Brett-Green B A, Chen-Bee C H, Frostig R D
Department of Neurobiology and Behavior and the Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California 92697-4550, USA.
J Neurosci. 2001 Dec 15;21(24):9944-54. doi: 10.1523/JNEUROSCI.21-24-09944.2001.
The anatomical representations of the large facial whiskers, termed barrels, are topographically organized and highly segregated in the posteromedial barrel subfield (PMBSF) of rat layer IV primary somatosensory cortex. Although the functional representations of single whiskers are aligned with their appropriate barrels, their areal extents are rather large, spreading outward from the appropriate barrel along the tangential plane and thereby spanning multiple neighboring and non-neighboring barrels and septal regions. To date, single-whisker functional representations have been characterized primarily for whiskers whose corresponding barrels are located centrally within the PMBSF (central whiskers). Using intrinsic signal imaging verified with post-imaging single-unit recording, we demonstrate that border whiskers, whose barrels are located at the borders of the PMBSF, also evoke large activity areas that are similar in size to those of central whiskers but spread beyond the PMBSF and sometimes beyond primary somatosensory cortex into the neighboring dysgranular zones. This study indicates that the large functional representation of a single whisker is a basic functional feature of the rat whisker-to-barrel system and, combined with results from other studies, suggest that a large functional representation of a small, point-like area on the sensory epithelium may be a functional feature of primary sensory cortex in general.
大鼠初级体感皮层IV层的后内侧桶状亚区（PMBSF）中，被称为桶的大型面部触须的解剖学表征在地形上是有组织的，并且高度分离。尽管单个触须的功能表征与其相应的桶对齐，但其面积范围相当大，从相应的桶沿切线平面向外扩展，从而跨越多个相邻和不相邻的桶以及间隔区域。迄今为止，单触须功能表征主要是针对其相应桶位于PMBSF中央的触须（中央触须）进行表征的。通过成像后单单元记录验证的内在信号成像，我们证明其桶位于PMBSF边界的边界触须也会引发大的活动区域，其大小与中央触须的活动区域相似，但会扩展到PMBSF之外，有时会超出初级体感皮层进入相邻的颗粒下层区域。这项研究表明，单个触须的大功能表征是大鼠触须-桶系统的基本功能特征，并且与其他研究结果相结合，表明感觉上皮上小的点状区域的大功能表征可能是一般初级感觉皮层的功能特征。
