Büchel C, Friston K J
Leopold Müller Functional Imaging Laboratory, Wellcome Department of Cognitive Neurology, London, UK.
Hum Brain Mapp. 1998;6(5-6):403-8. doi: 10.1002/(SICI)1097-0193(1998)6:5/6<403::AID-HBM14>3.0.CO;2-9.
Attention to visual motion can increase the responsiveness of the motion-selective cortical area V5 and the posterior parietal cortex. We addressed attentional modulation of effective connectivity using variable parameter regression and functional magnetic resonance imaging. We present data from a single subject scanned under identical stimulus conditions (visual motion) while varying only the attentional component of the task. Variable parameter regression of the influence of V5 on PP revealed increased effective connectivity during attention to visual motion. With this dynamic measure of effective connectivity we were able to make inferences about the source of modulation by looking for regions that predicted the observed changes in connectivity. Using an ordinary regression analysis, we showed that activity in the prefrontal cortex could explain these changes and was sufficient to account for these modulatory influences on connections in the dorsal visual pathway.
对视觉运动的关注可增强运动选择性皮层区域V5和后顶叶皮层的反应性。我们使用可变参数回归和功能磁共振成像来研究有效连接的注意力调制。我们展示了来自一名受试者在相同刺激条件（视觉运动）下扫描的数据，同时仅改变任务的注意力成分。V5对PP影响的可变参数回归显示，在关注视觉运动期间有效连接增加。通过这种有效连接的动态测量，我们能够通过寻找预测观察到的连接变化的区域来推断调制源。使用普通回归分析，我们表明前额叶皮层的活动可以解释这些变化，并且足以解释对背侧视觉通路连接的这些调制影响。
