Sanchez-Jimenez A, Panetsos F, Murciano A
Neurocomputing and Neurorobotics Research Group, Complutense University of Madrid, Avda Arcos de Jalon 118, 28037 Madrid, Spain.
Neuroscience. 2009 Apr 21;160(1):212-26. doi: 10.1016/j.neuroscience.2009.01.075.
The rat facial whiskers form a high-resolution sensory apparatus for tactile information coding and are used by these animals for the exploration and perception of their environment. Previous work on the rat vibrissae system obtained evidence for vibration-based feature extraction by the whiskers, texture classification by the cortical neurons, and "low-pass", "high-pass", and "band-pass" filtering properties in both thalamic and cortical neurons. However, no data are available for frequency-dependent information processing in the brainstem sensory trigeminal complex (STC), the first relay station of the vibrissae pathway. In the present paper, we studied the frequency-dependent processing characteristics of the STC nuclei that mainly project to the thalamus, nuclei principalis, and interpolaris. This is the first time that STC nuclei have been studied together via a wide range of stimulation frequencies (1-40 Hz), four different and complementary metrics, and the same experimental protocol. Moreover, the role of corticofugal projection to these nuclei as well as the influence of input from the whiskers has been analyzed. We show that both nuclei perform frequency-dependent coding of tactile information: low pass and band-pass filtering occurs for the spiking rate in short post-stimuli time intervals, high-pass and band-pass filtering occurs for the spiking rate in long trains of stimuli, and an increase of response latencies and low pass filtering occurs for phase-locked stimuli. These information-processing characteristics are neither imposed by the sensorimotor cortex nor introduced by the afferent fibres. The sensorimotor cortex exerts a distinct modulatory effect on each nucleus.
大鼠的面部触须形成了一个用于触觉信息编码的高分辨率感觉器官，这些动物利用它来探索和感知周围环境。先前关于大鼠触须系统的研究获得了以下证据：触须基于振动进行特征提取，皮层神经元进行纹理分类，以及丘脑和皮层神经元具有“低通”“高通”和“带通”滤波特性。然而，关于触须通路的第一中继站——脑干感觉三叉神经复合体（STC）中频率依赖性信息处理的数据尚无报道。在本文中，我们研究了主要投射到丘脑、主核和极间核的STC核的频率依赖性处理特征。这是首次通过广泛的刺激频率（1 - 40Hz）、四种不同且互补的指标以及相同的实验方案对STC核进行综合研究。此外，还分析了皮质离心投射对这些核的作用以及触须输入的影响。我们发现，这两个核都对触觉信息进行频率依赖性编码：在短刺激后时间间隔内，放电率呈现低通和带通滤波；在长刺激序列中，放电率呈现高通和带通滤波；对于锁相刺激，反应潜伏期增加且呈现低通滤波。这些信息处理特征既不是由感觉运动皮层强加的，也不是由传入纤维引入的。感觉运动皮层对每个核都发挥着独特的调节作用。
