title: Electrophysiological correlates of cross-linguistic semantic integration in hearing signers: N400 and LPC.
abstract: We explored semantic integration mechanisms in native and non-native hearing users of sign language and non-signing controls. Event-related brain potentials (ERPs) were recorded while participants performed a semantic decision task for priming lexeme pairs. Pairs were presented either within speech or across speech and sign language. Target-related ERP responses were subjected to principal component analyses (PCA), and neurocognitive basis of semantic integration processes were assessed by analyzing the N400 and the late positive complex (LPC) components in response to spoken (auditory) and signed (visual) antonymic and unrelated targets. Semantically-related effects triggered across modalities would indicate a similar tight interconnection between the signers׳ two languages like that described for spoken language bilinguals. Remarkable structural similarity of the N400 and LPC components with varying group differences between the spoken and signed targets were found. The LPC was the dominant response. The controls׳ LPC differed from the LPC of the two signing groups. It was reduced to the auditory unrelated targets and was less frontal for all the visual targets. The visual LPC was more broadly distributed in native than non-native signers and was left-lateralized for the unrelated targets in the native hearing signers only. Semantic priming effects were found for the auditory N400 in all groups, but only native hearing signers revealed a clear N400 effect to the visual targets. Surprisingly, the non-native signers revealed no semantically-related processing effect to the visual targets reflected in the N400 or the LPC; instead they appeared to rely more on visual post-lexical analyzing stages than native signers. We conclude that native and non-native signers employed different processing strategies to integrate signed and spoken semantic content. It appeared that the signers׳ semantic processing system was affected by group-specific factors like language background and/or usage.
authors.affiliation: Logopedics, P.O. Box 1000, 90014 University of Oulu, Finland; Neurocognitive Unit, P.O. Box 50, 90029 Oulu University Hospital, Finland. Electronic address: swantje.zachau@oulu.fi.
authors.forename: Swantje
authors.initials: S
authors.lastname: Zachau
authors.affiliation: Logopedics, Publicum, Assistentinkatu 7, 20014 University of Turku, Finland. Electronic address: pirjo.korpilahti@utu.fi.
authors.forename: Pirjo
authors.initials: P
authors.lastname: Korpilahti
authors.affiliation: Department of Psychology, P.O. Box 35, 40014 University of Jyväskylä, Finland. Electronic address: jarmo.a.hamalainen@jyu.fi.
authors.forename: Jarmo A
authors.initials: JA
authors.lastname: Hämäläinen
authors.affiliation: Logopedics, P.O. Box 1000, 90014 University of Oulu, Finland; Neurocognitive Unit, P.O. Box 50, 90029 Oulu University Hospital, Finland. Electronic address: leena.ervast@oulu.fi.
authors.forename: Leena
authors.initials: L
authors.lastname: Ervast
authors.affiliation: Logopedics, P.O. Box 1000, 90014 University of Oulu, Finland; Neurocognitive Unit, P.O. Box 50, 90029 Oulu University Hospital, Finland. Electronic address: kaisu.heinanen@oulu.fi.
authors.forename: Kaisu
authors.initials: K
authors.lastname: Heinänen
authors.affiliation: Neurocognitive Unit, P.O. Box 50, 90029 Oulu University Hospital, Finland. Electronic address: vlkalervo.suominen@gmail.com.
authors.forename: Kalervo
authors.initials: K
authors.lastname: Suominen
authors.affiliation: Logopedics, P.O. Box 1000, 90014 University of Oulu, Finland. Electronic address: matti.lehtihalmes@oulu.fi.
authors.forename: Matti
authors.initials: M
authors.lastname: Lehtihalmes
authors.affiliation: Department of Psychology, P.O. Box 35, 40014 University of Jyväskylä, Finland. Electronic address: paavo.ht.leppanen@jyu.fi.
authors.forename: Paavo H T
authors.initials: PH
authors.lastname: Leppänen
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000502:physiology*; D003657:Decision Making / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008037:Linguistics; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology*; D019303:Multilingualism; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D060865:Repetition Priming / Q000502:physiology; D012660:Semantics; D012813:Sign Language; D013067:Speech Perception / Q000502:physiology*
keywords: Late positive complex; N400; Semantic priming; Sign language