Gardumi Anna, Ivanov Dimo, Havlicek Martin, Formisano Elia, Uludağ Kâmil
Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Hum Brain Mapp. 2017 Mar;38(3):1140-1154. doi: 10.1002/hbm.23444. Epub 2016 Oct 28.
A tonotopic organization of the human auditory cortex (AC) has been reliably found by neuroimaging studies. However, a full characterization and parcellation of the AC is still lacking. In this study, we employed pseudo-continuous arterial spin labeling (pCASL) to map tonotopy and voice selective regions using, for the first time, cerebral blood flow (CBF). We demonstrated the feasibility of CBF-based tonotopy and found a good agreement with BOLD signal-based tonotopy, despite the lower contrast-to-noise ratio of CBF. Quantitative perfusion mapping of baseline CBF showed a region of high perfusion centered on Heschl's gyrus and corresponding to the main high-low-high frequency gradients, co-located to the presumed primary auditory core and suggesting baseline CBF as a novel marker for AC parcellation. Furthermore, susceptibility weighted imaging was employed to investigate the tissue specificity of CBF and BOLD signal and the possible venous bias of BOLD-based tonotopy. For BOLD only active voxels, we found a higher percentage of vein contamination than for CBF only active voxels. Taken together, we demonstrated that both baseline and stimulus-induced CBF is an alternative fMRI approach to the standard BOLD signal to study auditory processing and delineate the functional organization of the auditory cortex. Hum Brain Mapp 38:1140-1154, 2017. © 2016 Wiley Periodicals, Inc.
神经影像学研究已确凿发现人类听觉皮层（AC）存在音频拓扑组织。然而，对AC的全面特征描述和分区仍尚缺。在本研究中，我们首次采用伪连续动脉自旋标记（pCASL），利用脑血流量（CBF）来绘制音频拓扑图和语音选择区域。我们证明了基于CBF的音频拓扑的可行性，并且发现尽管CBF的对比噪声比更低，但它与基于血氧水平依赖（BOLD）信号的音频拓扑有良好的一致性。基线CBF的定量灌注图谱显示，以颞横回为中心存在一个高灌注区域，对应主要的高低高频梯度，与假定的初级听觉核心区域重合，这表明基线CBF可作为AC分区的一个新标记。此外，采用了 susceptibility加权成像来研究CBF和BOLD信号的组织特异性以及基于BOLD的音频拓扑可能存在的静脉偏差。对于仅BOLD激活的体素，我们发现其静脉污染百分比高于仅CBF激活的体素。综上所述，我们证明基线和刺激诱发的CBF都是一种替代标准BOLD信号的功能磁共振成像方法，可用于研究听觉处理并描绘听觉皮层的功能组织。《人类大脑图谱》38:1140 - 1154, 2017。© 2016威利期刊公司。
