MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.
MR Center of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.
Neuroimage. 2020 May 1;211:116585. doi: 10.1016/j.neuroimage.2020.116585. Epub 2020 Jan 26.
Despite its importance as the prime method for non-invasive assessment of human brain function, functional MRI (fMRI) was repeatedly challenged with regards to the validity of the fMRI-derived brain activation maps. Amygdala fMRI was particularly targeted, as the amygdala's anatomical position in the ventral brain combined with strong magnetic field inhomogeneities and proximity to large vessels pose considerable obstacles for robust activation mapping. In this high-resolution study performed at ultra-high field (7T) fMRI, we aimed at (1) investigating systematic replicability of amygdala group-level activation in response to an established emotion processing task by varying task instruction and acquisition parameters and (2) testing for intra- and intersession reliability. At group-level, our results show statistically significant activation in bilateral amygdala and fusiform gyrus for each of the runs acquired. In addition, while fusiform gyrus activations are consistent across runs and sessions, amygdala activation levels show habituation effects across runs. This amygdala habituation effect is replicated in a session repeated two weeks later. Varying task instruction between matching emotions and matching persons does not change amygdala activation strength. Also, comparing two acquisition protocols with repetition times of either 700 ms or 1400 ms did not result in statistically significant differences of activation levels. Regarding within-subject reliability of amygdala activation, despite considerable variance in individual habituation patterns, we report fair to good inter-session reliability for the first run and excellent reliability for averages over runs. We conclude that high-resolution fMRI at 7T allows for robust mapping of amygdala activation in a broad range of variations. Our results of amygdala 7T fMRI are suitable to inform methodology and may encourage future studies to continue using emotion discrimination paradigms in clinical and non-clinical applications.
尽管功能磁共振成像（fMRI）作为一种非侵入性评估人类大脑功能的主要方法具有重要意义，但它的 fMRI 衍生脑激活图的有效性却一再受到质疑。杏仁核 fMRI 尤其受到关注，因为杏仁核在大脑腹侧的解剖位置，加上强磁场不均匀性和靠近大血管，给强大的激活映射带来了相当大的障碍。在这项在超高场（7T）fMRI 上进行的高分辨率研究中，我们旨在（1）通过改变任务指令和采集参数，研究杏仁核群体水平激活对已建立的情绪处理任务的系统可重复性，（2）测试内和会话间的可靠性。在群体水平上，我们的结果显示，在每个采集的运行中，双侧杏仁核和梭状回都有统计学意义上的激活。此外，虽然梭状回的激活在运行和会话中是一致的，但杏仁核的激活水平在运行中表现出习惯化效应。这种杏仁核习惯化效应在两周后重复的会议中得到了复制。在匹配情绪和匹配个体之间改变任务指令不会改变杏仁核的激活强度。此外，比较重复时间分别为 700ms 和 1400ms 的两种采集方案，其激活水平也没有统计学上的显著差异。关于杏仁核激活的个体内可靠性，尽管个体习惯化模式存在相当大的差异，但我们报告了第一个运行的良好到良好的会话间可靠性，以及运行间平均值的极好可靠性。我们得出结论，7T 的高分辨率 fMRI 允许在广泛的变化中对杏仁核的激活进行强大的映射。我们的 7T fMRI 杏仁核结果适合为方法学提供信息，并可能鼓励未来的研究继续在临床和非临床应用中使用情绪识别范式。
