Deliz C L Rodríguez, Lee Gerick M, Bushnell Brittany N, Majaj Najib J, Movshon J Anthony, Kiorpes Lynne
Center for Neural Science, New York University, New York, NY, 10003, USA.
Department of Speech, Language, and Hearing Sciences, Moody College of Communication, The University of Texas at Austin, Austin, TX 78712, USA.
bioRxiv. 2025 Jan 27:2025.01.27.634810. doi: 10.1101/2025.01.27.634810.
Visual resolution, contrast sensitivity and form perception improve gradually with age. In nonhuman primates, the sensitivity and resolution of cells in the retina, lateral geniculate nucleus and primary visual cortex (V1) also improve, but not enough to account for the perceptual changes. So, what aspects of visual system development limit visual sensitivity in infants? Improvements in behavioral sensitivity might arise from maturation of regions downstream of V1 such as V2, V4 and IT, which are thought to support increasingly complex perceptual abilities. We recorded the responses of populations of neurons in areas V1, V2, V4, and IT to radial frequency patterns - a type of global form stimulus. Subjects were three young monkeys between the ages of 19 and 54 weeks, and a single adult animal. We found that neurons and neural populations in V4 reliably encoded global form in radial frequency stimuli at the earliest ages we studied, while V1 neurons do not. V2 and IT populations also showed some degree of selectivity for these patterns at early ages, especially at higher radial frequency values. We did not find significant, systematic changes in neural decoding performance that could account for the improvement in behavioral performance over the same age range in an overlapping group of animals (Rodriguez Deliz et al., 2024). Finally, consistent with our prior behavioral results, neural populations in V4 show highest sensitivity for the higher radial frequency values which contain the highest concentration of curvature and orientation cues.
视觉分辨率、对比敏感度和形状感知会随着年龄的增长而逐渐提高。在非人类灵长类动物中，视网膜、外侧膝状体核和初级视觉皮层（V1）中细胞的敏感度和分辨率也会提高，但不足以解释感知上的变化。那么，视觉系统发育的哪些方面限制了婴儿的视觉敏感度呢？行为敏感度的提高可能源于V1下游区域（如V2、V4和IT）的成熟，这些区域被认为支持日益复杂的感知能力。我们记录了V1、V2、V4和IT区域神经元群体对径向频率模式（一种全局形状刺激）的反应。实验对象是三只年龄在19至54周之间的幼猴和一只成年动物。我们发现，在我们研究的最早年龄段，V4中的神经元和神经群体就能可靠地编码径向频率刺激中的全局形状，而V1神经元则不能。V2和IT群体在早期对这些模式也表现出一定程度的选择性，尤其是在较高的径向频率值时。在一组重叠的动物中，我们没有发现神经解码性能有显著的、系统性的变化能够解释在相同年龄范围内行为表现的改善（罗德里格斯·德利兹等人，2024年）。最后，与我们之前的行为结果一致，V4中的神经群体对包含最高曲率和方向线索浓度的较高径向频率值表现出最高的敏感度。
