Convergent Rhythm Generation from Divergent Cellular Mechanisms

摘要: Different modulatory inputs commonly elicit distinct rhythmic motor patterns from a central pattern generator (CPG), but they can instead the same pattern. We are determining rhythm-generating mechanisms in this latter situation, using gastric mill (chewing) CPG crab (Cancer borealis) stomatogastric ganglion, where stimulating projection neuron MCN1 (modulatory commissural 1) or bath applying CabPK (C. borealis pyrokinin) peptide elicits pattern, despite configuring different circuits. In both cases, core rhythm includes reciprocally inhibitory neurons LG (lateral gastric) and Int1 (interneuron 1), pyloric (food-filtering) circuit pacemaker AB (anterior burster) is additionally necessary only for generation. drives by activating modulator-activated inward current (IMI), which waxes wanes periodically due to phasic feedback inhibition of transmitter release. Each buildup IMI enables generate self-terminating burst thereby alternate with activity. Here we establish that generation plus slowly transient, low-threshold (ITrans-LTS) voltage, time, Ca2+ dependent. Unlike MCN1, maintains steady activation, causing subthreshold depolarization facilitates periodic postinhibitory rebound caused regular decay availability ITrans-LTS. Thus, use drive neuronal rhythm. Additionally, ionic (IMI) play roles under these conditions, while currents (IMI, ITrans-LTS) role.