Chou Idy W Y, Ban Hiroshi, Chang Dorita H F
Department of Psychology, The University of Hong Kong, Hong Kong.
Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, Japan.
eNeuro. 2021 Jun 17;8(4). doi: 10.1523/ENEURO.0039-21.2021.
Depth sensitivity has been shown to be modulated by object context (plausibility). It is possible that it is behavioural relevance rather than object plausibility per se which drives this effect. Here, we manipulated the biological relevance of objects (face or a non-face) and tested whether object relevance affects behavioural sensitivity and neural responses to depth-position. In a first experiment, we presented human observers with disparity-defined faces and non-faces, and observers were asked to judge the depth position of the target under signal-noise and clear (fine) task conditions. In the second experiment, we concurrently measured behavioural and fMRI responses to depth. We found that behavioural performance varied across stimulus conditions such that they were significantly worse for the upright face than the inverted face and the random shape in the SNR task, but worse for the random shape than the upright face in the feature task. Pattern analysis of fMRI responses revealed that activity of FFA was distinctly different during depth judgments of the upright face versus the other two stimuli, with its responses (and to a stronger extent, those of V3) appearing functionally-relevant to behavioural performance. We speculate that FFA is not only involved in object analysis, but exerts considerable influence on stereoscopic mechanisms as early as in V3 based on a broader appreciation of the stimulus' behavioural relevance.We asked how disparity sensitivity is modulated by object (biological) relevance using behavioural and neuroimaging paradigms. We show that behavioural sensitivity to depth-position changes in biological (face) vs non-biological (random surface) contexts, and that these changes are task-dependent. Imaging results highlight a potentially key role of the fusiform region for governing the modulation of stereo encoding by object relevance. These findings highlight powerful interactions between object recognition mechanisms and stereoencoding, such that the utility of disparity information may be up/down weighed depending on the biological relevance of the object.
深度敏感性已被证明会受到物体背景（合理性）的调节。有可能是行为相关性而非物体本身的合理性驱动了这种效应。在此，我们操纵了物体（面部或非面部）的生物学相关性，并测试物体相关性是否会影响对深度位置的行为敏感性和神经反应。在第一个实验中，我们向人类观察者呈现由视差定义的面部和非面部，并且要求观察者在信号噪声和清晰（精细）任务条件下判断目标的深度位置。在第二个实验中，我们同时测量了对深度的行为和功能磁共振成像反应。我们发现行为表现因刺激条件而异，在信噪比任务中，直立面部的表现明显比倒置面部和随机形状差，但在特征任务中，随机形状的表现比直立面部差。功能磁共振成像反应的模式分析表明，在对直立面部与其他两种刺激进行深度判断期间，梭状回面孔区（FFA）的活动明显不同，其反应（以及在更大程度上，V3的反应）在功能上与行为表现相关。我们推测，FFA不仅参与物体分析，而且基于对刺激行为相关性的更广泛理解，早在V3阶段就对立体视觉机制产生相当大的影响。我们使用行为和神经成像范式来探究视差敏感性是如何由物体（生物学）相关性调节的。我们表明，在生物（面部）与非生物（随机表面）背景下，对深度位置变化的行为敏感性存在差异，并且这些变化取决于任务。成像结果突出了梭状回区域在通过物体相关性控制立体编码调制方面的潜在关键作用。这些发现突出了物体识别机制与立体编码之间强大的相互作用，使得视差信息的效用可能会根据物体的生物学相关性而被上调或下调。
