果蝇转向连接组模型中的局灶性神经元丢失与细胞替换
Focal neuronal loss and cell replacement in a connectome model of fly steering
局灶性神经元丢失后哪些细胞和连接需要恢复,实验上难以确定。作者用连接组约束的果蝇神经系统脉冲模型解码运动神经元输出,模拟视觉引导转向。丢失4000个神经元后,路径直线度随损伤位置在0.04到0.95之间变化;在固定感觉运动位点,2000个神经元的损伤使模拟位移降至完整状态的6.5%。在100次随机模拟中,优先运动控制通路替换100个细胞可恢复到62.5%,随机选100个细胞为10.1%,随机选1000个细胞为48.5%。
Focal neuronal loss after stroke, traumatic brain injury or spinal cord injury can disrupt circuits and result in persistent motor deficits. Which cells and connections must be restored to recover a specific behavior is difficult to establish experimentally. Here we use a connectome-constrained spiking model of the fruit-fly nervous system and decode motor-neuron output to simulate visually guided steering. After loss of 4,000 neurons, path straightness ranged from 0.04 to 0.95 depending on lesion location. At a fixed sensorimotor site, a 2,000-neuron lesion reduced simulated displacement to 6.5% of intact. Across 100 stochastic simulation realizations of the connectome, replacing 100 cells with their original connections increased displacement to 62.5% of intact when motor-control pathways were prioritized, compared with 10.1% after random selection of 100 cells and 48.5% after random selection of 1,000 cells. When connections were instead inferred from cell type, the same 100 intended replacements reached 60.0% of intact with matched identities and 6.7% with non-target identities, indicating that cell identity and type-dependent integration are required for recovery. Our model generates testable predictions for genetic ablation experiments in fruit flies and identifies candidate cellular and circuit requirements for motor repair that can inform cell replacement therapies and future models of mammalian locomotion.
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来源:bioRxiv · Neuroscience · biorxiv.org