Encoding of stimulus frequency and sensor motion in the posterior medial thalamic nucleus
Encoding of stimulus frequency and sensor motion in the posterior medial thalamic nucleus
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DOI：
10.1152/jn.01322.2007
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发表时间：
2008-08-01
影响因子：
2.5
通讯作者：
Keller, Asaf
中科院分区：
文献类型：
--
作者：
Masri, Radi;Bezdudnaya, Tatiana;Keller, Asaf
在所有的感觉系统中，信息是沿着沿着的几条信息流进行处理的。在触须-桶皮质系统中，包括丘系系统和鲜为人知的丘系系统。后内侧核（POm）是与后一通路相关的丘脑结构。已有的研究表明，POm反应时间与刺激频率呈正相关，与反应持续时间呈负相关，这为锁相环-时间解码刺激频率提供了依据。我们测试了这一假设，通过分析POm神经元，在清醒和麻醉大鼠，触须偏转在0.3和11赫兹之间的频率的反应lavidae。我们没有发现显着的，系统的刺激频率和POM反应的潜伏期或持续时间之间的相关性。我们从清醒大鼠、不同麻醉剂下的大鼠以及网状激活系统受到刺激的麻醉大鼠的记录中获得了类似的发现。这些发现表明，刺激频率并不可靠地反映在POm神经元的反应潜伏期。我们还测试了POm神经元优先响应传感器运动的假设，也就是说，它们响应于在空气中搅拌，没有接触。我们记录清醒，头部束缚大鼠，同时监测触须运动。所有的POM神经元响应被动的胡须偏转，但没有响应非接触搅拌。因此，像它们在三叉神经节中的对应物一样，POm神经元可能无法可靠地编码搅拌运动学。这些观察结果表明，POM神经元可能不会忠实地编码触须输入，以提供可靠的信息触须运动或接触。
In all sensory systems, information is processed along several parallel streams. In the vibrissa-to-barrel cortex system, these include the lemniscal system and the lesser-known paralemniscal system. The posterior medial nucleus (POm) is the thalamic structure associated with the latter pathway. Previous studies suggested that POm response latencies are positively correlated with stimulation frequency and negatively correlated with response duration, providing a basis for a phase locked loop-temporal decoding of stimulus frequency. We tested this hypothesis by analyzing response latencies of POm neurons, in both awake and anesthetized rats, to vibrissae deflections at frequencies between 0.3 and 11 Hz. We found no significant, systematic correlation between stimulation frequency and the latency or duration of POm responses. We obtained similar findings from recording in awake rats, in rats under different anesthetics, and in anesthetized rats in which the reticular activating system was stimulated. These findings suggest that stimulus frequency is not reliably reflected in response latency of POm neurons. We also tested the hypothesis that POm neurons respond preferentially to sensor motion, that is, they respond to whisking in air, without contacts. We recorded from awake, head-restrained rats while monitoring vibrissae movements. All POm neurons responded to passive whisker deflections, but none responded to noncontact whisking. Thus like their counterparts in the trigeminal ganglion, POm neurons may not reliably encode whisking kinematics. These observations suggest that POm neurons might not faithfully encode vibrissae inputs to provide reliable information on vibrissae movements or contacts.