Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
Neuron. 2010 Sep 9;67(5):885-96. doi: 10.1016/j.neuron.2010.08.004.
Neuronal oscillations in the gamma band (30-80 Hz) have been suggested to play a central role in feature binding or establishing channels for neural communication. For these functions, the gamma rhythm frequency must be consistent across neural assemblies encoding the features of a stimulus. Here we test the dependence of gamma frequency on stimulus contrast in V1 cortex of awake behaving macaques and show that gamma frequency increases monotonically with contrast. Changes in stimulus contrast over time leads to a reliable gamma frequency modulation on a fast timescale. Further, large stimuli whose contrast varies across space generate gamma rhythms at significantly different frequencies in simultaneously recorded neuronal assemblies separated by as little as 400 microm, making the gamma rhythm a poor candidate for binding or communication, at least in V1. Instead, our results suggest that the gamma rhythm arises from local interactions between excitation and inhibition.
伽马波段（30-80 Hz）的神经元振荡被认为在特征绑定或建立神经通讯通道方面发挥着核心作用。对于这些功能，编码刺激特征的神经组件的伽马节律频率必须在整个频率范围内保持一致。在这里，我们在清醒活动猕猴的 V1 皮层中测试了伽马频率对刺激对比度的依赖性，并表明伽马频率随对比度单调增加。随着时间的推移，刺激对比度的变化会导致快速时标上的伽马频率调制可靠。此外，大的刺激物，其对比度在空间上变化，会在同时记录的神经元组件中产生显著不同频率的伽马节律，这些神经元组件之间的间隔只有 400 微米，这使得伽马节律不太适合作为绑定或通讯的候选者，至少在 V1 是这样。相反，我们的结果表明，伽马节律是由兴奋和抑制之间的局部相互作用引起的。
