具有相反动态的皮层脊髓神经元亚群汇聚塑造脊髓中间神经元计算
Corticospinal neuron subpopulations with opposing dynamics converge to shape spinal interneuron computations
皮质脊髓神经元(CSN)的激活在协调目标导向动作中起着关键作用,但CSN输出减少这一跨物种保守的特征,其功能作用仍不清楚。通过在执行Go/NoGo杠杆按压任务的小鼠中结合群体成像、投射图谱绘制和建模,我们揭示出具有相反动态(即活动增加或减少)的不同皮质脊髓神经元亚群与熟练运动执行选择性相关。这两种活动特征在CSN的胞体-树突区室中均可观察到,并具有空间组织性:活动增加集中于5B上层,而活动减少则定位于更深的亚区。值得注意的是,单神经元投射图谱绘制显示,相反的CSN信号汇聚到共享的脊髓中间神经元上,而建模表明CSN输出减少驱动了对脊髓中间神经元输入-输出变换的减法调制,从而避免输出饱和并使输出放电频率能够灵活缩放。这些发现重新定义了皮质脊髓功能,表明CSN亚群中输出减少对于在熟练运动执行过程中塑造脊髓计算至关重要。
把群体成像、投射图谱和建模结合,说明皮层脊髓神经元活动下降如何通过减法调制避免脊髓中间神经元输出饱和。
Corticospinal neuron (CSN) activation plays a crucial role in orchestrating goal-directed actions, but the functional role of reduced CSN output, a feature conserved across species, remains unknown. By combining population imaging, projection mapping, and modelling in mice performing a Go/NoGo lever push task, we reveal that distinct corticospinal neuron subpopulations with opposing dynamics (i.e. increased or decreased activity) are selectively associated with skilled movement execution. Both activity profiles are observed throughout CSN somatodendritic compartments and are spatially organized, with increased activity concentrated in upper layer 5B and decreased activity localized to deeper subregions. Notably, single neuron projection mapping revealed that opposing CSN signals converge onto shared spinal interneurons, while modelling showed that reduced CSN output drives subtractive modulation of spinal interneuron input-output transformations, avoiding output saturation and enabling flexible scaling of output firing rates. These findings redefine corticospinal function by demonstrating that reduced output in a subpopulation of CSNs is critical for shaping spinal cord computations during skilled movement execution.
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来源:bioRxiv · Neuroscience · biorxiv.org