Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
Division of Neuroscience, Oregon National Primate Research Center, OHSU, Beaverton, OR 97006, USA.
Cereb Cortex. 2023 May 24;33(11):7258-7275. doi: 10.1093/cercor/bhad036.
The posterior parietal cortex (PPC) of squirrel monkeys contains subregions where long trains of intracortical microstimulation evoke complex, behaviorally meaningful movements. Recently, we showed that such stimulation of a part of the PPC in the caudal lateral sulcus (LS) elicits eye movements in these monkeys. Here, we studied the functional and anatomical connections of this oculomotor region we call parietal eye field (PEF) with frontal eye field (FEF) and other cortical regions in 2 squirrel monkeys. We demonstrated these connections with intrinsic optical imaging and injections of anatomical tracers. Optical imaging of frontal cortex during stimulation of the PEF evoked focal functional activation within FEF. Tracing studies confirmed the functional PEF-FEF connections. Moreover, tracer injections revealed PEF connections with other PPC regions on the dorsolateral and medial brain surface, cortex in the caudal LS, and visual and auditory cortical association areas. Subcortical projections of PEF were primarily with superior colliculus, and pontine nuclei as well as nuclei of the dorsal posterior thalamus and caudate. These findings suggest that PEF in squirrel monkey is homologous to lateral intraparietal (LIP) area of macaque, supporting the notion that these brain circuits are organized similarly to mediate ethologically relevant oculomotor behaviors.
松鼠猴的顶后皮质（PPC）包含一些亚区，在这些亚区中，长串的皮层内微刺激会引发复杂的、具有行为意义的运动。最近，我们发现刺激侧裂后部的一部分 PPC 会引起这些猴子的眼球运动。在这里，我们研究了这个我们称之为顶眼区（PEF）与额眼区（FEF）和其他皮质区域的功能和解剖连接，在 2 只松鼠猴中进行了研究。我们通过内在光学成像和解剖示踪剂注射来证明这些连接。在刺激顶眼区时对额皮质进行光学成像，会在额眼区引发焦点功能激活。追踪研究证实了顶眼区与额眼区的功能连接。此外，示踪剂注射显示顶眼区与背外侧和内侧脑表面的其他 PPC 区域、尾侧 LS 中的皮质以及视觉和听觉皮质联合区之间存在连接。顶眼区的皮质下投射主要与上丘、脑桥核以及背侧丘脑后核和尾状核有关。这些发现表明，松鼠猴的顶眼区与猕猴的外侧顶内区（LIP）同源，支持这些大脑回路以类似的方式组织来介导与行为相关的眼球运动行为的观点。
