Anumba Nmachi, Kelberman Michael A, Pan Wenju, Marriott Alexia, Zhang Xiaodi, Xu Nan, Weinshenker David, Keilholz Shella
Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States.
Department of Human Genetics, Emory University, Atlanta, GA, United States.
Imaging Neurosci (Camb). 2024 Oct 15;2. doi: 10.1162/imag_a_00314. eCollection 2024.
Whole-brain intrinsic activity as detected by resting-state fMRI can besummarized by three primary spatiotemporal patterns. These patterns have beenshown to change with different brain states, especially arousal. Thenoradrenergic locus coeruleus (LC) is a key node in arousal circuits and hasextensive projections throughout the brain, giving it neuromodulatory influenceover the coordinated activity of structurally separated regions. In this study,we used optogenetic-fMRI in rats to investigate the impact of LC stimulation onthe global signal and three primary spatiotemporal patterns. We report small,spatially specific changes in global signal distribution as a result of tonic LCstimulation, as well as regional changes in spatiotemporal patterns of activityat 5 Hz tonic and 15 Hz phasic stimulation. We also found that LC stimulationhad little to no effect on the spatiotemporal patterns detected by complexprincipal component analysis. We hypothesize that localized effects could be dueto engagement of LC modules that support behaviors induced by our specificstimulation parameters, in addition to noradrenergic receptor profiledistributions. Nonetheless, these results show that the effects of LC activityon the BOLD signal in rats may be small and regionally concentrated, as opposedto widespread and globally acting, further supporting emerging evidence of amodular LC.
静息态功能磁共振成像检测到的全脑内在活动可由三种主要的时空模式概括。这些模式已被证明会随着不同的脑状态而变化，尤其是觉醒状态。去甲肾上腺素能蓝斑核（LC）是觉醒回路中的关键节点，在全脑有广泛投射，使其对结构上分离区域的协同活动具有神经调节作用。在本研究中，我们在大鼠中使用光遗传学功能磁共振成像来研究LC刺激对全局信号和三种主要时空模式的影响。我们报告了持续性LC刺激导致的全局信号分布的微小、空间特异性变化，以及在5Hz持续性和15Hz相位性刺激下活动时空模式的区域变化。我们还发现LC刺激对通过复杂主成分分析检测到的时空模式几乎没有影响。我们推测，局部效应可能是由于支持我们特定刺激参数诱导行为的LC模块的参与，以及去甲肾上腺素能受体分布情况。尽管如此，这些结果表明，LC活动对大鼠脑血流动力学信号的影响可能很小且集中在局部，而非广泛且全局作用，这进一步支持了LC模块化的新证据。
