The array of vibrissae on a rat’s face is the first stage in a high-resolution tactile sensing system. Progressing from rostral to caudal in any vibrissae row results in an increase in whisker length and thickness. This may, in turn, provide a systematic map of separate tactile channels governed by the mechanical properties of the whiskers. To examine whether this map is expressed in a location-dependent transformation of tactile signals into whisker vibrations and neuronal responses, we monitored whiskers’ movements across various surfaces and edges. We found a robust rostral-caudal (R-C) gradient of tactile information transmission in which rostral shorter vibrissae displayed a higher sensitivity and bigger differences in response to different textures, whereas longer caudal vibrissae were less sensitive. This gradient is evident in several dynamic properties of vibrissae trajectories. As rodents sample the environment with multiple vibrissae, we found that combining tactile signals from multiple vibrissae resulted in an increased sensitivity and bigger differences in response to the different textures. Nonetheless, we found that texture identity is not represented spatially across the whisker pad. Based on the responses of first-order sensory neurons, we found that they adhere to the tactile information conveyed by the vibrissae. That is, neurons innervating rostral vibrissae were better suited for texture discrimination, whereas neurons innervating caudal vibrissae were more suited for edge detection. These results suggest that the whisker array in rodents forms a sensory structure in which different facets of tactile information are transmitted through location-dependent gradient of vibrissae on the rat’s face.

老鼠脸上的触须排列是高分辨率触觉感应系统的第一步。在任何触须行中从尾状向尾状发展都会导致晶须长度和厚度增加。反过来，这可以提供由晶须的机械性能控制的单独的触觉通道的系统图。为了检查该图是否以触觉信号到晶须振动和神经元响应的位置相关转换来表达，我们监测了晶须在各种表面和边缘的运动。我们发现触觉信息传递的鲁棒的尾-尾（RC）梯度，其中尾短的触须表现出较高的灵敏度和对不同纹理的响应差异较大，而较长的尾触须则较不敏感。该斜率在触须轨迹的几个动态特性中很明显。当啮齿动物对具有多个触须的环境进行采样时，我们发现将来自多个触须的触觉信号相结合会导致灵敏度提高，并且对不同纹理的响应差异更大。尽管如此，我们发现在晶须垫上并未在空间上表示纹理标识。基于一阶感觉神经元的响应，我们发现它们遵守触须传达的触觉信息。也就是说，支配尾状触须的神经元更适合于纹理识别，而支配尾状触须的神经元更适合于边缘检测。