Brown L L, Smith D M, Goldbloom L M
Department of Neurology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
J Comp Neurol. 1998 Mar 23;392(4):468-88.
The neuroanatomic organizing principles underlying integrative functions in the striatum are only partially understood. Within the three major subdivisions of the striatum-sensorimotor, associative, and limbic--longitudinal zones of axonal plexuses from the cerebral cortex end in bands and clusters that innervate cell groups. To identify organizing principles of the corticostriate bands and clusters, we localized somatosensory cortical cells receptive to light touch on the hindlimb, forelimb, or vibrissae by extracellular recording, and we labeled their projections by iontophoretic application of dextran anterograde tracers. The results show that cortical cells in columnar groups project to the striatum in the form of successive strips, or laminae, that parallel the curve of the external capsule. The vibrissae somatosensory cortex projects to the most lateral lamina. Just medial to the vibrissae projection, the major axonal arborizations arising from hindlimb and forelimb somatosensory cortex are organized within a common lamina, where they interdigitate and overlap as well as remain separate. In addition, the hindlimb and forelimb cortex send small projections to the vibrissae lamina, and vice versa, forming broken, radially oriented lines of points across the laminar strips. The major somatosensory projections are in the dorsolateral, calbindin-poor sensorimotor striatum, whereas the radially oriented projection points extend into the medial, calbindin-rich associative striatum. Extending previous studies of corticostriate projections, this report shows a grid translation of columnar somatosensory cortical inputs into striatum and a detailed map for the rat sensorimotor zone. The lattice-like grid is a novel functional/neuroanatomic organization that is ideal for distributing, combining, and integrating information for sensorimotor and cognitive processing.
纹状体整合功能背后的神经解剖学组织原则仅得到部分理解。在纹状体的三个主要亚区——感觉运动区、联合区和边缘区——来自大脑皮质的轴突丛纵向区域终止于支配细胞群的条带和簇中。为了确定皮质纹状体条带和簇的组织原则，我们通过细胞外记录定位了对后肢、前肢或触须轻触有反应的体感皮质细胞，并通过离子电渗法应用葡聚糖顺行示踪剂标记它们的投射。结果表明，柱状组中的皮质细胞以连续条带或层的形式投射到纹状体，这些条带或层与外囊的曲线平行。触须体感皮质投射到最外侧的层。就在触须投射的内侧，来自后肢和前肢体感皮质的主要轴突分支在一个共同的层内组织，它们在那里相互交错、重叠并保持分开。此外，后肢和前肢皮质向触须层发送小的投射，反之亦然，在层状条带上形成断裂的、径向排列的点线。主要的体感投射位于背外侧、钙结合蛋白含量低的感觉运动纹状体，而径向排列的投射点延伸到内侧、钙结合蛋白含量高的联合纹状体。扩展先前对皮质纹状体投射研究，本报告显示了柱状体感皮质输入到纹状体的网格转换以及大鼠感觉运动区的详细图谱。这种格子状网格是一种新型的功能/神经解剖学组织，非常适合为感觉运动和认知处理分配、组合和整合信息。
