Two central pattern generators from the crab, Cancer borealis, respond robustly and differentially to extreme extracellular pH

Abstract

The activity of neuronal circuits depends on the properties of the constituent neurons and their underlying synaptic and intrinsic currents. We describe the effects of extreme changes in extracellular pH – from pH 5.5 to 10.4 – on two central pattern generating networks, the stomatogastric and cardiac ganglia of the crab, Cancer borealis. Given that the physiological properties of ion channels are known to be sensitive to pH within the range tested, it is surprising that these rhythms generally remained robust from pH 6.1 to pH 8.8. The pH sensitivity of these rhythms was highly variable between animals and, unexpectedly, between ganglia. Animal-to-animal variability was likely a consequence of similar network performance arising from variable sets of underlying conductances. Together, these results illustrate the potential difficulty in generalizing the effects of environmental perturbation across circuits, even within the same animal.

Temperature compensation in a small rhythmic circuit

“…Temperature is not the only perturbation that crabs and lobsters experience. As with temperature, the responses of the STG to changes in pH are diverse across individuals (Haley et al, 2018), again consistent with the large amount of animal-to-animal variability in the expression of ion channels (Schulz et al, 2006(Schulz et al, , 2007Temporal et al, 2014;Tran et al, 2019). It is therefore reasonable to assume that the responses to a global perturbation are diverse across individuals because di↵erent compositions of channel densities-which produce similar pyloric rhythms-are di↵erentially resilient to any given perturbation.…”

Coupling between fast and slow oscillator circuits in Cancer borealis is temperature-compensated

“…The coordination of oscillatory circuits, often with distinct temporal features, is therefore key to circuit function and information processing. Because fluctuations in a circuit’s environment can impact function ( Fonseca and Correia, 2007 ; Tang et al, 2010 ; Haddad and Marder, 2018 ; Haley et al, 2018 ; Kushinsky et al, 2019 ; He et al, 2020 ), it is important to know how robust this coordination is to externally or internally generated perturbations.…”

Coupling between fast and slow oscillator circuits inCancer borealisis temperature compensated

“…The coordination of oscillatory circuits, often with distinct temporal features, is therefore key to circuit function and information processing. Because fluctuations in a circuit’s environment can impact function (Fonseca and Correia, 2007; Tang et al, 2010; Haddad and Marder, 2018; Haley et al, 2018; Kushinsky et al, 2019; He et al, 2020), it is important to know how robust this coordination is to externally or internally generated perturbations.…”