National Institutes of Health.
J Cogn Neurosci. 1997 Jul;9(4):476-89. doi: 10.1162/jocn.1997.9.4.476.
Visual imagery is the invention or recreation of a perceptual experience in the absence of retinal input.The degree to which the same neural representations are involved in both visual imagery and visual perception is unclear. Previous studies have shown that visual imagery interferes with perception (Perky effect). We report here psychophysical data showing a direct facilitatory effect of visual imagery on visual perception. Using a lateral masking detection paradigm of a Gabor target, flanked by peripheral Gabor masks, observers performed imagery tasks that were preceded by perceptual tasks. We found that both perceived and imaginary flanking masks can reduce contrast detection threshold. At short target-to-mask distances imagery induced a threshold reduction of 50% as compared with perception, while at long target-to-mask distances imagery and perception had similar facilitatory effect. The imagery-induced facilitation was specific to the orientation of the stimulus, as well as to the eye used in the task. These data indicate the existence of a stimulus-specific short-term memory system that stores the sensory trace and enables reactivation of quasi-pictorial representations by topdown processes. We suggest that stimulus parameters dominate the imagery-induced facilitation at short target-to-mask distances, yet the topdown component contributes to the effect at long target-to-mask distances.
视觉意象是在没有视网膜输入的情况下发明或重新创造的感知体验。在视觉意象和视觉感知中涉及相同的神经表示的程度尚不清楚。以前的研究表明，视觉意象会干扰感知（Perky 效应）。我们在这里报告心理物理数据，显示视觉意象对视觉感知有直接的促进作用。使用侧抑制掩蔽检测范式的 Gabor 目标，由外围 Gabor 掩蔽物包围，观察者执行在感知任务之前进行的意象任务。我们发现，无论是感知的还是想象的侧翼掩蔽都可以降低对比度检测阈值。在短的目标到掩蔽距离下，与感知相比，意象诱导的阈值降低了 50%，而在长的目标到掩蔽距离下，意象和感知具有相似的促进作用。意象诱导的促进作用特定于刺激的方向，以及在任务中使用的眼睛。这些数据表明存在一个刺激特异性的短期记忆系统，该系统存储感觉痕迹，并通过自上而下的过程重新激活准图像表示。我们建议，在短的目标到掩蔽距离下，刺激参数主导着意象诱导的促进作用，而自上而下的成分则有助于长的目标到掩蔽距离的作用。
