Hutchison R Matthew, Hashemi Nikoo, Gati Joseph S, Menon Ravi S, Everling Stefan
Department of Psychology, Harvard University, Cambridge, MA, USA; Center for Brain Science, Harvard University, Cambridge, MA, USA; Robarts Research Institute, University of Western Ontario, London, ON, Canada.
Robarts Research Institute, University of Western Ontario, London, ON, Canada; Neuroscience Graduate Program, University of Western Ontario, London, ON, Canada.
Neuroimage. 2015 Jun;113:257-67. doi: 10.1016/j.neuroimage.2015.03.062. Epub 2015 Mar 30.
Spontaneous brain activity is ubiquitous across brain structures and states. Determining the role of these metabolically costly intrinsic events may be critical for understanding the brain's fundamental physiological principles that govern cognition and behavior. To date, most investigations of large-scale fluctuations and their coupling have been conducted using electro- or magneto-encephalography, modalities that are limited in their ability to spatially resolve the origin of the signals. Invasive, electrophysiological local field potential (LFP) recordings are limited in their spatial range and studies combining the approach with functional imaging have been primarily relegated to sensory/motor areas with little basis in which to extrapolate findings to evolutionarily newer prefrontal cortical regions. Here, we acquired spontaneous fMRI data in two anesthetized macaque monkeys (Macaca fascicularis) at 7 T together with simultaneous recordings of intracortical LFPs recorded bilaterally from the prefrontal cortex (area 9/46d). High (beta-low gamma) and low (delta-theta) band-limited power (BLP) ranges of the LFP frequencies were anticorrelated in the absence of any explicit stimuli. Beyond the high LFP-BLP signal being correlated with BOLD activity at the recording site, the high and low LFP-BLP envelopes were shown to be significantly correlated with spontaneous BOLD activity recorded from positively and negatively connected prefrontal network regions, respectively. The results suggest that complementary changes in low and high frequency bands may be an intrinsic property of LFPs, that local prefrontal cortical activity is related to spontaneous BOLD fluctuations, and further, that LFP-BLPs may be correlated at a network level.
自发脑活动在脑结构和状态中普遍存在。确定这些代谢成本高昂的内在事件的作用对于理解支配认知和行为的大脑基本生理原理可能至关重要。迄今为止，大多数关于大规模波动及其耦合的研究都是使用脑电图或脑磁图进行的，这些方法在空间分辨信号起源的能力方面存在局限性。侵入性的电生理局部场电位（LFP）记录在空间范围上有限，并且将该方法与功能成像相结合的研究主要局限于感觉/运动区域，几乎没有依据将研究结果外推到进化上更新的前额叶皮质区域。在此，我们在7T磁场下对两只麻醉的猕猴（食蟹猴）采集了自发功能磁共振成像（fMRI）数据，并同时记录了双侧前额叶皮质（9/46d区）的皮质内LFP。在没有任何明确刺激的情况下，LFP频率的高（β-低γ）和低（δ-θ）带限功率（BLP）范围呈负相关。除了高LFP-BLP信号与记录部位的血氧水平依赖（BOLD）活动相关外，高和低LFP-BLP包络分别与从前额叶正性和负性连接网络区域记录的自发BOLD活动显著相关。结果表明，低频和高频带的互补变化可能是LFP的固有特性，局部前额叶皮质活动与自发BOLD波动有关，此外，LFP-BLP可能在网络水平上相关。
