Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA.
Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA.
Neuroimage. 2018 Apr 1;169:286-301. doi: 10.1016/j.neuroimage.2017.12.051. Epub 2017 Dec 22.
Natural environments elicit both phase-locked and non-phase-locked neural responses to the stimulus in the brain. The interpretation of the BOLD signal to date has been based on an association of the non-phase-locked power of high-frequency local field potentials (LFPs), or the related spiking activity in single neurons or groups of neurons. Previous studies have not examined the prediction of the BOLD signal by phase-locked responses. We examined the relationship between the BOLD response and LFPs in the same nine human subjects from multiple corresponding points in the auditory cortex, using amplitude modulated pure tone stimuli of a duration to allow an analysis of phase locking of the sustained time period without contamination from the onset response. The results demonstrate that both phase locking at the modulation frequency and its harmonics, and the oscillatory power in gamma/high-gamma bands are required to predict the BOLD response. Biophysical models of BOLD signal generation in auditory cortex therefore require revision and the incorporation of both phase locking to rhythmic sensory stimuli and power changes in the ensemble neural activity.
自然环境会在大脑中引发与刺激相关的锁相和非锁相神经反应。迄今为止，对 BOLD 信号的解释一直基于对高频局部场电位 (LFPs) 的非锁相功率的关联，或者与单个神经元或神经元群的相关尖峰活动的关联。以前的研究并未检查锁相反应对 BOLD 信号的预测。我们使用持续时间的调制纯音刺激，从听觉皮层的多个对应点检查了同一九名人类受试者的 BOLD 反应和 LFPs 之间的关系，以便在不受起始反应干扰的情况下分析持续时间的锁相。结果表明，调制频率及其谐波的锁相以及伽马/高伽马波段的振荡功率都需要预测 BOLD 反应。因此，听觉皮层中 BOLD 信号产生的生物物理模型需要进行修订，并将相位锁定到节律性感觉刺激以及整体神经活动中的功率变化结合起来。
