PDF(Pubmed)
Abstract：
Flexible responses to sensory stimuli based on changing rules are critical for adapting to a dynamic environment. However, it remains unclear how the brain encodes and uses rule information to guide behavior. Here, we made single-unit recordings while head-fixed mice performed a cross-modal sensory selection task where they switched between two rules: licking in response to tactile stimuli while rejecting visual stimuli, or vice versa. Along a cortical sensorimotor processing stream including the primary (S1) and secondary (S2) somatosensory areas, and the medial (MM) and anterolateral (ALM) motor areas, single-neuron activity distinguished between the two rules both prior to and in response to the tactile stimulus. We hypothesized that neural populations in these areas would show rule-dependent preparatory states, which would shape the subsequent sensory processing and behavior. This hypothesis was supported for the motor cortical areas (MM and ALM) by findings that (1) the current task rule could be decoded from pre-stimulus population activity; (2) neural subspaces containing the population activity differed between the two rules; and (3) optogenetic disruption of pre-stimulus states impaired task performance. Our findings indicate that flexible action selection in response to sensory input can occur via configuration of preparatory states in the motor cortex.
摘要：
基于变化的规则对感官刺激的灵活响应对于适应动态环境至关重要。然而,目前尚不清楚大脑如何编码和使用规则信息来指导行为。这里,我们进行了单单元记录，而头部固定的小鼠执行了跨模态的感觉选择任务，它们在两个规则之间切换：舔响应触觉刺激而拒绝视觉刺激，反之亦然。沿着包括初级（S1）和次级（S2）体感区域的皮层感觉运动处理流，内侧(MM)和前外侧(ALM)运动区，在触觉刺激之前和对触觉刺激的响应中，单神经元活动在两个规则之间进行了区分。我们假设这些区域的神经种群会显示出依赖于规则的预备状态，这将塑造随后的感官加工和行为。运动皮层区域（MM和ALM）的研究结果支持了这一假设：（1）当前任务规则可以从刺激前的种群活动中解码；（2）包含种群活动的神经子空间在两个规则之间有所不同；（3）刺激前状态的光遗传学破坏损害了任务性能。我们的发现表明，响应感觉输入的灵活动作选择可以通过运动皮层中预备状态的配置来进行。
