Paired turbulence and light do not produce a supralinear calcium increase in Hermissenda

Kim T Blackwell

doi:10.1023/B:JCNS.0000023866.88225.03

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Paired turbulence and light do not produce a supralinear calcium increase in Hermissenda

Journal article

Peer reviewed

Paired turbulence and light do not produce a supralinear calcium increase in Hermissenda

Kim T Blackwell

Journal of computational neuroscience, Vol.17(1), pp.81-99

07/01/2004

DOI: 10.1023/B:JCNS.0000023866.88225.03

PMID: 15218355

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Abstract

The sea slug Hermissenda learns to associate light and hair cell stimulation, but not when the stimuli are temporally uncorrelated. Memory storage, which requires an elevation in calcium, occurs in the photoreceptors, which receive monosynaptic input from hair cells that sense acceleration stimuli such as turbulence. Both light and hair cell activity increase calcium concentration in the photoreceptor, but it is unknown whether paired calcium signals combine supralinearly to initiate memory storage. A correlate of memory storage is an enhancement of the long lasting depolarization (LLD) after light offset, which is attributed to a reduction in voltage dependent potassium currents; however, it is unclear what causes the LLD in the untrained animal. These issues were addressed using a multi-compartmental computer model of phototransduction, calcium dynamics, and ionic currents of the Hermissenda photoreceptor. Simulations of the interaction between light and hair cell activity show that paired stimuli do not produce a greater calcium increase than unpaired stimuli. This suggests that hair cell activity is acting via some other pathway to initiate memory storage. In addition, simulations show that a potassium leak channel, which closes with an increase in calcium, is required to produce both the untrained LLD and the enhanced LLD due to the decrease in voltage dependent potassium currents. Thus, the expression of this correlate of classical conditioning may depend on a leak potassium current.

Animals

Area Under Curve

Calcium - metabolism

Calcium Signaling

Computer Simulation

Dose-Response Relationship, Radiation

gamma-Aminobutyric Acid - pharmacology

Hair Cells, Auditory - physiology

Inositol Polyphosphate 5-Phosphatases

Ion Channel Gating

Ion Channels - physiology

Light

Membrane Potentials - drug effects

Membrane Potentials - radiation effects

Memory - physiology

Models, Biological

Mollusca

Neural Inhibition - drug effects

Neural Inhibition - radiation effects

Nonlinear Dynamics

Patch-Clamp Techniques

Phosphoric Monoester Hydrolases - metabolism

Photic Stimulation

Photoreceptor Cells - drug effects

Photoreceptor Cells - metabolism

Photoreceptor Cells - radiation effects

Photoreceptor Cells, Invertebrate

Potassium - metabolism

Potassium - pharmacology

Potassium Channels - physiology

Time Factors

Vision, Ocular - drug effects

Vision, Ocular - radiation effects

Details

Title: Subtitle: Paired turbulence and light do not produce a supralinear calcium increase in Hermissenda
Creators: Kim T Blackwell - George Mason University
Resource Type: Journal article
Publication Details: Journal of computational neuroscience, Vol.17(1), pp.81-99
DOI: 10.1023/B:JCNS.0000023866.88225.03
PMID: 15218355
NLM abbreviation: J Comput Neurosci
ISSN: 0929-5313
eISSN: 1573-6873
Grant note: K21 MH001141 / NIMH NIH HHS MH01141 / NIMH NIH HHS
Language: English
Date published: 07/01/2004
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Iowa Neuroscience Institute
Record Identifier: 9984446454002771

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