Optimizing fluctuation analysis of GABAAergic IPSCs for accurate unitary currents.
Nonstationary fluctuation analysis of synaptic currents requires division of currents into bins of time, with little agreement on how to select an optimal bin width. We used simulated inhibitory postsynaptic currents (simIPSCs) in an empirical approach to establish the optimal bin width needed for estimation of the unitary current, ie. We found acceptable accuracy (< or = 5%) at bin widths shorter than the length of the stationary segment of simIPSCs that persisted when Gaussian noise was added to the simulated currents. We also studied evoked and spontaneous IPSCs mediated by receptors for gamma-aminobutyrate (GABA) in thalamic neurons. Similar to simIPSCs, analysis of the IPSCs yielded saturating relationships between bin width and accuracy of unitary current estimate. Whereas standard error decreased, the accuracy of ie estimates increased with decreasing bin width, forming a plateau at bins below 2-3 ms in duration. Using this approach, one can reliably determine the optimal bin width for nonstationary noise analysis.
Ghavanini
Amer A
AA
Department of Anesthesiology, Pharmacology and Therapeutics, 2176 Health Sciences Mall, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3.
Isbasescu
Ioan M
IM
Mathers
David A
DA
Puil
Ernie
E
D000465:Algorithms; D000704:Analysis of Variance; D000818:Animals; D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D008959:Models, Neurological; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D016011:Normal Distribution; D018408:Patch-Clamp Techniques / Q000379:methods; D011963:Receptors, GABA-A / Q000378:metabolism*; D013788:Thalamus / Q000166:cytology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid