Sanganahalli Basavaraju G, Herman Peter, Rothman Douglas L, Blumenfeld Hal, Hyder Fahmeed
Magnetic Resonance Research Center (MRRC), Yale University, New Haven, USA Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, USA Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
Magnetic Resonance Research Center (MRRC), Yale University, New Haven, USA Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, USA Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA.
J Cereb Blood Flow Metab. 2016 Oct;36(10):1695-1707. doi: 10.1177/0271678X16664531. Epub 2016 Aug 25.
Interpretation of regional blood oxygenation level-dependent (BOLD) responses in functional magnetic resonance imaging (fMRI) is contingent on whether local field potential (LFP) and multi-unit activity (MUA) is either dissociated or associated. To examine whether neural-hemodynamic associated and dissociated areas have different metabolic demands, we recorded sensory-evoked responses of BOLD signal, blood flow (CBF), and blood volume (CBV), which with calibrated fMRI provided oxidative metabolism (CMR) from rat's ventral posterolateral thalamic nucleus (VPL) and somatosensory forelimb cortex (S1) and compared these neuroimaging signals to neurophysiological recordings. MUA faithfully recorded evoked latency differences between VPL and S1 because evoked MUA in these regions were similar in magnitude. Since evoked LFP was significantly attenuated in VPL, we extracted the time courses of the weaker thalamic LFP to compare with the stronger cortical LFP using wavelet transform. BOLD and CBV responses were greater in S1 than in VPL, similar to LFP regional differences. CBF and CMR responses were both comparably larger in S1 and VPL. Despite different levels of CBF-CMR and LFP-MUA couplings in VPL and S1, the CMR was well matched with MUA in both regions. These results suggest that neural-hemodynamic associated and dissociated areas in VPL and S1 can have similar metabolic demands.
功能磁共振成像（fMRI）中局部脑血流灌注水平依赖（BOLD）反应的解读取决于局部场电位（LFP）和多单位活动（MUA）是分离还是相关。为了研究神经血流相关和分离区域是否具有不同的代谢需求，我们记录了BOLD信号、血流量（CBF）和血容量（CBV）的感觉诱发反应，通过校准的fMRI从大鼠腹后外侧丘脑核（VPL）和体感前肢皮层（S1）获得氧化代谢（CMR），并将这些神经影像信号与神经生理学记录进行比较。MUA忠实地记录了VPL和S1之间诱发潜伏期的差异，因为这些区域诱发的MUA在幅度上相似。由于VPL中诱发的LFP明显衰减，我们提取了较弱的丘脑LFP的时间进程，使用小波变换与较强的皮层LFP进行比较。S1中的BOLD和CBV反应大于VPL，类似于LFP的区域差异。S1和VPL中的CBF和CMR反应都相对较大。尽管VPL和S1中CBF-CMR和LFP-MUA耦合水平不同，但两个区域的CMR与MUA都匹配良好。这些结果表明，VPL和S1中神经血流相关和分离区域可能具有相似的代谢需求。
