Spatiotemporal dynamics of sentence processing: are distinct neural populations
responsible for morphological and morphosyntactic parsing?
Alina Leminen*, Sini Jakonen*, Miika Leminen*, Jyrki P. Mäkelä**, Minna Lehtonen*
* Cognitive Brain Research Unit, Cognitive Science, Institute of Behavioural Sciences,
University of Helsinki, Helsinki, Finland.
** BioMag Laboratory, HUSLAB, Hospital District of Helsinki and Uusimaa, Helsinki, Finland.
alina.leminen@helsinki.fi
How is morphological and morphosyntactic information processed during sentence reading? Are
the neural mechanisms underlying word- and phrase-level combinatorial processing same or
different? Here, electroencephalography (EEG) and magnetoencephalography (MEG) responses
were recorded simultaneously during silent reading of Finnish sentences. The experimental
conditions included 1) well-formed grammatical sentences (correct condition), 2) sentences
containing morphosyntactic violations (adjective-noun number agreement violations), 3)
morphological violations (incorrect stem allomorph and inflectional suffix combination), and 4)
combined violations, containing both morphosyntactic and morphological violations. Signal
space and source reconstruction (sLORETA) results showed that morphosyntactic violation
elicited a left anterior negativity effect, generated in the left inferior frontal cortices. On the other
hand, incorrect stem allomorph and suffix combination elicited an N400-like negativity, which
was localized to the right temporal cortices. Both the LAN and the N400 effects were elicited in
the 410–430 time range after the critical word onset. Furthermore, phrase- and word-level
violations elicited the P600 effects, which, however had different neural source lateralization in
the morphological and morphosyntactic conditions. Source modeling evidence thus suggests
different hemispheric organization of neural networks involved in morphological and
morphosyntactic analyses. Word-level and phrase-level parsing processes are governed by near
simultaneously activated but parallel and distinct fronto-temporal cortical networks.
Keywords: morphology, morphosyntax, MEG