Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Allen Institute for Brain Science, Seattle, Washington, DC, USA.
Function (Oxf). 2020 Jul 2;1(1):zqaa008. doi: 10.1093/function/zqaa008. eCollection 2020.
The brain processes sensory information in a context- and learning-dependent manner for adaptive behavior. Through reward-based learning, relevant sensory stimuli can become linked to execution of specific actions associated with positive outcomes. The neuronal circuits involved in such goal-directed sensory-to-motor transformations remain to be precisely determined. Studying simple learned sensorimotor transformations in head-restrained mice offers the opportunity for detailed measurements of cellular activity during task performance. Here, we trained mice to lick a reward spout in response to a whisker deflection and an auditory tone. Through two-photon calcium imaging of retrogradely labeled neurons, we found that neurons located in primary whisker somatosensory barrel cortex projecting to secondary whisker somatosensory cortex had larger calcium signals than neighboring neurons projecting to primary whisker motor cortex in response to whisker deflection and auditory stimulation, as well as before spontaneous licking. Longitudinal imaging of the same neurons revealed that these projection-specific responses were relatively stable across 3 days. In addition, the activity of neurons projecting to secondary whisker somatosensory cortex was more highly correlated than for neurons projecting to primary whisker motor cortex. The large and correlated activity of neurons projecting to secondary whisker somatosensory cortex might enhance the pathway-specific signaling of important sensory information contributing to task execution. Our data support the hypothesis that communication between primary and secondary somatosensory cortex might be an early critical step in whisker sensory perception. More generally, our data suggest the importance of investigating projection-specific neuronal activity in distinct populations of intermingled excitatory neocortical neurons during task performance.
大脑以依赖上下文和学习的方式处理感觉信息，以实现适应性行为。通过基于奖励的学习，相关的感觉刺激可以与执行与积极结果相关的特定动作相关联。涉及这种目标导向的感觉-运动转换的神经元回路仍有待精确确定。在头部固定的小鼠中研究简单的习得感觉运动转换为在任务执行期间进行细胞活动的详细测量提供了机会。在这里，我们训练小鼠响应胡须偏转和听觉刺激舔奖励喷口。通过逆行标记神经元的双光子钙成像，我们发现，与投射到初级胡须运动皮层的神经元相比，投射到次级胡须体感皮层的初级胡须体感皮层神经元在响应胡须偏转和听觉刺激以及自发舔舐之前具有更大的钙信号。对同一神经元的纵向成像显示，这些投射特异性反应在 3 天内相对稳定。此外，投射到次级胡须体感皮层的神经元的活动比投射到初级胡须运动皮层的神经元的活动相关性更高。投射到次级胡须体感皮层的神经元的大且相关的活动可能增强了对任务执行有贡献的重要感觉信息的通路特异性信号传递。我们的数据支持这样一种假设，即初级和次级体感皮层之间的通信可能是胡须感觉感知的早期关键步骤。更一般地说，我们的数据表明，在任务执行期间，研究不同混合兴奋性新皮层神经元中投射特异性神经元活动的重要性。
