Department of Biological Sciences, State University of New York Optometry, New York, New York 10036, USA.
J Neurosci. 2012 Aug 15;32(33):11396-413. doi: 10.1523/JNEUROSCI.0429-12.2012.
Recordings from local field potentials (LFPs) are becoming increasingly common in research and clinical applications, but we still have a poor understanding of how LFP stimulus selectivity originates from the combined activity of single neurons. Here, we systematically compared the stimulus selectivity of LFP and neighboring single-unit activity (SUA) recorded in area primary visual cortex (V1) of awake primates. We demonstrate that LFP and SUA have similar stimulus preferences for orientation, direction of motion, contrast, size, temporal frequency, and even spatial phase. However, the average SUA had 50 times better signal-to-noise, 20% higher contrast sensitivity, 45% higher direction selectivity, and 15% more tuning depth than the average LFP. Low LFP frequencies (<30 Hz) were most strongly correlated with the spiking frequencies of neurons with nonlinear spatial summation and poor orientation/direction selectivity that were located near cortical current sinks (negative LFPs). In contrast, LFP gamma frequencies (>30 Hz) were correlated with a more diverse group of neurons located near cortical sources (positive LFPs). In summary, our results indicate that low- and high-frequency LFP pool signals from V1 neurons with similar stimulus preferences but different response properties and cortical depths.
记录局部场电位 (LFPs) 在研究和临床应用中变得越来越普遍，但我们仍然不太了解 LFP 的刺激选择性如何源自单个神经元的组合活动。在这里，我们系统地比较了在清醒灵长类动物初级视觉皮层 (V1) 记录的 LFPs 和邻近的单个神经元活动 (SUA) 的刺激选择性。我们证明，LFPs 和 SUA 对方向、运动方向、对比度、大小、时间频率甚至空间相位具有相似的刺激偏好。然而，平均 SUA 的信噪比比平均 LFP 好 50 倍，对比度灵敏度高 20%，方向选择性高 45%，调谐深度高 15%。低 LFPs 频率 (<30 Hz) 与具有非线性空间总和和方向/方向选择性差的神经元的尖峰频率最密切相关，这些神经元位于皮层电流汇 (负 LFPs) 附近。相比之下，LFP 伽马频率 (>30 Hz) 与位于皮层源附近的一组更具多样性的神经元相关 (正 LFPs)。总之，我们的结果表明，来自 V1 神经元的低和高频率 LFP 池信号具有相似的刺激偏好，但具有不同的响应特性和皮层深度。
