Li Zhaohui, Gao Mengyu, Wang Yongtian
School of Information Science and Engineering, Yanshan University, Qinhuangdao, China.
Hebei Key Laboratory of Information Transmission and Signal Processing, Yanshan University, Qinhuangdao, China.
Front Comput Neurosci. 2019 Jul 11;13:47. doi: 10.3389/fncom.2019.00047. eCollection 2019.
Orientation selectivity is a fundamental property of visual cortical neurons and plays a crucial role in pattern perception. Although many studies have dedicated to explain how the orientation selectivity emerged, the mechanism underlying orientation selectivity is still not clear. In this work, we investigated the synchronization between spikes and local field potentials (LFP) in gamma band, with the aim of providing a new avenue to analyze the orientation selectivity. The experimental data were recorded by utilizing two chronically implanted multi-electrode arrays, where each array consisted of 48 electrodes and was placed over V1 and V4, respectively, in two macaques performing a selective visual attention task. An unbiased and robust measure for quantifying the synchronization between spikes and LFP was employed in the analysis process, which is termed as spike-triggered correlation matrix synchronization (SCMS) and performs reliably for limited samples of data. We observed the spike-LFP synchronization in three cases, i.e., spikes and LFP in V1, spikes and LFP in V4, spikes in V4 and LFP in V1. From the orientation tuning curves based on the spike-LFP synchronization, it is found that there is a strong correlation between the synchronization and grating orientation. The neurons in both V1 and V4 exhibit orientation selectivity, but V1 is stronger. In addition, the spike-LFP synchronization strength between V1 and V4 also shows orientation selectivity to drifting gratings. It means that the synchronization not only reflects the basic features of visual stimulation, but also describes the orientation tuning characteristics of neurons in different regions. Our results suggest that the spike-LFP synchronization can be used as an alternative and effective method to study the mechanism for generating orientation selectivity of visual neurons.
方向选择性是视觉皮层神经元的一项基本特性，在模式感知中起着关键作用。尽管许多研究致力于解释方向选择性是如何产生的，但其潜在机制仍不清楚。在这项工作中，我们研究了伽马波段中尖峰与局部场电位（LFP）之间的同步性，旨在为分析方向选择性提供一条新途径。实验数据是通过使用两个长期植入的多电极阵列记录的，每个阵列由48个电极组成，分别放置在两只执行选择性视觉注意任务的猕猴的V1区和V4区上方。在分析过程中采用了一种无偏且稳健的方法来量化尖峰与LFP之间的同步性，该方法被称为尖峰触发相关矩阵同步（SCMS），并且对于有限的数据样本能够可靠地执行。我们观察了三种情况下的尖峰-LFP同步，即V1区的尖峰与LFP、V4区的尖峰与LFP、V4区的尖峰与V1区的LFP。从基于尖峰-LFP同步的方向调谐曲线可以发现，同步性与光栅方向之间存在很强的相关性。V1区和V4区的神经元都表现出方向选择性，但V1区更强。此外，V1区和V4区之间的尖峰-LFP同步强度对漂移光栅也表现出方向选择性。这意味着同步性不仅反映了视觉刺激的基本特征，还描述了不同区域神经元的方向调谐特性。我们的结果表明，尖峰-LFP同步可以作为一种替代且有效的方法来研究视觉神经元方向选择性产生的机制。
