Differential modulation of visual object processing in dorsal and ventral stream by stimulus visibility
Differential modulation of visual object processing in dorsal and ventral stream by stimulus visibility
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DOI：
10.1016/j.cortex.2016.07.002
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发表时间：
2016-10-01
期刊：
影响因子：
3.6
通讯作者：
Hesselmann, Guido
中科院分区：
文献类型：
--
作者：
Ludwig, Karin;Sterzer, Philipp;Hesselmann, Guido
作为大脑皮层视觉信息加工的一种功能组织原则，有影响力的两种视觉系统假说提出了背侧“视觉换动作”和腹侧“视觉换感知”的分工。该模型的一个核心假设是，这两个视觉流与视觉知觉密切相关：腹侧视流加工与知觉密切相关，而背侧视流加工与视觉知觉无关。在这项对人类观察者进行的功能磁共振成像(FMRI)研究中，我们直接探测了作为刺激可见度的函数在两个视觉流中的fMRI反应模式中编码的刺激相关信息。在连续闪光抑制(CFS)范式中，我们通过改变面具的对比度来参数调制面部和工具刺激的可见性。我们发现，能见度--由客观和主观措施操作--随着对数CFS面具对比度的增加而成比例地下降。在神经元上，这种关系与腹侧视觉区域密切匹配，显示出与刺激相关的信息随着面罩对比度的增加而线性减少。背侧区域的刺激相关信息也表现出对掩膜对比度的依赖，但这种减少更符合阶跃函数而不是线性函数。总而言之，我们的结果表明，腹侧和背侧的视觉流都与视觉意识有关，但腹侧区域的神经活动比背侧区域更能反映意识的分级差异。(C)2016爱思唯尔有限公司。保留所有权利。
As a functional organization principle in cortical visual information processing, the influential two visual systems' hypothesis proposes a division of labor between a dorsal "vision-for-action" and a ventral "vision-for-perception" stream. A core assumption of this model is that the two visual streams are differentially involved in visual awareness: ventral stream processing is closely linked to awareness while dorsal stream processing is not. In this functional magnetic resonance imaging (fMRI) study with human observers, we directly probed the stimulus-related information encoded in fMRI response patterns in both visual streams as a function of stimulus visibility. We parametrically modulated the visibility of face and tool stimuli by varying the contrasts of the masks in a continuous flash suppression (CFS) paradigm. We found that visibility - operationalized by objective and subjective measures - decreased proportionally with increasing log CFS mask contrast. Neuronally, this relationship was closely matched by ventral visual areas, showing a linear decrease of stimulus-related information with increasing mask contrast. Stimulus-related information in dorsal areas also showed a dependency on mask contrast, but the decrease rather followed a step function instead of a linear function. Together, our results suggest that both the ventral and the dorsal visual stream are linked to visual awareness, but neural activity in ventral areas more closely reflects graded differences in awareness compared to dorsal areas. (C) 2016 Elsevier Ltd. All rights reserved.