Neural correlates of semantic priming for ambiguous words: an event-related fMRI study.
We investigated the neural correlates of semantic priming by using event-related fMRI to record blood oxygen level dependent (BOLD) responses while participants performed speeded lexical decisions (word/nonword) on visually presented related versus unrelated prime-target pairs. A long stimulus onset asynchrony of 1000 ms was employed, which allowed for increased controlled processing and selective frequency-based ambiguity priming. Conditions included an ambiguous word prime (e.g. bank) and a target related to its dominant (e.g. money) or subordinate meaning (e.g. river). Compared to an unrelated condition, primed dominant targets were associated with increased activity in the LIFG, the right anterior cingulate and superior temporal gyrus, suggesting postlexical semantic integrative mechanisms, while increased right supramarginal activity for the unrelated condition was consistent with expectancy based priming. Subordinate targets were not primed and were associated with reduced activity primarily in occipitotemporal regions associated with word recognition, which may be consistent with frequency-based meaning suppression. These findings provide new insights into the neural substrates of semantic priming and the functional-anatomic correlates of lexical ambiguity suppression mechanisms.
Copland
David A
DA
Centre for Research in Language Processing and Linguistics, Division of Speech Pathology, The University of Queensland, St Lucia, QLD, 4072, Australia. d.copland@uq.edu.au
de Zubicaray
Greig I
GI
McMahon
Katie
K
Eastburn
Matt
M
D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D012660:Semantics; D013060:Speech / Q000502:physiology*; D013702:Temporal Lobe / Q000033:anatomy & histology / Q000502:physiology; D014705:Verbal Behavior / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology