Kim Kayeon, Kim Taekjun, Yoon Taehwan, Lee Choongkil
Department of Psychology, Seoul National University, Gwanak, Seoul, Korea.
Program of Cognitive Science, Seoul National University, Gwanak, Seoul, Korea.
PLoS One. 2015 Dec 15;10(12):e0144929. doi: 10.1371/journal.pone.0144929. eCollection 2015.
A focal visual stimulus outside the classical receptive field (RF) of a V1 neuron does not evoke a spike response by itself, and yet evokes robust changes in the local field potential (LFP). This subthreshold LFP provides a unique opportunity to investigate how changes induced by surround stimulation leads to modulation of spike activity. In the current study, two identical Gabor stimuli were sequentially presented with a variable stimulus onset asynchrony (SOA) ranging from 0 to 100 ms: the first (S1) outside the RF and the second (S2) over the RF of primary visual cortex neurons, while trained monkeys performed a fixation task. This focal and asynchronous stimulation of the RF surround enabled us to analyze the modulation of S2-evoked spike activity and covariation between spike and LFP modulation across SOA. In this condition, the modulation of S2-evoked spike response was dominantly facilitative and was correlated with the change in LFP amplitude, which was pronounced for the cells recorded in the upper cortical layers. The time course of covariation between the SOA-dependent spike modulation and LFP amplitude suggested that the subthreshold LFP evoked by the S1 can predict the magnitude of upcoming spike modulation.
位于V1神经元经典感受野（RF）之外的局部视觉刺激本身不会引发尖峰反应，但却能引起局部场电位（LFP）的显著变化。这种阈下LFP为研究周边刺激引起的变化如何导致尖峰活动的调制提供了独特的机会。在当前研究中，两个相同的Gabor刺激以0至100毫秒的可变刺激起始异步（SOA）顺序呈现：第一个（S1）在RF之外，第二个（S2）在初级视觉皮层神经元的RF上，同时训练猴子执行注视任务。对RF周边的这种局部且异步的刺激使我们能够分析S2诱发的尖峰活动的调制以及整个SOA范围内尖峰与LFP调制之间的协变。在这种情况下，S2诱发的尖峰反应的调制主要是促进性的，并且与LFP振幅的变化相关，这在皮质上层记录的细胞中尤为明显。SOA依赖性尖峰调制与LFP振幅之间协变的时间进程表明，由S1诱发的阈下LFP可以预测即将到来的尖峰调制的幅度。
