Krüger G, Kleinschmidt A, Frahm J
Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.
NMR Biomed. 1998 Apr;11(2):75-9. doi: 10.1002/(sici)1099-1492(199804)11:2<75::aid-nbm504>3.0.co;2-7.
Oxygenation-sensitive MRI responses to repetitive and sustained visual activation were compared for stimuli with different temporal, spatial, and luminance contrasts, i.e. reversing checkerboard, flashing diffuse red light, and stationary diffuse gray light with darkness as a control. All paradigms elicited an initial oxygenation 'overshoot' as well as a post-stimulus 'undershoot'. However, whereas flashing and stationary diffuse light resulted in more than a 50% decrease of the initial signal response after 6 min of stimulation, checkerboard responsed remained largely unaffected (less than 20% signal attenuation). The demonstration of a stimulus dependence for sustained visual activation reconciles apparently contradictory reports for stimuli involving checkerboards as opposed to goggles, flickerlight, and movies. It may be caused by stimulus-dependent adjustments of neuronal activity, oxygen consumption, blood flow, or blood volume.
针对具有不同时间、空间和亮度对比度的刺激（即翻转棋盘格、闪烁的漫射红光以及以黑暗为对照的静止漫射灰光），比较了对重复和持续视觉激活的氧合敏感磁共振成像反应。所有范式均引发了初始氧合“过冲”以及刺激后“下冲”。然而，闪烁和静止漫射光在刺激6分钟后导致初始信号反应下降超过50%，而棋盘格反应基本未受影响（信号衰减小于20%）。持续视觉激活的刺激依赖性证明调和了关于涉及棋盘格与护目镜、闪烁光和电影的刺激的明显矛盾报告。这可能是由神经元活动、氧消耗、血流或血容量的刺激依赖性调节引起的。
