Timofeeva Elena, Mérette Chantal, Emond Claudia, Lavallée Philippe, Deschênes Martin
Centre de Recherche Université Laval-Robert Giffard, Québec G1J 2G3, Canada.
J Neurosci. 2003 Nov 19;23(33):10717-23. doi: 10.1523/JNEUROSCI.23-33-10717.2003.
A double-labeling protocol was used to determine how cells with different angular preferences to whisker motion distribute across the dimensions of a barreloid in the ventral posterior medial nucleus of the rat thalamus. Individual barreloids were labeled retrogradely by injecting Fluoro-Gold in identified barrel columns, and single relay cells (n = 30) pertaining to the labeled barreloids were stained juxtacellularly with Neurobiotin after determination of their angular tuning preference to controlled whisker deflection. Results show that cells with like angular preference are clustered within the barreloids. Those best tuned to forward and upward directions are located principally in the dorsal sector of the barreloid, whereas those best tuned to backward and downward motion are located principally in the central and ventral sectors, respectively. The relationship between cell location and angular preference was assessed by regression, cluster, and discriminant analysis. Together, these tests indicate that barreloids contain a map of shifting angular preference that transposes along the length of a barreloid directional property imposed at the periphery by the circumferential distribution of receptors around the vibrissa follicles.
采用双标记方案来确定对触须运动具有不同角度偏好的细胞如何分布在大鼠丘脑腹后内侧核中桶状小体的各个维度上。通过向特定的桶状柱中注射荧光金对单个桶状小体进行逆行标记，在确定单个中继细胞（n = 30）对受控触须偏转的角度调谐偏好后，用神经生物素对属于标记桶状小体的单个中继细胞进行近细胞内染色。结果表明，具有相似角度偏好的细胞聚集在桶状小体内。那些对向前和向上方向调谐最佳的细胞主要位于桶状小体的背侧部分，而那些对向后和向下运动调谐最佳的细胞分别主要位于中央和腹侧部分。通过回归、聚类和判别分析评估细胞位置与角度偏好之间的关系。这些测试共同表明，桶状小体包含一个不断变化的角度偏好图谱，该图谱沿着桶状小体的长度进行转换，这种方向性属性是由触须毛囊周围受体的周向分布在周边施加的。
