Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117, Berlin, Germany.
Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117, Berlin, Germany.
Neuroimage. 2019 Mar;188:785-793. doi: 10.1016/j.neuroimage.2018.12.036. Epub 2018 Dec 25.
Understanding the organising principles and functional properties of the primate brain's numerous visually responsive cortical regions is one of the major goals in cognitive neuroscience. Functional magnetic resonance imaging (fMRI) studies have revealed that neural responses in higher-order visual cortex are shaped by object categories, task context, and spatiotemporal regularities. Beyond these properties, visual processing in the ventral pathway has been shown to be tightly linked to perceptual awareness, while the evidence regarding dorsal visual processing and awareness is mixed. Most previous studies targeting the dorsal pathway have used dichotomous "visible versus invisible" experimental designs and interocular suppression paradigms to modulate stimulus visibility. In this fMRI study, we sought to investigate category-selective processing of faces and tools in the ventral and dorsal visual streams as a function of parametric stimulus degradation by noise. Both frequentist and Bayesian statistics provide strong evidence for a linear relationship between category-selective processing and stimulus information in both visual pathways. Overall, multivariate category decoding accuracies turned out to be lower in the dorsal pathway. We discuss our results within the context of the emerging notion of highly interconnected visual streams, and provide an outlook on how future studies may help to further refine our understanding of the functional role of the dorsal pathway in visual object processing.
理解灵长类动物大脑中众多对视觉有反应的皮质区域的组织原则和功能特性是认知神经科学的主要目标之一。功能磁共振成像（fMRI）研究表明，高级视觉皮层的神经反应受到物体类别、任务背景和时空规律的影响。除了这些特性之外，腹侧通路中的视觉处理与知觉意识密切相关，而关于背侧视觉处理和意识的证据则存在分歧。大多数以前针对背侧通路的研究都使用了二分法的“可见与不可见”实验设计和双眼抑制范式来调节刺激的可见度。在这项 fMRI 研究中，我们试图研究腹侧和背侧视觉通路上的面孔和工具的类别选择性处理，作为噪声对刺激进行参数化降级的函数。频率论和贝叶斯统计学都为视觉通路上的类别选择性处理与刺激信息之间的线性关系提供了强有力的证据。总的来说，多变量类别解码的准确性在背侧通路中较低。我们在高度互联的视觉流的新兴概念背景下讨论了我们的结果，并展望了未来的研究如何帮助进一步深化我们对背侧通路在视觉物体处理中的功能作用的理解。
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