Optogenetic astrocyte activation evokes BOLD fMRI response with oxygen consumption without neuronal activity modulation
Optogenetic astrocyte activation evokes BOLD fMRI response with oxygen consumption without neuronal activity modulation
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DOI：
10.1002/glia.23454
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发表时间：
2018-05
期刊：
影响因子：
6.2
通讯作者：
N. Takata;Y. Sugiura;Keitaro Yoshida;M. Koizumi;Nishida Hiroshi;Kurara Honda;R. Yano;Yuji Komaki;K. Matsui;M. Suematsu;M. Mimura;H. Okano;Kenji F. Tanaka
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文献类型：
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作者：
N. Takata;Y. Sugiura;Keitaro Yoshida;M. Koizumi;Nishida Hiroshi;Kurara Honda;R. Yano;Yuji Komaki;K. Matsui;M. Suematsu;M. Mimura;H. Okano;Kenji F. Tanaka
基于血氧水平依赖性（BOLD）信号的功能磁共振成像（fMRI）已被用于推断大脑中神经元激活的位置。然而，最近的一项研究表明，在没有神经元兴奋的情况下，BOLD信号的产生出乎意料，这使我们假设BOLD信号产生的另一个细胞来源的存在。星形胶质细胞或神经元的光遗传学激活的集体评估，清醒小鼠的功能磁共振成像，电生理测量和神经元激活的组织化学检测，一致表明星形胶质细胞是另一个细胞来源。出乎意料的是，星形胶质细胞诱发的BOLD信号伴随着氧气消耗而不调节神经元活动。脑切片的成像质谱分析发现，乙酰-肉碱的合成是通过星形胶质细胞部位的氧化葡萄糖代谢进行的，而不是神经元诱发的BOLD信号。我们的数据提供了因果证据，表明星形细胞激活本身能够引起BOLD信号反应，这可能会导致重新考虑当前将BOLD信号作为神经元激活标志的解释。
Functional magnetic resonance imaging (fMRI) based on the blood oxygenation level‐dependent (BOLD) signal has been used to infer sites of neuronal activation in the brain. A recent study demonstrated, however, unexpected BOLD signal generation without neuronal excitation, which led us to hypothesize the presence of another cellular source for BOLD signal generation. Collective assessment of optogenetic activation of astrocytes or neurons, fMRI in awake mice, electrophysiological measurements, and histochemical detection of neuronal activation, coherently suggested astrocytes as another cellular source. Unexpectedly, astrocyte‐evoked BOLD signal accompanied oxygen consumption without modulation of neuronal activity. Imaging mass spectrometry of brain sections identified synthesis of acetyl‐carnitine via oxidative glucose metabolism at the site of astrocyte‐, but not neuron‐evoked BOLD signal. Our data provide causal evidence that astrocytic activation alone is able to evoke BOLD signal response, which may lead to reconsideration of current interpretation of BOLD signal as a marker of neuronal activation.