Gamma oscillations (30–70 Hz) have been hypothesized to play a role in cortical function. Most of the proposed mechanisms involve rhythmic modulation of neuronal excitability at gamma frequencies, leading to modulation of spike timing relative to the rhythm. I first show that the gamma band could be more privileged than other frequencies in observing spike–field interactions even in the absence of genuine gamma rhythmicity and discuss several biases in spike–gamma phase estimation. I then discuss the expected spike–gamma phase according to several hypotheses. Inconsistent with the phase-coding hypothesis (but not with others), the spike–gamma phase does not change with changes in stimulus intensity or attentional state, with spikes preferentially occurring 2–4 ms before the trough, but with substantial variability. However, this phase relationship is expected even when gamma is a byproduct of excitatory–inhibitory interactions. Given that gamma occurs in short bursts, I argue that the debate over the role of gamma is a matter of semantics.

中文翻译：

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视觉皮层中的尖峰-伽玛相位关系

假设伽马振荡（30-70 Hz）在皮质功能中发挥作用。大多数提出的机制涉及伽玛频率下神经元兴奋性的节律性调节，导致相对于节律的尖峰时间的调节。我首先表明，即使在没有真正的伽马节律性的情况下，伽马波段在观察尖峰-场相互作用方面也比其他频率更有优势，并讨论了尖峰-伽马相位估计中的几个偏差。然后我根据几个假设讨论预期的尖峰-伽马相。与相位编码假设不一致（但与其他假设不同），尖峰-伽马相位不会随着刺激强度或注意力状态的变化而变化，尖峰优先出现在波谷之前 2-4 毫秒，但具有很大的可变性。然而，即使伽马是兴奋-抑制相互作用的副产品，这种相位关系也是预期的。鉴于伽马发生在短时间内，我认为关于伽马作用的争论是语义问题。