Optically teasing apart neural swelling and depolarization

Abstract We measured birefringence, 90 degree scattered light, and voltage sensitive dye changes from lobster walking leg nerves. Systematic application of key chemical agents revealed separate cellular mechanisms underlying fast optical signals. Each agent exhibited mixed effects, some having a gre...

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Bibliographic Details
Published in:Neuroscience 2007-03, Vol.145 (3), p.887-899
Main Authors: Foust, A.J, Rector, D.M
Format: Article
Language:English
Subjects:
action potential
Animals
Biological and medical sciences
Birefringence
crustacean
Dimethyl Sulfoxide - pharmacology
Evoked Potentials - drug effects
Evoked Potentials - physiology
Extremities - innervation
Fundamental and applied biological sciences. Psychology
Homarus americanus
intrinsic optical imaging
Nephropidae
Neurology
Neurons - drug effects
Neurons - physiology
Ouabain - pharmacology
Tetraethylammonium - pharmacology
Tetrodotoxin - pharmacology
toxin
Vertebrates: nervous system and sense organs
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Summary:Abstract We measured birefringence, 90 degree scattered light, and voltage sensitive dye changes from lobster walking leg nerves. Systematic application of key chemical agents revealed separate cellular mechanisms underlying fast optical signals. Each agent exhibited mixed effects, some having a greater effect on cellular swelling and refractive index, and some altering membrane potential. Birefringence changes were tightly correlated with voltage sensitive dye signals and were perturbed by those agents that altered membrane potential. Signals from light scattered at 90 degrees corroborated the hypothesis that large angle scattering signals arise from changes in the interstitial spaces and were perturbed by those agents that altered cellular swelling and refractive index. We conclude that multiple cellular mechanisms can be exploited to measure rapid optical signals. Since birefringence produces much larger changes than scattering, the use of polarized light might lead to improvements in imaging neural activity with high temporal resolution, especially since birefringence changes corresponded closely to membrane potential.
ISSN:0306-4522
1873-7544
DOI:10.1016/j.neuroscience.2006.12.068