Activity-dependent refinement of visual circuitry

发育中的神经系统能够通过分子引导信号和活动依赖的连接微调相结合，达到成人大脑中惊人的布线精度。过去关于连接细化的研究大多集中在单个神经元的结构或突触变化及其轴突对突触后树突目标的投射。事实上，要了解神经系统在发育过程中如何优化连接，不仅需要研究单个神经元的活动依赖性重塑，还需要研究神经元群之间对模式活动的反应。

The developing nervous system is able to achieve the remarkable precision of wiring found in the adult brain through a combination of molecular guidance cues and activity-dependent fine-tuning of connections. Much of the research on connection refinement in the past has focused on structural or synaptic changes that occur at the level of individual neurons and their axonal projections onto postsynaptic dendritic targets. In fact, to appreciate how the nervous system optimizes connectivity during development, it is necessary to study not just the activity-dependent remodeling of individual neurons, but rather the interactions between ensembles of neurons in response to patterned activity.