Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA; Center for the Neural Basis of Cognition, 1400 Locust Street, Pittsburgh, PA 15219, USA.
Curr Biol. 2021 Jan 25;31(2):369-380.e5. doi: 10.1016/j.cub.2020.10.046. Epub 2020 Nov 20.
The development of the visual system is known to be shaped by early-life experience. To identify response properties that contribute to enhanced natural scene representation, we performed calcium imaging of excitatory neurons in the primary visual cortex (V1) of awake mice raised in three different conditions (standard-reared, dark-reared, and delayed-visual experience) and compared neuronal responses to natural scene features in relation to simpler grating stimuli that varied in orientation and spatial frequency. We assessed population selectivity in the V1 by using decoding methods and found that natural scene discriminability increased by 75% between the ages of 4 and 6 weeks. Both natural scene and grating discriminability were higher in standard-reared animals than in those raised in the dark. This increase in discriminability was accompanied by a reduction in the number of neurons that responded to low-spatial-frequency gratings. At the same time, there was an increase in neuronal preference for natural scenes. Light exposure restricted to a 2- to 4-week window during adulthood did not induce improvements in natural scene or in grating stimulus discriminability. Our results demonstrate that experience reduces the number of neurons needed to effectively encode grating stimuli and that early visual experience enhances natural scene discriminability by directly increasing responsiveness to natural scene features.
视觉系统的发育被认为是由早期生活经验塑造的。为了确定有助于增强自然场景表示的反应特性，我们对在三种不同条件下（标准饲养、暗饲养和视觉经验延迟）饲养的清醒小鼠的初级视觉皮层（V1）中的兴奋性神经元进行钙成像，并比较了与简单光栅刺激有关的自然场景特征的神经元反应，这些光栅刺激在方向和空间频率上有所变化。我们通过使用解码方法评估了 V1 中的群体选择性，并发现自然场景的可分辨性在 4 到 6 周之间增加了 75%。与在黑暗中饲养的动物相比，标准饲养的动物对自然场景和光栅的可分辨性更高。这种可分辨性的提高伴随着对低空间频率光栅反应的神经元数量的减少。与此同时，神经元对自然场景的偏好增加。在成年期仅限制在 2 到 4 周的时间内进行光照暴露并不能提高自然场景或光栅刺激的可分辨性。我们的结果表明，经验减少了有效编码光栅刺激所需的神经元数量，而早期视觉经验通过直接增加对自然场景特征的反应能力来提高自然场景的可分辨性。
