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A model of CA2+ channel opening in response to action potential widening
Title
A model of CA2+ channel opening in response to action potential widening.
Creator
Tranquil, Elizabeth, Rowan, Matthew, Christie, Jason
Date Issued
2013-04-05
PURL
http://purl.flvc.org/fcla/dt/3361215
Subject Headings
Calcium channels, Action Potentials
Format
Document (PDF)
RESPONSES OF A CALCIUM CHANNEL MODELTO VARIATIONS IN VOLTAGE WAVEFORM
Title
RESPONSES OF A CALCIUM CHANNEL MODELTO VARIATIONS IN VOLTAGE WAVEFORM.
Creator
Tranquil, Elizabeth, Christie, Jason, Kirchman, Paul, Kundalkar, Shree, Harriet L. Wilkes Honors College
Abstract/Description
Action potential repolarization in certain neurons slows at neurotransmitter release sites in the axon if an action potential is preceded by sufficient depolarization. We hypothesize that slower repolarization allows axons to change strength of neurotransmission by changing calcium channel open probability. This was explored with a Markov model comprised of multiple calcium channel subtypes and an action potential waveform input. The model was solved for channel open probability, channel...
Show moreAction potential repolarization in certain neurons slows at neurotransmitter release sites in the axon if an action potential is preceded by sufficient depolarization. We hypothesize that slower repolarization allows axons to change strength of neurotransmission by changing calcium channel open probability. This was explored with a Markov model comprised of multiple calcium channel subtypes and an action potential waveform input. The model was solved for channel open probability, channel ionic current and charge from ionic current. The outputted charge from the model was compared to experimental calcium imaging results in neurons from mouse cerebellum. The results show that more calcium flows into the cell when the action potential is widened. This implies that in some neurons, a wider action potential may lead to opening of calcium channels that respond selectively to the duration of the action potential waveform at sites of release.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00003630
Format
Document (PDF)
A DISINHIBITORY MICROCIRCUIT FOR GATED CEREBELLAR LEARNING
Title
A DISINHIBITORY MICROCIRCUIT FOR GATED CEREBELLAR LEARNING.
Creator
Zhang, Ke, Christie, Jason, Dawson-Scully, Ken, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
Performance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to...
Show morePerformance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to alter behavior. Molecular layer interneurons (MLIs) inhibit Purkinje cells to modulate dendritic excitability and action potential output. How MLIs contribute to the regulation and encoding of climbing fiber-evoked adaptive movements remains poorly understood. In this dissertation, I used genetic tools to manipulate the activity of MLIs while monitoring Purkinje cell dendritic activity during a cerebellum-dependent motor learning task with different contexts to evaluate how MLIs are involved in this process. The results show that by suppressing dendritic Ca2+ signals in Purkinje cells, MLI activity coincident with climbing fiber-mediated excitation prevents the occurrence of learning when adaptation is not necessary. On the other hand, with error signals present, disinhibition onto Purkinje cells, mediated by MLI-MLI microcircuit, unlocked the ability of climbing fibers to induce plasticity and motor learning.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013526
Subject Headings
Cerebellum, Interneurons, Purkinje cells, Dendrites, Sensorimotor integration, Neuroplasticity
Format
Document (PDF)