Journal article
Ionic currents underlying difference in light response between type A and type B photoreceptors
Journal of neurophysiology, Vol.95(5), pp.3060-3072
05/2006
DOI: 10.1152/jn.00780.2005
PMID: 16394075
Abstract
In Hermissenda crassicornis, the memory of light associated with turbulence is stored as changes in intrinsic and synaptic currents in both type A and type B photoreceptors. These photoreceptor types exhibit qualitatively different responses to light and current injection, and these differences shape the spatiotemporal firing patterns that control behavior. Thus the objective of the study was to identify the mechanisms underlying these differences. The approach was to develop a type B model that reproduced characteristics of type B photoreceptors recorded in vitro, and then to create a type A model by modifying a select number of ionic currents. Comparison of type A models with characteristics of type A photoreceptors recorded in vitro revealed that type A and type B photoreceptors have five main differences, three that have been characterized experimentally and two that constitute hypotheses to be tested with experiments in the future. The three differences between type A and type B photoreceptors previously characterized include the inward rectifier current, the fast sodium current, and conductance of calcium-dependent and transient potassium channels. Two additional changes were required to produce a type A photoreceptor model. The very fast firing frequency observed during the first second after light onset required a faster time constant of activation of the delayed rectifier. The fast spike adaptation required a fast, noninactivating calcium-dependent potassium current. Because these differences between type A and type B photoreceptors have not been confirmed in comparative experiments, they constitute hypotheses to be tested with future experiments.
Details
- Title: Subtitle
- Ionic currents underlying difference in light response between type A and type B photoreceptors
- Creators
- K T Blackwell - George Mason University
- Resource Type
- Journal article
- Publication Details
- Journal of neurophysiology, Vol.95(5), pp.3060-3072
- DOI
- 10.1152/jn.00780.2005
- PMID
- 16394075
- NLM abbreviation
- J Neurophysiol
- ISSN
- 0022-3077
- eISSN
- 1522-1598
- Language
- English
- Date published
- 05/2006
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Iowa Neuroscience Institute
- Record Identifier
- 9984446441202771
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