Department of Anatomical Sciences and Neurobiology, School of Medicine; University of Louisville, Louisville, Kentucky, United States of America.
PLoS Biol. 2023 Apr 21;21(4):e3002096. doi: 10.1371/journal.pbio.3002096. eCollection 2023 Apr.
Abnormal visual experience during a developmental critical period degrades cortical responsiveness. Yet how experience-dependent plasticity alters the response properties of individual neurons and composition of visual circuitry is unclear. Here, we measured with calcium imaging in alert mice how monocular deprivation (MD) during the developmental critical period affects tuning for binocularity, orientation, and spatial frequency for neurons in primary visual cortex. MD of the contralateral eye did not uniformly shift ocular dominance (OD) of neurons towards the fellow ipsilateral eye but reduced the number of monocular contralateral neurons and increased the number of monocular ipsilateral neurons. MD also impaired matching of preferred orientation for binocular neurons and reduced the percentage of neurons responsive at most spatial frequencies for the deprived contralateral eye. Tracking the tuning properties for several hundred neurons before and after MD revealed that the shift in OD is complex and dynamic, with many previously monocular neurons becoming binocular and binocular neurons becoming monocular. Binocular neurons that became monocular were more likely to lose responsiveness to the deprived contralateral eye if they were better matched for orientation prior to deprivation. In addition, the composition of visual circuitry changed as population of neurons more responsive to the deprived eye were exchanged for neurons with tuning properties more similar to the network of responsive neurons altered by MD. Thus, plasticity during the critical period adapts to recent experience by both altering the tuning of responsive neurons and recruiting neurons with matching tuning properties.
在发育关键期出现异常视觉体验会降低皮质反应性。然而，经验依赖性可塑性如何改变单个神经元的反应特性以及视觉回路的组成尚不清楚。在这里，我们通过在清醒小鼠中进行钙成像测量，研究了在发育关键期进行单眼剥夺（MD）如何影响初级视觉皮层中神经元的双眼性、方向和空间频率调谐。对侧眼的 MD 并没有将神经元的眼优势（OD）均匀地向同侧眼转移，而是减少了单侧对侧神经元的数量，增加了单侧同侧神经元的数量。MD 还损害了双眼神经元的最佳取向匹配，并降低了对侧受剥夺眼的大多数空间频率下响应的神经元比例。在 MD 前后跟踪数百个神经元的调谐特性表明，OD 的变化是复杂和动态的，许多以前的单侧神经元变得双眼性，而双眼性神经元变得单侧性。在 MD 之前，如果对定向的匹配更好，那些变得单侧性的双眼神经元更有可能失去对受剥夺的对侧眼的反应能力。此外，随着对受剥夺眼更敏感的神经元群体被具有与 MD 改变的网络更相似的调谐特性的神经元所取代，视觉回路的组成也发生了变化。因此，在关键期内的可塑性通过改变反应神经元的调谐以及招募具有匹配调谐特性的神经元来适应最近的经验。
