<qa>  What is the TMS determination of MEP amplitude?Design. Normal volunteers accepted into the study will be subjected to the following exams: a TMS determination of MEP amplitude and paired-pulse testing at baseline and at peak serum levels after drug or placebo administration, b digital EEG recording for 1 h at baseline before administration of drug or placebo and during a period of 3 h after administration. Samples for serum chemistry, liver function tests, hematology, and urinalysis will be obtained at admission, at discharge, and in every clinic visit during the study. Blood samples for determining serum talampanel levels will be obtained at 1, 2, 3, and 8 h after drug administration. MEPs at interstimulus intervals of 2 to 20 ms will be compared among subjects before and after drug administration, by a repeated measures analysis of variance. Talampanel levels will be correlated with MEP amplitudes by regression analysis. 