GABAergic inhibition in shaping the spatial frequency tuning of neurons and its contrast dependency in the dorsal lateral geniculate nucleus of cat.
GABAergic inhibition in shaping the spatial frequency tuning of neurons and its contrast dependency in the dorsal lateral geniculate nucleus of cat.
复制标题
猫背外侧膝状核中神经元空间频率调谐的 GABA 能抑制及其对比依赖性。
DOI：
10.1111/ejn.12149
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发表时间：
2013
影响因子：
3.4
通讯作者：
Kimura Akihiro
中科院分区：
文献类型：
--
作者：
Kimura A;Shimegi S;Hara S;Okamoto M;Sato H;Kimura Akihiro
为了了解GABA能抑制如何促进外侧膝状体神经元的空间频率（SF）调谐，我们研究了微电泳给药的荷包牡丹碱甲碘（BIC）和gabazine，GABA受体的拮抗剂，对高或低对比度光栅刺激的视觉反应的影响。BIC给药将尖峰响应的SF调谐曲线形状从带通变为低通。我们将在BIC条件下获得的调谐曲线作为对控制调谐曲线的估计的兴奋性贡献，然后估计在有和没有BIC的情况下记录的调谐曲线之间的差异作为估计的GABA能抑制贡献的调谐曲线。估计抑制（估计-Inh）的SF调谐曲线在细胞间变化很大，估计兴奋（估计-Ex）也是如此。尽管如此，Estimated-Inh比Estimated-Ex表现出更多的低通调谐的关系在大多数细胞中得到了很好的保留，并且该关系将Estimated-Ex的SF调谐细化为膝状体输出的带通调谐。降低刺激对比度会降低反应幅度，但不会改变带通调谐的程度。在低刺激对比度下也观察到SF调谐的GABA能细化，但比高对比度下弱，表明GABA能抑制与兴奋性输入协调调节，以保持带通调谐的程度恒定。因此，我们得出结论，在GABA能抑制的动态调节作用的基础上，带通调谐的程度在外侧膝状体中保持不变。
To understand how GABAergic inhibition contributes to the elaboration of spatial frequency (SF) tuning of neurons in the lateral geniculate nucleus, we examined the effects of the microiontophoretic administration of bicuculline methiodide (BIC) and gabazine, both antagonists of GABAAreceptors, on visual responses to grating stimuli with high or low contrasts. BIC administration changed the shape of the SF tuning curve of the spike response from band‐pass to low‐pass. We took the tuning curve obtained under the BIC condition as an estimated excitatory contribution to the control tuning curve and then estimated the difference between tuning curves recorded with and without BIC as the tuning curve of the estimated GABAergic inhibitory contribution. The SF tuning profile of estimated inhibition (Estimated‐Inh) varied widely from cell to cell, as did estimated excitation (Estimated‐Ex). Nonetheless, the relationship that Estimated‐Inh exhibited more low‐pass tuning than did Estimated‐Ex was well conserved in the majority of cells, and the relationship refined the SF tuning of Estimated‐Ex toward the band‐pass tuning of the geniculate output. Lowering the stimulus contrast decreased the response magnitude, but did not change the degree of band‐pass tuning. The GABAergic refinement of the SF tuning was also observed at low stimulus contrast, but was weaker than at high contrast, suggesting that GABAergic inhibition is regulated in coordination with excitatory inputs to keep the degree of the band‐pass tuning constant. We therefore concluded that the degree of band‐pass tuning is conserved contrast invariantly in the lateral geniculate nucleus on the basis of the dynamic regulatory action of GABAergic inhibition.