Kosslyn S M, Thompson W L, Kim I J, Alpert N M
Department of Psychology, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature. 1995 Nov 30;378(6556):496-8. doi: 10.1038/378496a0.
We report here the use of positron emission tomography (PET) to reveal that the primary visual cortex is activated when subjects close their eyes and visualize objects. The size of the image is systematically related to the location of maximal activity, which is as expected because the earliest visual areas are spatially organized. These results were only evident, however, when imagery conditions were compared to a non-imagery baseline in which the same auditory cues were presented (and hence the stimuli were controlled); when a resting baseline was used (and hence brain activation was uncontrolled), imagery activation was obscured because of activation in visual cortex during the baseline condition. These findings resolve a debate in the literature about whether imagery activates early visual cortex and indicate that visual mental imagery involves 'depictive' representations, not solely language-like descriptions. Moreover, the fact that stored visual information can affect processing in even the earliest visual areas suggests that knowledge can fundamentally bias what one sees.
我们在此报告正电子发射断层扫描（PET）的应用，以揭示当受试者闭上眼睛并想象物体时，初级视觉皮层会被激活。图像的大小与最大活动的位置系统相关，这正如预期的那样，因为最早的视觉区域是按空间组织的。然而，只有当将想象条件与呈现相同听觉线索的非想象基线（从而控制了刺激）进行比较时，这些结果才明显；当使用静息基线（从而大脑激活未得到控制）时，由于基线条件下视觉皮层的激活，想象激活被掩盖了。这些发现解决了文献中关于想象是否激活早期视觉皮层的争论，并表明视觉心理意象涉及“描绘性”表征，而不仅仅是类似语言的描述。此外，存储的视觉信息甚至可以影响最早视觉区域的处理这一事实表明，知识可以从根本上影响一个人的所见。
