The Mismatch Negativity (MMN) has recently been found to be sensitive to lexical and grammatical properties. In particular, abstract linguistic categories like phonemes and morphemes seem to be represented in the low level auditory system. We hypothesize a top-down flow of information, that we have called ?language-specific tuning effect?, to explain the sum of data found in different MMN investigations. Our goal is to examine these early effects even for abstract grammatical categories of verbs. In our study we presented German verbal stimuli in a passive oddball paradigm to elicit a MMN in healthy adults (n=10). In condition 1, we used meaningful word stems (imperative) as standards of strong verbs (e.g. /geh/, /sitz/, /lies/) and as deviants the same strong verbs but in the past tense form (e.g. /ging/, /saß/, /las/). In condition 2, the standards were the same as in condition 1 but as deviants we presented different meaningful word stems with the 3rd person singular ending (e.g. /geht/, /sitzt/, /liest/). Preliminary results of the healthy adults will be presented. The long-term aim of the study is to investigate the top-down effect in clinical groups such as children with Specific Language Impairment. These children are assumed to have central-auditory processing deficits that behaviourally manifest themselves in the incorrect use and understanding of grammatical categories.