Laboratory of Cognitive and Behavioral Neuroscience, Department of Health and Sportsscience, Graduate School of Frontier Biosciences, Osaka University Osaka, Japan.
Laboratory of Cognitive and Behavioral Neuroscience, Department of Health and Sportsscience, Graduate School of Medicine, Osaka University Osaka, Japan.
Front Syst Neurosci. 2013 Dec 9;7:103. doi: 10.3389/fnsys.2013.00103. eCollection 2013.
The spatial structure of the receptive field (RF) of cat lateral geniculate nucleus (LGN) neurons is significantly elliptical, which may provide a basis for the orientation tuning of LGN neurons, especially at high spatial frequency stimuli. However, the input mechanisms generating this elliptical RF structure are poorly defined. We therefore compared the spatiotemporal RF structures of pairs of retinal ganglion cells (RGCs) and LGN neurons that form monosynaptic connections based on the cross-correlation analysis of their firing activities. We found that the spatial RF structure of both RGCs and LGN neurons were comparably elliptical and oriented in a direction toward the area centralis. Additionally, the spatial RF structures of pairs with the same response sign were often overlapped and similarly oriented. We also found there was a small population of pairs with RF structures that had the opposite response sign and were spatially displaced and independently oriented. Finally, the temporal RF structure of an RGC was tightly correlated with that of its target LGN neuron, though the response duration of the LGN neuron was significantly longer. Our results suggest that the elliptical RF structure of an LGN neuron is mainly inherited from the primary projecting RGC and is affected by convergent inputs from multiple RGCs. We discuss how the convergent inputs may enhance the stimulus feature sensitivity of LGN neurons.
猫外侧膝状体核（LGN）神经元的感受野（RF）的空间结构明显呈椭圆形，这可能为 LGN 神经元的方位调谐提供基础，尤其是在高空间频率刺激下。然而，产生这种椭圆形 RF 结构的输入机制尚未明确。因此，我们通过对其放电活动的互相关分析，比较了基于单突触连接形成的一对视网膜神经节细胞（RGC）和 LGN 神经元的时空 RF 结构。我们发现，RGC 和 LGN 神经元的空间 RF 结构都具有相似的椭圆形，并且朝向中央凹方向定向。此外，具有相同反应特征的对的空间 RF 结构通常重叠且具有相似的方向。我们还发现，有一小部分对的 RF 结构具有相反的反应特征，并且空间上移位且方向独立。最后，RGC 的时间 RF 结构与目标 LGN 神经元的时间 RF 结构紧密相关，尽管 LGN 神经元的反应持续时间明显更长。我们的结果表明，LGN 神经元的椭圆形 RF 结构主要来自于其主要投射的 RGC，并受到来自多个 RGC 的会聚输入的影响。我们讨论了会聚输入如何增强 LGN 神经元对刺激特征的敏感性。
