Abstract：
The posterior parietal cortex (PPC) integrates multisensory and motor-related information for generating and updating body representations and movement plans. We used retrograde transneuronal transfer of rabies virus combined with a conventional tracer in macaque monkeys to identify direct and disynaptic pathways to the arm-related rostral medial intraparietal area (MIP), the ventral lateral intraparietal area (LIPv), belonging to the parietal eye field, and the pursuit-related lateral subdivision of the medial superior temporal area (MSTl). We found that these areas receive major disynaptic pathways via the thalamus from the nucleus of the optic tract (NOT) and the superior colliculus (SC), mainly ipsilaterally. NOT pathways, targeting MSTl most prominently, serve to process the sensory consequences of slow eye movements for which the NOT is the key sensorimotor interface. They potentially contribute to the directional asymmetry of the pursuit and optokinetic systems. MSTl and LIPv receive feedforward inputs from SC visual layers, which are potential correlates for fast detection of motion, perceptual saccadic suppression and visual spatial attention. MSTl is the target of efference copy pathways from saccade- and head-related compartments of SC motor layers and head-related reticulospinal neurons. They are potential sources of extraretinal signals related to eye and head movement in MSTl visual-tracking neurons. LIPv and rostral MIP receive efference copy pathways from all SC motor layers, providing online estimates of eye, head and arm movements. Our findings have important implications for understanding the role of the PPC in representation updating, internal models for online movement guidance, eye-hand coordination and optic ataxia.
摘要：
后顶叶皮层（PPC）集成了多感官和运动相关信息，用于生成和更新身体表征和运动计划。我们在猕猴中使用狂犬病病毒的逆行跨神经元转移与常规示踪剂相结合，以确定与手臂相关的头颅内侧顶内区域（MIP）的直接和突触途径，腹侧顶内区（LIPv），属于顶叶眼场，以及内侧上颞区（MSTl）的与追求相关的横向细分。我们发现这些区域通过丘脑从视神经束（NOT）和上丘（SC）的核接受主要的突触通路，主要是同侧。不是道路，最突出地瞄准MSTl，用于处理缓慢眼球运动的感官后果，而NOT是关键的感觉运动界面。它们可能导致追踪和光动力学系统的方向不对称。MSTl和LIPv接收来自SC可视层的前馈输入，它们是快速检测运动的潜在关联，知觉扫视抑制和视觉空间注意。MSTl是来自SC运动层和头部相关网状脊髓神经元的扫视和头部相关隔室的有效复制途径的靶标。它们是与MSTl视觉跟踪神经元中的眼睛和头部运动相关的视网膜外信号的潜在来源。LIPv和rostralMIP接收来自所有SC运动层的有效复制途径，提供在线的眼睛估计，头部和手臂的运动。我们的发现对于理解PPC在表示更新中的作用具有重要意义，用于在线运动指导的内部模型，眼手协调和视神经共济失调。
