Shih Yen-Yu Ian, Huang Shiliang, Chen You-Yin, Lai Hsin-Yi, Kao Yu-Chieh Jill, Du Fang, Hui Edward S, Duong Timothy Q
1] Department of Neurology, University of North Carolina, Chapel Hill, North Carolina, USA [2] Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, North Carolina, USA [3] Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina, USA [4] Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
J Cereb Blood Flow Metab. 2014 Sep;34(9):1483-92. doi: 10.1038/jcbfm.2014.103. Epub 2014 Jun 11.
Negative functional magnetic resonance imaging (fMRI) response in the striatum has been observed in several studies during peripheral sensory stimulation, but its relationship between local field potential (LFP) remains to be elucidated. We performed cerebral blood volume (CBV) fMRI and LFP recordings in normal rats during graded noxious forepaw stimulation at nine stimulus pulse widths. Albeit high LFP-CBV correlation was found in the ipsilateral and contralateral sensory cortices (r=0.89 and 0.95, respectively), the striatal CBV responses were neither positively, nor negatively correlated with LFP (r=0.04), demonstrating that the negative striatal CBV response is not originated from net regional inhibition. To further identify whether this negative CBV response can serve as a marker for striatal functional recovery, two groups of rats (n=5 each) underwent 20- and 45-minute middle cerebral artery occlusion (MCAO) were studied. No CBV response was found in the ipsilateral striatum in both groups immediately after stroke. Improved striatal CBV response was observed on day 28 in the 20-minute MCAO group compared with the 45-minute MCAO group (P<0.05). This study shows that fMRI signals could differ significantly from LFP and that the observed negative CBV response has potential to serve as a marker for striatal functional integrity in rats.
在多项研究中，在外周感觉刺激期间观察到纹状体中存在负性功能磁共振成像（fMRI）反应，但其与局部场电位（LFP）之间的关系仍有待阐明。我们在正常大鼠中，于9种刺激脉冲宽度的分级有害前爪刺激期间进行了脑血容量（CBV）fMRI和LFP记录。尽管在同侧和对侧感觉皮层中发现了较高的LFP-CBV相关性（分别为r = 0.89和0.95），但纹状体CBV反应与LFP既无正相关也无负相关（r = 0.04），这表明纹状体CBV负反应并非源于净区域抑制。为了进一步确定这种CBV负反应是否可作为纹状体功能恢复的标志物，对两组大鼠（每组n = 5）进行了20分钟和45分钟的大脑中动脉闭塞（MCAO）研究。两组大鼠卒中后立即在同侧纹状体中均未发现CBV反应。与45分钟MCAO组相比，20分钟MCAO组在第28天观察到纹状体CBV反应有所改善（P < 0.05）。本研究表明，fMRI信号可能与LFP有显著差异，且观察到的CBV负反应有潜力作为大鼠纹状体功能完整性的标志物。
