Processing of sensory information depends on the interactions between hierarchically connected neocortical regions, but it remains unclear how the activity in one area causally influences the activity dynamics in another and how rapidly such interactions change with time. Here, we show that the communication between the primary visual cortex (V1) and high-order visual area LM is context-dependent and surprisingly dynamic over time. By momentarily silencing one area while recording activity in the other, we find that both areas reliably affected changing subpopulations of target neurons within one hundred milliseconds while mice observed a visual stimulus. The influence of LM feedback on V1 responses became even more dynamic when the visual stimuli predicted a reward, causing fast changes in the geometry of V1 population activity and affecting stimulus coding in a context-dependent manner. Therefore, the functional interactions between cortical areas are not static but unfold through rapidly shifting communication subspaces whose dynamics depend on context when processing sensory information.

感觉信息的处理取决于分层连接的新皮层区域之间的相互作用，但目前尚不清楚一个区域的活动如何因果影响另一个区域的活动动态，以及这种相互作用随时间变化的速度。在这里，我们表明初级视觉皮层 (V1) 和高阶视觉区域 LM 之间的交流是依赖于上下文的，并且随着时间的推移是动态的。通过暂时沉默一个区域，同时记录另一个区域的活动，我们发现这两个区域在 100 毫秒内可靠地影响目标神经元的变化亚群，而小鼠则观察到视觉刺激。当视觉刺激预测奖励时，LM 反馈对 V1 反应的影响变得更加动态，导致 V1 种群活动的几何形状发生快速变化，并以上下文相关的方式影响刺激编码。因此，皮层区域之间的功能交互不是静态的，而是通过快速变化的通信子空间展开，其动态取决于处理感觉信息时的上下文。