Reliability of quantal parameter estimates and their changes during long-term potentiation in guinea pig hippocampal slices.

ABSTRACT

Previously we found increases in quantal content (m) and smaller increases in quantal size (v) during long-term potentiation (LTP) in CA1 of hippocampal slices. However, the validity of the deconvolution technique was questioned recently because v estimates correlated with the noise standard deviation (Sn). In computer simulations we show a double-step dependence of v on Sn/v correct v estimates (within +/- 20%) for Sn/v < or = 0.5 and overestimates (correlated with Sn) for Sn/v > 0.5. A novel 'noise addition' procedure is proposed for accepting reliable solutions on the basis of the double-step relationship between v and Sn. Quantal analysis of LTP for more reliable solutions confirmed previous conclusions.