Macknik S L, Livingstone M S
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Nat Neurosci. 1998 Jun;1(2):144-9. doi: 10.1038/393.
A brief visual target stimulus may be rendered invisible if it is immediately preceded or followed by another stimulus. This class of illusions, known as visual masking, may allow insights into the neural mechanisms that underlie visual perception. We have therefore explored the temporal characteristics of masking illusions in humans, and compared them with corresponding neuronal responses in the primary visual cortex of awake and anesthetized monkeys. Stimulus parameters that in humans produce forward masking (in which the mask precedes the target) suppress the transient on-response to the target in monkey visual cortex. Those that produce backward masking (in which the mask comes after the target) inhibit the transient after-discharge, the excitatory response that occurs just after the disappearance of the target. These results suggest that, for targets that can be masked (those of short duration), the transient neuronal responses associated with onset and turning off of the target may be important in its visibility.
如果一个短暂的视觉目标刺激在其之前或之后紧接着出现另一个刺激，那么它可能会变得不可见。这类被称为视觉掩蔽的错觉现象，或许能让我们深入了解视觉感知背后的神经机制。因此，我们探究了人类中掩蔽错觉的时间特性，并将其与清醒和麻醉状态下猴子初级视觉皮层中的相应神经元反应进行了比较。在人类中产生前向掩蔽（掩蔽刺激先于目标刺激出现）的刺激参数，会抑制猴子视觉皮层中对目标刺激的瞬态起始反应。而那些产生后向掩蔽（掩蔽刺激在目标刺激之后出现）的刺激参数，则会抑制瞬态后放电，即目标刺激消失后立即出现的兴奋性反应。这些结果表明，对于那些可被掩蔽的目标（持续时间较短的目标），与目标刺激的起始和消失相关的瞬态神经元反应，可能对其可见性起着重要作用。
