A fundamental question in neuroscience is whether neuronal circuits with variable circuit parameters that produce similar outputs respond comparably to equivalent perturbations.1, 2, 3, 4 Work on the pyloric rhythm of the crustacean stomatogastric ganglion (STG) showed that highly variable sets of intrinsic and synaptic conductances can generate similar circuit activity patterns.5, 6, 7, 8, 9 Importantly, in response to physiologically relevant perturbations, these disparate circuit solutions can respond robustly and reliably,10, 11, 12 but when exposed to extreme perturbations the underlying circuit parameter differences produce diverse patterns of disrupted activity.^7,12,13 In this example, the pyloric circuit is unchanged; only the conductance values vary. In contrast, the gastric mill rhythm in the STG can be generated by distinct circuits when activated by different modulatory neurons and/or neuropeptides.14, 15, 16, 17, 18, 19, 20, 21 Generally, these distinct circuits produce different gastric mill rhythms. However, the rhythms driven by stimulating modulatory commissural neuron 1 (MCN1) and bath-applying CabPK (Cancer borealis pyrokinin) peptide generate comparable output patterns, despite having distinct circuits that use separate cellular and synaptic mechanisms.22, 23, 24, 25 Here, we use these two gastric mill circuits to determine whether such circuits respond comparably when challenged with persisting (hormonal: CCAP) or acute (sensory: GPR neuron) metabotropic influences. Surprisingly, the hormone-mediated action separates these two rhythms despite activating the same ionic current in the same circuit neuron during both rhythms, whereas the sensory neuron evokes comparable responses despite acting via different synapses during each rhythm. These results highlight the need for caution when inferring the circuit response to a perturbation when that circuit is not well defined physiologically.

神经科学中的一个基本问题是，具有可变电路参数的神经元电路是否会产生相似的输出，从而对等效扰动做出类似的响应。1、2、3、4 甲壳动物胃胃神经节 (STG) 幽门节律的研究表明，高度可变的固有和突触电导可以产生类似的电路活动模式。 5, 6, 7, 8, 9 重要的是，为了响应生理相关的扰动，这些不同的电路解决方案可以稳健可靠地响应，10, 11, 12 但是当暴露于极端扰动时潜在的电路参数差异会产生不同模式的中断活动。^{7、12、13 _ _ _ _}在这个例子中，幽门回路没有改变；只有电导值不同。相反，当不同的调节神经元和/或神经肽激活时，STG 中的胃磨节律可以由不同的回路产生。 14、15、16、17、18、19、20、21 通常，这些不同的回路产生不同的胃磨坊节奏。然而，由刺激调节连合神经元 1 (MCN1) 和沐浴 CabPK ( Cancer borealis ) 驱动的节律pyrokinin) 肽产生可比较的输出模式，尽管具有使用单独的细胞和突触机制的不同电路。 22, 23, 24, 25 在这里，我们使用这两个胃磨电路来确定这些电路在受到持续（激素： CCAP）或急性（感觉：GPR 神经元）代谢影响。令人惊讶的是，尽管在两种节律期间激活了同一回路神经元中的相同离子电流，但激素介导的作用将这两种节律分开，而感觉神经元尽管在每个节律期间通过不同的突触起作用，但仍会引起类似的反应。当电路在生理上没有很好地定义时，这些结果强调了在推断电路对扰动的响应时需要谨慎。