Zhou Xiaoqing Alice, Jiang Yuanyuan, Napadow Vitaly, Yu Xin
Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA.
Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
Brain Sci. 2022 Aug 16;12(8):1085. doi: 10.3390/brainsci12081085.
The locus coeruleus (LC) is one of the most commonly studied brainstem nuclei when investigating brain-behavior associations. The LC serves as a major brainstem relay for both ascending bottom-up and descending top-down projections. Specifically, noradrenergic (NA) LC neurons not only connect globally to higher-order subcortical nuclei and cortex to mediate arousal and attention but also directly project to other brainstem nuclei and to the spinal cord to control autonomic function. Despite the extensive investigation of LC function using electrophysiological recordings and cellular/molecular imaging for both cognitive research and the contribution of LC to different pathological states, the role of neuroimaging to investigate LC function has been restricted. For instance, it remains challenging to identify LC-specific activation with functional MRI (fMRI) in animal models, due to the small size of this nucleus. Here, we discuss the complexity of fMRI applications toward LC activity mapping in mouse brains by highlighting the technological challenges. Further, we introduce a single-vessel fMRI mapping approach to elucidate the vascular specificity of high-resolution fMRI signals coupled to LC activation in the mouse brainstem.
在研究脑-行为关联时，蓝斑核（LC）是最常被研究的脑干核团之一。蓝斑核是上行自下而上和下行自上而下投射的主要脑干中继站。具体而言，去甲肾上腺素能（NA）蓝斑核神经元不仅广泛连接到高阶皮质下核团和皮质以介导觉醒和注意力，还直接投射到其他脑干核团和脊髓以控制自主功能。尽管利用电生理记录以及细胞/分子成像对蓝斑核功能进行了广泛研究，涉及认知研究以及蓝斑核对不同病理状态的影响，但神经成像在研究蓝斑核功能方面的作用一直受到限制。例如，在动物模型中，由于该核团体积小，利用功能磁共振成像（fMRI）识别蓝斑核特异性激活仍然具有挑战性。在此，我们通过强调技术挑战来讨论fMRI应用于小鼠脑内蓝斑核活动图谱绘制的复杂性。此外，我们引入一种单血管fMRI图谱绘制方法，以阐明与小鼠脑干蓝斑核激活相关的高分辨率fMRI信号的血管特异性。
