Lanfranchi Frank F, Wekselblatt Joseph, Wagenaar Daniel A, Tsao Doris Y
Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
Division of Biology and Biological Engineering and Computation and Neural Systems, Caltech, Pasadena, CA, USA.
Nature. 2025 Aug 27. doi: 10.1038/s41586-025-09441-w.
Our knowledge of the brain processes that govern vision is largely derived from studying primates, whose hierarchically organized visual system inspired the architecture of deep neural networks. This raises questions about the universality of such hierarchical structures. Here we examined the large-scale functional organization for vision in one of the closest living relatives to primates, the tree shrew. We performed Neuropixels recordings across many cortical and thalamic areas spanning the tree shrew ventral visual system while presenting a large battery of visual stimuli in awake tree shrews. We found that receptive field size, response latency and selectivity for naturalistic textures, compared with spectrally matched noise, all increased moving anteriorly along the tree shrew visual pathway, consistent with a primate-like hierarchical organization. However, tree shrew area V2 already harboured a high-level representation of complex objects. First, V2 encoded a complete representation of a high-level object space. Second, V2 activity supported the most accurate object decoding and reconstruction among all tree shrew visual areas. In fact, object decoding accuracy from tree shrew V2 was comparable to that in macaque posterior IT and substantially higher than that in macaque V2. Finally, starting in V2, we found strongly face-selective cells resembling those reported in macaque inferotemporal cortex. Overall, these findings show how core computational principles of visual form processing found in primates are conserved, yet hierarchically compressed, in a small but highly visual mammal.
我们对支配视觉的大脑过程的了解很大程度上来自对灵长类动物的研究,其层次结构的视觉系统启发了深度神经网络的架构。这引发了关于这种层次结构普遍性的问题。在这里,我们研究了与灵长类动物关系最近的现存近亲之一——树鼩的视觉大规模功能组织。我们在清醒的树鼩身上呈现大量视觉刺激时,对跨越树鼩腹侧视觉系统的许多皮质和丘脑区域进行了神经像素记录。我们发现,与光谱匹配的噪声相比,感受野大小、反应潜伏期以及对自然纹理的选择性,在沿着树鼩视觉通路向前移动时都增加了,这与类似灵长类动物的层次组织一致。然而,树鼩的V2区域已经包含了复杂物体的高级表征。首先,V2区域编码了一个完整的高级物体空间表征。其次,V2区域的活动在所有树鼩视觉区域中支持最准确的物体解码和重建。事实上,从树鼩V2区域进行的物体解码准确性与猕猴颞下叶后部相当,且远高于猕猴V2区域。最后,从V2区域开始,我们发现了与猕猴颞下皮质中报道的类似的强面部选择性细胞。总体而言,这些发现表明,在灵长类动物中发现的视觉形式处理的核心计算原则在一种小型但视觉高度发达的哺乳动物中是如何被保留且层次压缩的。