Simultaneous BOLD fMRI and fiber-optic calcium recording in rat neocortex
Simultaneous BOLD fMRI and fiber-optic calcium recording in rat neocortex
复制标题
DOI：
10.1038/nmeth.2013
复制
发表时间：
2012-06-01
期刊：
影响因子：
48
通讯作者：
Helmchen, Fritjof
中科院分区：
文献类型：
--
作者：
Schulz, Kristina;Sydekum, Esther;Helmchen, Fritjof
基于血氧水平依赖(BOLD)对比的功能磁共振成像(FMRI)被广泛用于探测大脑活动，但其与潜在神经活动的关系仍然难以捉摸。在这里，我们结合fMRI和荧光钙指示剂信号的光纤记录来研究大鼠躯体感觉皮质中的这种关系。前爪电刺激(1~10 Hz)可诱发神经元来源的快速钙信号，表现出频率依赖性适应。此外，星形胶质细胞特异性染色和双光子显微镜证实，星形胶质细胞网络中出现了较慢的钙信号。在没有明显的胶质细胞激活的情况下，我们可以从同时记录的光纤信号中很好地预测大胆反应，假设有脉冲反应函数，并考虑到神经元的适应。在胶质细胞激活的情况下，我们发现了额外的延长的BOLD信号成分。我们的发现突出了fMRI BOLD信号的复杂性，涉及神经元和神经胶质细胞的活动。结合功能磁共振成像和光纤记录应该有助于阐明BOLD信号背后的细胞机制。
Functional magnetic resonance imaging (fMRI) based on blood oxygen level-dependent (BOLD) contrast is widely used for probing brain activity, but its relationship to underlying neural activity remains elusive. Here, we combined fMRI with fiber-optic recordings of fluorescent calcium indicator signals to investigate this relationship in rat somatosensory cortex. Electrical forepaw stimulation (1-10 Hz) evoked fast calcium signals of neuronal origin that showed frequency-dependent adaptation. Additionally, slower calcium signals occurred in astrocyte networks, as verified by astrocyte-specific staining and two-photon microscopy. Without apparent glia activation, we could predict BOLD responses well from simultaneously recorded fiber-optic signals, assuming an impulse response function and taking into account neuronal adaptation. In cases with glia activation, we uncovered additional prolonged BOLD signal components. Our findings highlight the complexity of fMRI BOLD signals, involving both neuronal and glial activity. Combined fMRI and fiber-optic recordings should help to clarify cellular mechanisms underlying BOLD signals.