Sources of functional magnetic resonance imaging signal fluctuations in the human brain at rest: a 7 T study.
Sources of functional magnetic resonance imaging signal fluctuations in the human brain at rest: a 7 T study.
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DOI：
10.1016/j.mri.2009.02.004
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发表时间：
2009-10
影响因子：
2.5
通讯作者：
Duyn, Jeff H.
中科院分区：
文献类型：
--
作者：
Bianciardi, Marta;Fukunaga, Masaki;van Gelderen, Peter;Horovitz, Silvina G.;de Zwart, Jacco A.;Shmueli, Karin;Duyn, Jeff H.
功能性磁共振成像（fMRI）中的信号波动可能来自许多来源，这些来源可能具有神经元、生理或仪器来源。为了确定这些来源的相对贡献，我们记录了生理（呼吸和心脏）信号，同时与功能磁共振成像在人类志愿者在休息与他们的眼睛关闭。使用了最先进的技术，包括高磁场（7T）、多通道探测器阵列和高分辨率（3 mm3）回波平面成像（EPI）。我们研究了热噪声和其他来源的方差的相对贡献所观察到的fMRI信号波动在视觉皮层和整个大脑灰质。分别评价了以下方差来源：由于扫描仪不稳定性引起的低频漂移、与呼吸和心动周期相关的影响、由于呼吸流速和心率变异性引起的影响以及暂时归因于自发神经元活动的其他来源。我们发现，低频漂移是fMRI信号波动的最重要来源（3.0%的信号变化在视觉皮层，TE = 32毫秒），其次是自发神经元活动（2.9%），热噪声（2.1%）和由于生理率（呼吸0.9%，心跳0.9%）的变化和与生理周期（0.6%）相关的影响。我们建议选择和使用四个滞后生理噪声回归量作为有效模型来解释与呼吸量变化率和心脏脉动波动相关的方差。我们的研究结果还表明，与全脑灰质相比，视觉皮层对呼吸速率和自发静息状态活动的变化具有更高的敏感性。在本研究的条件下，自发神经元活动是所测量的fMRI信号波动的主要贡献者之一，相对于在3T的类似条件下的早期实验增加了几乎两倍。
Signal fluctuations in functional magnetic resonance imaging (fMRI) can result from a number of sources that may have a neuronal, physiologic, or instrumental origin. To determine the relative contribution of these sources we recorded physiological (respiration and cardiac) signals simultaneously with fMRI in human volunteers at rest with their eyes closed. State-of-the-art technology was used including high magnetic field (7T), a multi-channel detector array, and high resolution (3 mm3) echo-planar imaging (EPI). We investigated the relative contribution of thermal noise and other sources of variance to the observed fMRI signal fluctuations both in the visual cortex and in the whole brain gray matter. The following sources of variance were evaluated separately: low frequency drifts due to scanner instability, effects correlated with respiratory and cardiac cycles, effects due to variability in the respiratory flow rate and cardiac rate, and other sources, tentatively attributed to spontaneous neuronal activity. We found that low-frequency drifts are the most significant source of fMRI signal fluctuations (3.0% signal change in the visual cortex, TE = 32 ms), followed by spontaneous neuronal activity (2.9%), thermal noise (2.1%) and effects due to variability in physiological rates (respiration 0.9%, heartbeat 0.9%) and correlated with physiological cycles (0.6%). We suggest the selection and use of four lagged physiological noise regressors as an effective model to explain the variance related to fluctuations in the rate of respiration volume change and cardiac pulsation. Our results also indicate that, compared to the whole brain gray matter, the visual cortex has higher sensitivity to changes in both the rate of respiration and in the spontaneous resting state activity. Under the conditions of this study, spontaneous neuronal activity is one of the major contributors to the measured fMRI signal fluctuations, increasing almost two-fold relative to earlier experiments under similar conditions at 3T.
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影响因子：
5.7
作者：
Bianciardi M;Fukunaga M;van Gelderen P;Horovitz SG;de Zwart JA;Duyn JH
通讯作者：
Duyn JH
影响因子：
5.7
作者：
Wise, RG;Ide, K;Tracey, I
通讯作者：
Tracey, I
DOI：
10.1098/rstb.2005.1634
发表时间：
2005-05-29
影响因子：
6.3
作者：
Beckmann, CF;DeLuca, M;Smith, SM
通讯作者：
Smith, SM
影响因子：
3.3
作者：
Krüger, G;Glover, GH
通讯作者：
Glover, GH
影响因子：
2.5
作者：
Fukunaga, Masaki;Horovitz, Silvina G.;Duyn, Jeff H.
通讯作者：
Duyn, Jeff H.