Laminar differences in sizes, shapes, and response profiles of cutaneous receptive fields in the rat SI cortex
Laminar differences in sizes, shapes, and response profiles of cutaneous receptive fields in the rat SI cortex
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大鼠 SI 皮层皮肤感受野的大小、形状和反应曲线的层状差异
DOI：
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发表时间：
2004
影响因子：
2
通讯作者：
John K. Chapin
中科院分区：
文献类型：
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作者：
John K. Chapin
摘要定量技术被用来证明皮层层的差异，在皮肤感受野（RF的）在大鼠SI皮层。二维和三维（2-D和3-D）的RF地图构建显示单个神经元的响应标准化的点状刺激的每个矩阵的点在皮肤上或mystyrus触须垫。这些不仅允许可视化这种RF的整体尺寸，而且还允许可视化它们的形状和“响应曲线”。最初的实验表明，这些RF的大小和响应曲线是相似的，无论是通过皮肤的正弦机械振动，点状触摸，或直接皮内电刺激映射。该方法用于定量测定在SI皮质的前爪区域中的不同深度处记录的单个单元的RF的远侧长度。这些RF长度作为皮质深度的函数的曲线图显示，在颗粒层（IV和深III）中发现了最小的RF。在颗粒上层中发现了高达两倍大小的RF，而在颗粒下层中则高达三倍大小。颗粒层中的RF的3-D图显示出尖锐的中央响应峰，其被到RF边界的非常陡峭的下降所包围。在晶须区域中，颗粒层RF的形状通常为圆形并且包含1-4个晶须。相比之下，在晶粒上的层，他们往往是细长的形状，并定向沿着行或列的晶须。在第五层的RF类似于大的，高的平台，往往支持明确分离的峰。RF的映射在前爪和后爪地区是相似的，但即使在颗粒层，往往略有延长沿着肢轴。在SI的所有区域中，颗粒层RF的位置和形状似乎都被保存为柱中其他地方遇到的其他地形上更异质的RF的子集。这些发现可能与大鼠SI中轴突连接的模式相关。
SummaryQuantitative techniques were used to demonstrate cortical layer differences in cutaneous receptive fields (RF's) in the rat SI cortex. Two- and three-dimensional (2-D and 3-D) RF maps were constructed showing the responsiveness of single neurons to standardized punctate stimulation of each of a matrix of points on the skin or the mystacial vibrissa pad. These allowed a visualization not only of the overall sizes of such RF's, but also their shape and “response profile”. Initial experiments showed that the sizes and response profiles of such RF's were similar whether they were mapped by sinusoidal mechanical vibration of skin, punctate touch, or direct intracutaneous electrical stimulation. This method was used to quantitatively determine distoproximal lengths of RF's of single units recorded at different depths in the forepaw area of the SI cortex. Plots of these RF lengths as a function of cortical depth showed that the smallest RF's were found in the granular layers (IV and deep III). RF's up to double that size were found in supragranular layers, and up to triple that size in infragranular layers. 3-D maps of RF's in the granular layers showed sharp central response peaks surrounded by very steep dropoffs to the RF boundaries. In the whisker areas, granular layer RF's were typically circular in shape and contained from 1–4 whiskers. By contrast, in supragranular layers they were often elongated in shape, and were oriented along rows or columns of whiskers. RF's in layer V resembled large, high plateaus, often supporting clearly separated peaks. RF's mapped in the fore- and hindpaw areas were similar, but, even in the granular layers, were often slightly elongated along the limb axis. In all regions of the SI, both the locations and shapes of the granular layer RF's appeared to be conserved as subsets of other more topographically heterogeneous RF's encountered elsewhere in the column. These findings may correlate with patterns of axonal connectivity in the rat SI.