Active Touch: Vibrissal Tactile Discrimination in the Rat

已知对触摸的敏感度在对象简单地触摸皮肤时的“被动”触摸与对象通过移动触摸而被感觉到时的“主动”触摸之间是不同的。 我们对这些差异背后的大脑机制知之甚少。 该项目利用了最近开发的一种新方法，使用啮齿动物的胡须作为模型系统。 啮齿动物积极探索表面使用其特征的“拂动”运动的胡须阵列称为面部触须。 最近的研究表明，老鼠使用触须进行的纹理辨别非常出色，与灵长类动物使用指尖进行的辨别相当，并且辨别的行为策略相似。 老鼠的胡须系统特别适合研究，因为它在解剖学上有着优雅有序的投射到大脑，而且胡须很容易进行无害的操作和观察。 该项目使用动物训练，计算机辅助运动分析和单神经细胞电生理记录的新颖组合来研究这种主动触摸。 比较了搅拌接触、外周神经元活动和中央皮层神经元活动之间的关系，并探讨了多个胡须和感觉体验的作用。 这项工作的结果将产生超越躯体感觉神经科学的影响，更好地理解动物如何使用主动驱动的感觉行为，感觉体验和学习如何增强辨别力，以及更普遍的大脑如何获取和处理信息。

Sensitivity to touch is known to be different between "passive" touch when an object simply touches the skin, and "active" touch when an object is felt by moving touch. We know very little about the mechanisms in the brain that underlie these differences. This project exploits a novel approach recently developed using rodent whiskers as a model system. Rodents actively explore surfaces using characteristic "whisking" movements of their array of whiskers called facial vibrissae. Recent work has shown that texture discrimination by rats using their vibrissae is excellent, comparable to primates using their fingertips, and that the behavioral strategies for discrimination are similar. The rat whisker system is particularly well-suited for study because a lot is known about its elegant anatomical orderly projection to the brain, and because the whiskers are easily accessible for harmless manipulation and observation. This project uses a novel combination of animal training, computer-assisted movement analysis, and electrophysiological recordings from single nerve cells to investigate this active touch. The relationship between whisking contact, activity in peripheral neurons and activity in central cortical neurons is compared, and the role of multiple whiskers and of sensory experience is explored. Results from this work will have an impact beyond somatosensory neuroscience toward better understanding how animals use actively driven sensory behavior in general, how sensory experience and learning enhance discrimination, and more generally how the brain acquires and processes information.