Behavioral and Brain Functions

Background: If all available acoustic phonetic information of words is used during lexical access and consequently stored in the mental lexicon, then all pseudowords that deviate in a single acoustic feature from a word should hamper word recognition. By contrast, models assuming underspecification of redundant phonological information in the mental lexicon predict a differential disruption of word recognition dependent on the phonological structure of the pseudoword. Using neurophysiological measures, the present study tested the predicted asymmetric disruption by assuming that coronal place of articulation for consonants is redundant. Methods: Event-related potentials (ERPs) were recorded during a lexical decision task. The focus of interest was on word medial consonants. The crucial pseudowords were created by replacing the place of articulation of the medial consonant in German disyllabic words. We analyzed the differential temporal characteristics of the N400 pseudoword effect. Results: N400 amplitudes for pseudowords were enhanced compared to words. As the uniqueness and deviation points differ for coronal and non-coronal items, the ERPs had to be correspondingly adjusted. The adjusted ERPs revealed that the N400 pseudoword effect starts earlier for coronal than for non-coronal pseudoword variants. Thus, non-coronal variants are accepted as words longer than the coronal variants. Conclusion: Our results indicate that lexical representations of words containing medial coronal consonants are initially activated by their corresponding non-coronal pseudowords. The most plausible explanation for the asymmetric neuronal processing of coronal and non-coronal pseudoword variants is an underspecified coronal place of articulation in the mental lexicon. Background Despite the fact that we perceive speech in an apparently involuntary fashion, one requires several processing stages to extract the meaning of an utterance. Acousticphonetic features that build up the signal have to be extracted and mapped onto knowledge stored in the listeners' long-term memory in the form of lexical representations [1]. Mental representations must be capable of successfully handling the tremendous amount of variability in the speech signal with which the recognition system is confronted. A frequent source of variation is assimilation where segments take on the properties of other sounds in close proximity. A common assimilation discussed frequently in the literature involves consonants Published: 24 October 2006 Behavioral and Brain Functions 2006, 2:36 doi:10.1186/1744-9081-2-36 Received: 17 August 2006 Accepted: 24 October 2006 This article is available from: http://www.behavioralandbrainfunctions.com/content/2/1/36 © 2006 Friedrich et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.