Research ReportElectrophysiological evidence for a neural substrate of morphological rule application in correct wordforms

A critical issue for understanding language processing in the brain is whether linguistic rule application is subserved by a distinct neural substrate. One of the evidence supporting this hypothesis stems from studies employing electroencephalographic measurements during the processing of rule misapplication. This evidence is inconclusive because it might reflect processes caused by the violation such as error handling rather than application of rules per se. Here we provide first evidence that correct regular formations, i.e., German past participles, are associated with left anterior negative-going activity (LAN) providing encephalographic evidence for rule application in the brain during the processing of correct words. Moreover, a LAN response is present regardless of the participles' frequency, suggesting that independently from the mode of lexical access (i.e., decomposition or full-form activation), the cerebral structures associated with rule-based mechanisms are activated.

► First evidence for left anterior negativities (LANs) for correctly inflected words. ► LANs do not merely reflect the processing of grammatical errors. ► LANs are reflections of grammatical rule application per se.► LANs found for forms that could be stored as wholes and do not need rule application. ► Evidence that rule application is independent of full-form storage.