Intraspinal microstimulation (ISMS) can effectively activate spinal motor circuits, but the impact on the endogenous respiratory pattern has not been systematically evaluated. Here we delivered ISMS in spontaneously breathing adult rats while simultaneously recording diaphragm and external intercostal electromyography activity. ISMS pulses were delivered from C2-T1 along two rostrocaudal tracts located 0.5 or 1 mm lateral to midline. A tungsten electrode was incrementally advanced from the dorsal spinal surface and 300μs biphasic pulses (10-90 μA) were delivered at depth increments of 600 μm. Dorsal ISMS often produced fractionated inspiratory bursting or caused early termination of the inspiratory effort. Conversely, ventral stimulation had no discernable impact on respiratory resetting. We conclude that ISMS targeting the ventral spinal cord is unlikely to directly alter the respiratory rhythm. Dorsal ISMS, however, may terminate the inspiratory burst through activation of spinobulbar pathways. We suggest that respiratory patterns should be included as an outcome variable in preclinical studies of ISMS.

中文翻译：

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单脉冲脊柱刺激引起的呼吸复位。

脊髓内微刺激（ISMS）可以有效激活脊髓运动回路，但尚未系统评估其对内源性呼吸模式的影响。在这里，我们在自发呼吸的成年大鼠中递送了ISMS，同时记录了diaphragm肌和肋间肌电图的活动。ISMS脉冲是从C2-T1沿着中线外侧0.5或1 mm的两个尾脑尾道传送的。钨电极从背脊表面逐渐推进，并以600μm的深度增量传送300μs双相脉冲（10-90μA）。背侧ISMS经常产生分级的吸气爆发或导致吸气努力的早期终止。相反，腹侧刺激对呼吸复位没有明显影响。我们得出结论，针对腹侧脊髓的ISMS不太可能直接改变呼吸节律。但是，背侧ISMS可能会通过激活脊髓小球通路来终止吸气爆发。我们建议在ISMS临床前研究中应将呼吸模式作为结果变量。