The N1 sink and P2 source were greater to high than low concentrations of H2S, which is in accord with prior studies (Stuck et al., 2006; Turetsky et al., 2003) and supports their relation to olfactory processing. It is also compatible with the idea the N1 sink reflects N2-like categorization processes, although future studies have to pursue this hypothesis with a more appropriate design, for instance, by including a broader parametric manipulation or different odors. Notably, as the current data were based on 12–16 trials per intensity level, it is evident that viable and meaningful olfactory ERP/CSD averages can be obtained with a relatively small number of trials.
