Lakatos Peter, Shah Ankoor S, Knuth Kevin H, Ulbert Istvan, Karmos George, Schroeder Charles E
Cognitive Neuroscience and Schizophrenia Program, Nathan Kline Inst., Orangeburg, New York 10962, USA.
J Neurophysiol. 2005 Sep;94(3):1904-11. doi: 10.1152/jn.00263.2005. Epub 2005 May 18.
EEG oscillations are hypothesized to reflect cyclical variations in the neuronal excitability, with particular frequency bands reflecting differing spatial scales of brain operation. However, despite decades of clinical and scientific investigation, there is no unifying theory of EEG organization, and the role of ongoing activity in sensory processing remains controversial. This study analyzed laminar profiles of synaptic activity [current source density CSD] and multiunit activity (MUA), both spontaneous and stimulus-driven, in primary auditory cortex of awake macaque monkeys. Our results reveal that the EEG is hierarchically organized; delta (1-4 Hz) phase modulates theta (4-10 Hz) amplitude, and theta phase modulates gamma (30-50 Hz) amplitude. This oscillatory hierarchy controls baseline excitability and thus stimulus-related responses in a neuronal ensemble. We propose that the hierarchical organization of ambient oscillatory activity allows auditory cortex to structure its temporal activity pattern so as to optimize the processing of rhythmic inputs.
脑电图振荡被假定为反映神经元兴奋性的周期性变化，特定频段反映大脑运作的不同空间尺度。然而，尽管经过了数十年的临床和科学研究，仍没有关于脑电图组织的统一理论，且持续活动在感觉处理中的作用仍存在争议。本研究分析了清醒猕猴初级听觉皮层中自发和刺激驱动的突触活动[电流源密度CSD]和多单位活动（MUA）的层状分布。我们的结果表明，脑电图是分层组织的；δ波（1-4赫兹）相位调制θ波（4-10赫兹）振幅，而θ波相位调制γ波（30-50赫兹）振幅。这种振荡层次控制基线兴奋性，从而控制神经元集合中与刺激相关的反应。我们提出，环境振荡活动的分层组织使听觉皮层能够构建其时间活动模式，从而优化对节律性输入的处理。
