Ghazanfar A A, Nicolelis M A
Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
J Neurophysiol. 1997 Jul;78(1):506-10. doi: 10.1152/jn.1997.78.1.506.
Rats explore tangible objects in a manner such that, at any given moment in time, multiple facial whiskers simultaneously contact the surface of the object. Although both thalamic and cortical neurons responsible for processing such tactile information have large, multiwhisker receptive fields, it remains unclear what kinds of computations can be carried out by these neuronal populations when behaviorally relevant multiwhisker stimuli are used. By simultaneously recording the activity of up to 78 cortical and thalamic neurons per animal, we observed that the magnitude of sensory responses and the spatial spread of ensemble activity increased in a nonlinear fashion according to the extent and spatial orientation of the multiwhisker stimuli. Supralinear responses were seen more frequently with vertically than with horizontally oriented stimuli. These data suggest that thalamocortical interactions in the rat somatosensory system can generate complex spatial transformations of multiwhisker stimuli that go beyond the classic inhibitory interactions previously observed.
在任何给定时刻，多根面部触须会同时接触物体表面。尽管负责处理此类触觉信息的丘脑和皮层神经元都具有大的多触须感受野，但当使用与行为相关的多触须刺激时，这些神经元群体能够进行何种计算仍不清楚。通过同时记录每只动物多达78个皮层和丘脑神经元的活动，我们观察到，根据多触须刺激的范围和空间方向，感觉反应的幅度和整体活动的空间扩展呈非线性增加。与水平方向的刺激相比，垂直方向的刺激更频繁地出现超线性反应。这些数据表明，大鼠体感系统中的丘脑皮层相互作用可以产生多触须刺激的复杂空间转换，这超出了先前观察到的经典抑制性相互作用。
