other nuclei. Moreover, retrograde labeling of the cells innervating different PPC areas revealed substantial intermingling of these cells within the thalamus. Differences in thalamic input may contribute to the different functional properties displayed by the PPC areas. Furthermore, the observed innervation of functionally-related PPC domains from partly intermingled thalamic cell populations accords with the notion that higher-order thalamic inputs may dynamically regulate functional connectivity between cortical areas.

中文翻译：

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丘脑向后壁皮质区域的丘脑输入，涉及卷尾猴的熟练前肢运动和工具使用。

顶叶后皮质（PPC）是灵长类前脑网络的中央枢纽，控制熟练的人工行为，包括使用工具。在这里，我们量化并比较了丘脑猴的几个丘脑猴（Sapajus sp）的几个PPC区域（即5v，AIP，PFG和PF区域）的电生理识别手/前臂相关区域的丘脑输入源。我们发现这些区域大部分来自前丘脑（PuA），外侧后牙（LP）和内侧丘脑（PuM）核的丘脑连接。每个PPC区域从这些原子核接收特定的投影组合，而从其他原子核接收的附加投影则更少。此外，逆行标记的神经支配不同的PPC区域揭示了这些细胞在丘脑内的大量混杂。丘脑输入的差异可能会导致PPC区域显示的功能特性不同。此外，从部分混合的丘脑细胞群中观察到的功能相关的PPC域的神经支配符合这样的观念，即高阶丘脑输入可以动态调节皮质区域之间的功能连接。