Moradi Farshad, Hipp Constanze, Koch Christof
Computation and Neural Systems Program, California Institute of Technology, Pasadena, CA 91125, USA.
J Cogn Neurosci. 2007 Feb;19(2):331-40. doi: 10.1162/jocn.2007.19.2.331.
We studied the correlation between perception and hemodynamic activity in the visual cortex in a change detection task. Whenever the observer perceived the location of a change, rightly or wrongly, the blood oxygenation level-dependent signal increased in the primary visual cortex and the nearby extrastriate areas above the baseline activity caused by the visual stimulation. This non-sensory-evoked activity was localized and corresponded to the perceived location of the change. When a change was missed, or when observers attended to a different task, the change failed to evoke such a response. The latency of the nonsensory component increased linearly with subjects' reaction time, with a slope of one, and its amplitude was independent of contrast. Control experiments are compatible with the hypothesis that the nonsensory hemodynamic signal is mediated by top-down spatial attention, linked to (but separate from) awareness of the change.
我们在一项变化检测任务中研究了视觉皮层中感知与血流动力学活动之间的相关性。每当观察者正确或错误地感知到变化的位置时，与血液氧合水平相关的信号在初级视觉皮层以及视觉刺激引起的基线活动之上的附近纹外区域中增加。这种非感觉诱发活动是局部性的，并且与感知到的变化位置相对应。当变化被遗漏，或者观察者专注于不同任务时，该变化未能引发这种反应。非感觉成分的潜伏期随受试者的反应时间呈线性增加，斜率为1，其幅度与对比度无关。对照实验与以下假设相符：非感觉血流动力学信号由自上而下的空间注意力介导，与变化的意识相关（但与之分离）。
