Department of Psychiatry & Clinical Psychobiology, Faculty of Psychology, Institute for Brain, Cognition and Behavior (IR3C), University of Barcelona, P. Vall d'Hebron 171, 08035, Barcelona, Spain.
Brain Topogr. 2010 Sep;23(3):301-10. doi: 10.1007/s10548-010-0141-2. Epub 2010 Mar 25.
Although auditory information is processed in several subcortical nuclei, most fMRI studies focus solely on the auditory cortex and do not take brainstem responses into account. One common difficulty in obtaining clear functional brainstem recordings is due to heartbeat related motion, manifested in the rostro-caudal and in the ventro-dorsal directions in the contraction phase of the heart. The aim of this study was to investigate the effect of slice orientation on auditory functional magnetic resonance imagining (fMRI) measurements with respect to the pattern of brainstem oscillation. Fourteen healthy volunteers listened monaurally to modulated pink noise. Blood oxygenation level dependent (BOLD) contrast was performed with an echo-planar image (EPI) sequence using a 3T MRI system. Three different slice orientations were compared: approximately parallel, at 45 degrees , and orthogonal to the brainstem. The standard deviation of the residuals, the effect size, the median t-values, and the number of activated voxels were calculated to quantify variability in activation between orientations. The data for the inferior colliculi indicated that a slice orientation with a 45 degrees angle to the brainstem yielded the lowest sensitivity to motion (reflected in the standard deviation of the residuals). By contrast, the results did not suggest differences between the three imaging planes on the scanning of the auditory cortex. Findings indicate that the 45 degrees slice orientation is the optimum orientation for accurate measurement at the upper brainstem level.
虽然听觉信息在几个皮质下核中被处理，但大多数 fMRI 研究仅关注听觉皮层，而不考虑脑干反应。在获得清晰的功能性脑干记录时，一个常见的困难是由于与心跳相关的运动，在心脏收缩期表现为头尾部和腹尾部的运动。本研究的目的是调查切片方向对听觉功能磁共振成像（fMRI）测量的影响，以及脑干振荡的模式。14 名健康志愿者单耳听调制的粉红噪声。使用 3T MRI 系统，通过回波平面成像（EPI）序列进行血氧水平依赖（BOLD）对比。比较了三种不同的切片方向：与脑干大致平行、45 度和与脑干正交。计算残差标准差、效应大小、中位数 t 值和激活体素数，以量化方向间激活的可变性。下丘的数据表明，与脑干成 45 度角的切片方向对运动的敏感性最低（反映在残差标准差中）。相比之下，这三种成像平面在扫描听觉皮层时并没有显示出差异。研究结果表明，45 度切片方向是准确测量上脑干水平的最佳方向。
