Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
Curr Biol. 2020 Dec 7;30(23):4682-4692.e7. doi: 10.1016/j.cub.2020.09.015. Epub 2020 Oct 8.
Cortical parallel processing streams segregate many diverse features of a sensory scene. However, some features are distributed across streams, begging the question of whether and how such distributed representations contribute to perception. We determined the necessity of the primary visual cortex (V1) and three key higher visual areas (lateromedial [LM], anterolateral [AL], and posteromedial [PM]) for perception of orientation and contrast, two features that are robustly encoded across all four areas. Suppressing V1, LM, or AL decreased sensitivity for both orientation discrimination and contrast detection, consistent with a role for these areas in sensory perception. In comparison, suppressing PM selectively increased false alarm (FA) rates during contrast detection, without any effect on orientation discrimination. This effect was not retinotopically specific, suggesting that suppression of PM altered sensory integration or the decision-making process rather than processing of local visual features. Thus, we find that distributed representations in the visual system can nonetheless support specialized perceptual roles for higher visual cortical areas.
皮层平行处理流将感觉场景的许多不同特征分离。然而，有些特征分布在流中，这就提出了一个问题，即这种分布式表示形式是否以及如何有助于感知。我们确定了初级视觉皮层（V1）和三个关键的高级视觉区域（后外侧[LM]、前外侧[AL]和后内侧[PM]）对于感知方向和对比度的必要性，这两个特征在所有四个区域都得到了强有力的编码。抑制 V1、LM 或 AL 会降低方向辨别和对比度检测的敏感性，这与这些区域在感觉感知中的作用一致。相比之下，抑制 PM 选择性地增加了对比度检测时的假警报（FA）率，而对方向辨别没有影响。这种效果不是视网膜特异性的，这表明 PM 的抑制改变了感觉整合或决策过程，而不是局部视觉特征的处理。因此，我们发现视觉系统中的分布式表示形式仍然可以支持高级视觉皮层区域的专门感知作用。
