Response properties of whisker-related neurons in rat second somatosensory cortex
Response properties of whisker-related neurons in rat second somatosensory cortex
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DOI：
10.1152/jn.00262.2004
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发表时间：
2004-10-01
影响因子：
2.5
通讯作者：
Keller, A
中科院分区：
文献类型：
--
作者：
Kwegyir-Afful, EE;Keller, A
除了初级体感皮层（SI）外，所有哺乳动物的大脑皮层都含有第二体感区（SII）；然而，SII的功能在很大程度上是未知的。我们的目的是通过比较该区域的须相关神经元与SII对应神经元的响应特性来探索SII的功能。我们获得了麻醉大鼠对压电装置引起的须偏转的响应的细胞外单位记录，并比较了SI桶（第四层）神经元和SII（第二层至第六层）神经元的响应特性。两个皮层区域的神经元具有相似的反应潜伏期和自发活动水平。然而，SI和SII神经元在几个重要特性上有所不同。SII神经元的感受野至少是桶状神经元的五倍大，它们对几个主须的反应同样强烈。SII神经元的响应幅度明显小于SI神经元，SII神经元对晶须偏转角度的选择性更强。此外，虽然SII神经元的快速峰（抑制性）和规律峰（兴奋性）单元具有不同的自发和诱发活动水平，并且对刺激开始和抵消的反应不同，但SII神经元在这些特性上没有显着差异。SII神经元的反应特性表明，它们是由丘脑输入驱动的，丘脑输入是旁神经系统的一部分。因此，与须相关的输入是由一个包括SI的神经系统和一个处理躯体感觉互补方面的神经系统并行处理的。
In addition to a primary somatosensory cortex ( SI), the cerebral cortex of all mammals contains a second somatosensory area (SII); however, the functions of SII are largely unknown. Our aim was to explore the functions of SII by comparing response properties of whisker-related neurons in this area with their counterparts in the SI. We obtained extracellular unit recordings from narcotized rats, in response to whisker deflections evoked by a piezoelectric device, and compared response properties of SI barrel ( layer IV) neurons with those of SII ( layers II to VI) neurons. Neurons in both cortical areas have similar response latencies and spontaneous activity levels. However, SI and SII neurons differ in several significant properties. The receptive fields of SII neurons are at least five times as large as those of barrel neurons, and they respond equally strongly to several principal whiskers. The response magnitude of SII neurons is significantly smaller than that of neurons in SI, and SII neurons are more selective for the angle of whisker deflection. Furthermore, whereas in SI fast-spiking ( inhibitory) and regular-spiking ( excitatory) units have different spontaneous and evoked activity levels and differ in their responses to stimulus onset and offset, SII neurons do not show significant differences in these properties. The response properties of SII neurons suggest that they are driven by thalamic inputs that are part of the paralemniscal system. Thus whisker-related inputs are processed in parallel by a lemniscal system involving SI and a paralemniscal system that processes complimentary aspects of somatosensation.