Neuroscience Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania.
Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania.
J Neurophysiol. 2022 Dec 1;128(6):1421-1434. doi: 10.1152/jn.00043.2022. Epub 2022 Nov 9.
When a complexly structured natural image is presented twice in succession, first as adapter and then as test, neurons in area TE of macaque inferotemporal cortex exhibit repetition suppression, responding less strongly to the second presentation than to the first. This phenomenon, which has been studied primarily in TE, might plausibly be argued to arise in TE because TE neurons respond selectively to complex images and thus carry information adequate for determining whether an image is or is not a repeat. However, the idea has never been put to a direct test. To resolve this issue, we monitored neuronal responses to sequences of complex natural images under identical conditions in areas V2 and TE. We found that repetition suppression occurs in both areas. Moreover, in each area, suppression takes the form of a dynamic alteration whereby the initial peak of excitation is followed by a trough and then a rebound of firing rate. To assess whether repetition suppression in either area is transmitted from the other area, we analyzed the timing of the phenomenon and its degree of spatial generalization. Suppression occurs at shorter latency in V2 than in TE. Therefore it is not simply fed back from TE. Suppression occurs in TE but not in V2 under conditions in which the test and adapter are presented in different visual field quadrants. Therefore it is not simply fed forward from V2. We conclude that repetition suppression occurs independently in V2 and TE. When a complexly structured natural image is presented twice in rapid succession, neurons in inferotemporal area TE exhibit repetition suppression, responding less strongly to the second than to the first presentation. We have explored whether this phenomenon is confined to high-order areas where neurons respond selectively to such images and thus carry information relevant to recognizing a repeat. We have found surprisingly that repetition suppression occurs even in low-order visual area V2.
当一个复杂结构的自然图像连续呈现两次，第一次作为适应刺激，第二次作为测试刺激时，猕猴下颞叶皮层 TE 区的神经元表现出重复抑制，对第二次呈现的反应比第一次弱。这种现象主要在 TE 区研究，可能合理地认为是由于 TE 区神经元对复杂图像有选择性反应，因此携带足以确定图像是否重复的信息。然而，这个想法从未被直接检验过。为了解决这个问题，我们在 V2 和 TE 区相同的条件下监测了对复杂自然图像序列的神经元反应。我们发现，抑制作用发生在两个区域。此外，在每个区域，抑制作用表现为一种动态变化，即初始兴奋峰值之后是一个低谷，然后是发射率的反弹。为了评估两个区域中的任何一个区域的重复抑制是否从另一个区域传递，我们分析了现象的时间和其空间概括程度。抑制作用在 V2 中的潜伏期比 TE 中短。因此，它不是简单地从 TE 反馈回来的。当测试和适应刺激在不同的视野象限呈现时，抑制作用发生在 TE 中，但不在 V2 中。因此，它不是简单地从前馈到 V2。我们得出结论，抑制作用在 V2 和 TE 中独立发生。当一个复杂结构的自然图像快速连续呈现两次时，下颞叶皮层 TE 区的神经元表现出重复抑制，对第二次呈现的反应比第一次弱。我们已经探索了这种现象是否仅限于对这种图像有选择性反应的高级区域，从而携带与识别重复相关的信息。我们惊讶地发现，即使在低阶视觉区 V2 中也会发生重复抑制。
