Laboratorium voor Neuro- en Psychofysiologie, KULeuven, Leuven, Belgium.
PLoS One. 2013;8(2):e55340. doi: 10.1371/journal.pone.0055340. Epub 2013 Feb 7.
Neurons in the macaque Anterior Intraparietal area (AIP) encode depth structure in random-dot stimuli defined by gradients of binocular disparity, but the importance of binocular disparity in real-world objects for AIP neurons is unknown. We investigated the effect of binocular disparity on the responses of AIP neurons to images of real-world objects during passive fixation. We presented stereoscopic images of natural and man-made objects in which the disparity information was congruent or incongruent with disparity gradients present in the real-world objects, and images of the same objects where such gradients were absent. Although more than half of the AIP neurons were significantly affected by binocular disparity, the great majority of AIP neurons remained image selective even in the absence of binocular disparity. AIP neurons tended to prefer stimuli in which the depth information derived from binocular disparity was congruent with the depth information signaled by monocular depth cues, indicating that these monocular depth cues have an influence upon AIP neurons. Finally, in contrast to neurons in the inferior temporal cortex, AIP neurons do not represent images of objects in terms of categories such as animate-inanimate, but utilize representations based upon simple shape features including aspect ratio.
猕猴前顶内区（AIP）的神经元对由双眼视差梯度定义的随机点刺激中的深度结构进行编码，但 AIP 神经元对真实世界物体中的双眼视差的重要性尚不清楚。我们研究了双眼视差对 AIP 神经元在被动注视时对真实世界物体图像反应的影响。我们呈现了自然和人为物体的立体图像，其中视差信息与真实世界物体中的视差梯度一致或不一致，以及没有这些梯度的相同物体的图像。尽管超过一半的 AIP 神经元受到双眼视差的显著影响，但绝大多数 AIP 神经元即使在没有双眼视差的情况下仍然保持对图像的选择性。AIP 神经元倾向于更喜欢那些从双眼视差中获得的深度信息与单眼深度线索所发出的深度信息一致的刺激，这表明这些单眼深度线索对 AIP 神经元有影响。最后，与下颞叶皮层的神经元不同，AIP 神经元不是根据有生命/无生命等类别来表示物体的图像，而是利用基于简单形状特征（包括纵横比）的表示。
