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

Abstract

Animals and their neuronal circuits must maintain function despite significant environmental fluctuations. The crab, Cancer borealis, experiences daily changes in ocean temperature and pH. Here, 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 C. 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. Unexpectedly, the stomatogastric ganglion was more sensitive to acid while the cardiac ganglion was more sensitive to base. Considerable 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 ; Temporal 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 different compositions of channel densities—which produce similar pyloric rhythms—are differentially resilient to any given perturbation.…”

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

“…Figures were prepared in Adobe Illustrator CC 2017. All code is available for download at Haley et al (2018) (copy archived at https://github.com/elifesciences-publications/haley_hampton_marder_2018).…”

Motor inactivity in hibernating frogs: Linking plasticity that stabilizes neuronal function to behavior in the natural environment

“…Specifically, animals that encounter challenging environments in their natural habitats (e.g. , large temperature swings, variable pH) are being used to understand how neural systems can maintain performance over a wide range of perturbations (Chen & von Gersdorff, ; Haley, Hampton, & Marder, ; Marder, Haddad, Goeritz, Rosenbaum, & Kispersky, ; Robertson & Money, ; Roemschied, Eberhard, Schleimer, Ronacher, & Schreiber, ; Santin & Hartzler, ; Vallejo, Santin, & Hartzler, ). Along these lines, I propose that motor systems in hibernating animals make useful models to understand how the nervous system keeps itself stable and how these processes integrate into behaviors in a natural setting.…”