Rapid Adaptation to Elevated Extracellular Potassium in the Pyloric Circuit of the Crab, Cancer borealis

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dc.contributor.advisor Marder, Eve
dc.contributor.author He, Lily
dc.date.accessioned 2019-05-24T18:12:38Z
dc.date.available 2019-05-24T18:12:38Z
dc.date.issued 2019
dc.identifier.uri https://hdl.handle.net/10192/36786
dc.description.abstract For decades, elevated potassium ion (K+) concentrations have been used in experiments to increase excitability in neurons and networks, by shifting the potassium equilibrium potential (EK) and consequently, the resting potential. In this study, we studied the effects of increased extracellular [K+] on the well-described pyloric circuit of the crab, Cancer borealis through extracellular recordings recording pyloric network activity and intracellular recordings of the Pyloric Dilator (PD) neuron’s activity. Extracellular recordings revealed concentration-dependent changes in PD neurons’ responses and the variability in the time course and nature of the adaptive responses is closely associated with the time of year. Specifically, a 2.5-fold increase in extracellular [K+] (2.5x[K+]) depolarized PD neurons, led to an unexpected short-term loss of normal bursting activity, and was followed by recovery of spiking and/or bursting activity. In contrast, when pyloric presynaptic inputs to the PD neurons were blocked, PD neurons exhibited no loss of spiking activity in 2.5x[K+]. Over the course of exposure to 2.5x[K+], the action potential threshold in PD neurons decreased in control conditions but remained the same in PD neurons with presynaptic inputs blocked. Additionally, removal of neuromodulatory input did not decrease the robustness of PD neurons’ responses to the perturbation. This study illustrates a case of rapid adaptation to a global perturbation, and the evidence presented underscores the importance of circuit interactions in modulation of the adaptive response.
dc.format.mimetype application/pdf
dc.language English
dc.language.iso eng
dc.publisher Brandeis University
dc.relation.ispartofseries Brandeis University Theses and Dissertations
dc.rights Copyright by Lily He 2019
dc.subject central pattern generator
dc.subject stomatogastric nervous system
dc.subject depolarization block
dc.subject spike threshold
dc.subject F-I curves
dc.subject excitability
dc.title Rapid Adaptation to Elevated Extracellular Potassium in the Pyloric Circuit of the Crab, Cancer borealis
dc.type Thesis
dc.contributor.department Interdepartmental Program in Neuroscience
dc.degree.name MS
dc.degree.level Masters
dc.degree.discipline Neuroscience
dc.degree.grantor Brandeis University, Graduate School of Arts and Sciences


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