Lee Daeyeol
Department of Brain and Cognitive Sciences, Center for Visual Science, University of Rochester, Rochester, New York 14627, USA.
J Neurosci. 2003 Jul 30;23(17):6798-809. doi: 10.1523/JNEUROSCI.23-17-06798.2003.
Neural activity recorded in behaving animals is nonstationary, making it difficult to determine factors influencing its temporal patterns. In the present study, rhesus monkeys were trained to produce a series of visually guided hand movements according to the changes in target locations, and multichannel single-neuron activity was recorded from the caudal supplementary motor area. Coherent oscillations in neural activity were analyzed using the wavelet cross-spectrum, and its statistical significance was evaluated using various methods based on surrogate spike trains and trial shuffling. A population-averaged wavelet cross-spectrum displayed a strong tendency for oscillatory activity in the gamma frequency range (30 approximately 50 Hz) to synchronize immediately before and after the onset of movement target. The duration of synchronized oscillations in the gamma frequency range increased when the onset of the next target was delayed. In addition, analysis of individual neuron pairs revealed that many neuron pairs also displayed coherent oscillations in the beta frequency range (15-30 Hz). Coherent beta frequency oscillations were less likely to be synchronized than gamma frequency oscillations, consistent with the fact that coherent beta frequency oscillations were not clearly seen in the population-averaged cross-spectrum. For a given neuron pair, the time course and phase of coherent oscillations were often similar across different movements. These results are consistent with the proposal that synchronized oscillations in the gamma frequency range might be related to the anticipation of behaviorally relevant events and the contextual control of cortical information flow.
在行为动物中记录到的神经活动是非平稳的，这使得确定影响其时间模式的因素变得困难。在本研究中，恒河猴被训练根据目标位置的变化产生一系列视觉引导的手部动作，并从尾侧辅助运动区记录多通道单神经元活动。使用小波互谱分析神经活动中的相干振荡，并使用基于替代脉冲序列和试验重排的各种方法评估其统计显著性。群体平均小波互谱显示，在运动目标开始之前和之后，γ频率范围（30至50赫兹）内的振荡活动有强烈的同步趋势。当下一个目标的开始延迟时，γ频率范围内同步振荡的持续时间增加。此外，对单个神经元对的分析表明，许多神经元对在β频率范围（15至30赫兹）内也表现出相干振荡。与在群体平均互谱中未清晰看到相干β频率振荡这一事实一致，相干β频率振荡比γ频率振荡更不容易同步。对于给定的神经元对，相干振荡的时间进程和相位在不同运动中通常相似。这些结果与以下提议一致，即γ频率范围内的同步振荡可能与行为相关事件的预期以及皮质信息流的情境控制有关。
