Spatiotemporal gating of sensory inputs in thalamus during quiescent and activated states
Spatiotemporal gating of sensory inputs in thalamus during quiescent and activated states
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DOI：
10.1523/jneurosci.3229-05.2005
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发表时间：
2005-11-23
影响因子：
5.3
通讯作者：
Castro-Alamancos, MA
中科院分区：
文献类型：
--
作者：
Aguilar, JR;Castro-Alamancos, MA
丘脑的主要作用是根据行为状态的规定将感觉输入传递到新皮层。因此，行为状态的变化可能会改变丘脑皮层感受野的时间和空间特性。我们比较了单细胞的感受野在腹后内侧丘脑（VPM）的麻醉大鼠在静止状态和唤醒（激活）状态。在静止状态下，VPM细胞对主须（PW）的刺激做出反应，并且可能对一个或几个相邻的须（AW）做出适度的反应。无论是在广泛性前脑激活或选择性丘脑激活所造成的卡巴胆碱灌注VPM，AWs的反应增强，使VPM感受野变得更大。在三叉神经主核水平没有观察到这种增大，表明它起源于丘脑。有趣的是，尽管激活期间AW反应增加，但PW和AW的同时偏转产生了与PW反应相似的VPM反应，就好像AW没有受到刺激一样。这种感觉反应的非线性总和在静止和激活状态下都存在。总之，丘脑在静止状态下抑制感受野的兴奋性环绕（AW），并在觉醒期间扩大该环绕。但是，当中心（PW）和周围（AWs）同时受到刺激时，丘脑皮层细胞仅代表感受野的中心（PW）。
The main role of the thalamus is to relay sensory inputs to the neocortex according to the regulations dictated by behavioral state. Hence, changes in behavioral state are likely to transform the temporal and spatial properties of thalamocortical receptive fields. We compared the receptive fields of single cells in the ventroposterior medial thalamus ( VPM) of urethane-anesthetized rats during quiescent states and during aroused ( activated) states. During quiescent states, VPM cells respond to stimulation of a principal whisker ( PW) and may respond modestly to one or a few adjacent whiskers ( AWs). During either generalized forebrain activation or selective thalamic activation caused by carbachol infusion in the VPM, the responses to AWs enhance so that VPM receptive fields become much larger. Such enlargement is not observed at the level of the principal trigeminal nucleus, indicating that it originates within the thalamus. Interestingly, despite the increase in AW responses during activation, simultaneous deflection of the PW and AWs produced VPM responses that resembled the PW response, as if the AWs were not stimulated. This nonlinear summation of sensory responses was present during both quiescent and activated states. In conclusion, the thalamus suppresses the excitatory surround ( AWs) of the receptive field during quiescent states and enlarges this surround during arousal. But, thalamocortical cells represent only the center ( PW) of the receptive field when the center ( PW) and surround ( AWs) are stimulated simultaneously.