Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, California 90095.
Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095.
J Neurosci. 2022 Apr 27;42(17):3546-3556. doi: 10.1523/JNEUROSCI.1702-21.2022. Epub 2022 Mar 16.
The mouse primary visual cortex is a model system for understanding the relationship between cortical structure, function, and behavior (Seabrook et al., 2017; Chaplin and Margrie, 2020; Hooks and Chen, 2020; Saleem, 2020; Flossmann and Rochefort, 2021). Binocular neurons in V1 are the cellular basis of binocular vision, which is required for predation (Scholl et al., 2013; Hoy et al., 2016; La Chioma et al., 2020; Berson, 2021; Johnson et al., 2021). The normal development of binocular responses, however, has not been systematically measured. Here, we measure tuning properties of neurons to either eye in awake mice of either sex from eye opening to the closure of the critical period. At eye opening, we find an adult-like fraction of neurons responding to the contralateral-eye stimulation, which are selective for orientation and spatial frequency; few neurons respond to ipsilateral eye, and their tuning is immature. Fraction of ipsilateral-eye responses increases rapidly in the first few days after eye opening and more slowly thereafter, reaching adult levels by critical period closure. Tuning of these responses improves with a similar time course. The development and tuning of binocular responses parallel that of ipsilateral-eye responses. Four days after eye opening, monocular neurons respond to a full range of orientations but become more biased to cardinal orientations. Binocular responses, by contrast, lose their cardinal bias with age. Together, these data provide an in-depth accounting of the development of monocular and binocular responses in the binocular region of mouse V1 using a consistent set of visual stimuli and measurements. In this manuscript, we present a full accounting of the emergence and refinement of monocular and binocular receptive field tuning properties of thousands of pyramidal neurons in mouse primary visual cortex. Our data reveal new features of monocular and binocular development that revise current models on the emergence of cortical binocularity. Given the recent interest in visually guided behaviors in mice that require binocular vision (e.g., predation), our measures will provide the basis for studies on the emergence of the neural circuitry guiding these behaviors.
鼠标初级视觉皮层是理解皮层结构、功能和行为之间关系的模型系统（Seabrook 等人，2017；Chaplin 和 Margrie，2020；Hooks 和 Chen，2020；Saleem，2020；Flossmann 和 Rochefort，2021）。V1 中的双眼神经元是双眼视觉的细胞基础，这对于捕食是必需的（Scholl 等人，2013；Hoy 等人，2016；La Chioma 等人，2020；Berson，2021；Johnson 等人，2021）。然而，双眼反应的正常发育尚未得到系统测量。在这里，我们在从睁眼到关键期关闭期间，测量了雄性和雌性清醒小鼠对任一眼的神经元调谐特性。在睁眼时，我们发现了一个类似于成年的对来自对侧眼刺激有反应的神经元比例，这些神经元对方向和空间频率具有选择性；很少有神经元对同侧眼有反应，而且它们的调谐不成熟。在睁眼后最初几天，同侧眼反应的比例迅速增加，此后增加速度较慢，到关键期关闭时达到成年水平。这些反应的调谐具有相似的时间过程。双眼反应的发育和调谐与同侧眼反应的发育和调谐平行。在睁眼后第四天，单眼神经元对全范围的方向有反应，但对主要方向的偏向性更强。相比之下，双眼反应随着年龄的增长失去了主要方向的偏向性。总之，这些数据使用一致的视觉刺激和测量方法，提供了关于小鼠 V1 中双眼区域中单眼和双眼反应发育的深入描述。在本手稿中，我们全面介绍了数千个小鼠初级视觉皮层锥体神经元的单眼和双眼感受野调谐特性的出现和细化。我们的数据揭示了单眼和双眼发育的新特征，这些特征修正了当前关于皮层双眼性出现的模型。鉴于最近对需要双眼视觉的老鼠的视觉引导行为的兴趣（例如捕食），我们的测量结果将为研究引导这些行为的神经回路的出现提供基础。
