Neural correlates of implicit and explicit combinatorial semantic processing. Neuroimage 2010 Nov 01;53(2):638-46
Date
07/06/2010Pubmed ID
20600969Pubmed Central ID
PMC2930088DOI
10.1016/j.neuroimage.2010.06.055Scopus ID
2-s2.0-77956063587 (requires institutional sign-in at Scopus site) 100 CitationsAbstract
Language consists of sequences of words, but comprehending phrases involves more than concatenating meanings: A boat house is a shelter for boats, whereas a summer house is a house used during summer, and a ghost house is typically uninhabited. Little is known about the brain bases of combinatorial semantic processes. We performed two fMRI experiments using familiar, highly meaningful phrases (lake house) and unfamiliar phrases with minimal meaning created by reversing the word order of the familiar items (house lake). The first experiment used a 1-back matching task to assess implicit semantic processing, and the second used a classification task to engage explicit semantic processing. These conditions required processing of the same words, but with more effective combinatorial processing in the meaningful condition. The contrast of meaningful versus reversed phrases revealed activation primarily during the classification task, to a greater extent in the right hemisphere, including right angular gyrus, dorsomedial prefrontal cortex, and bilateral posterior cingulate/precuneus, areas previously implicated in semantic processing. Positive correlations of fMRI signal with lexical (word-level) frequency occurred exclusively with the 1-back task and to a greater spatial extent on the left, including left posterior middle temporal gyrus and bilateral parahippocampus. These results reveal strong effects of task demands on engagement of lexical versus combinatorial processing and suggest a hemispheric dissociation between these levels of semantic representation.
Author List
Graves WW, Binder JR, Desai RH, Conant LL, Seidenberg MSAuthor
Jeffrey R. Binder MD Professor in the Neurology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
BrainBrain Mapping
Databases, Factual
Female
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Male
Mental Processes
Psycholinguistics
Psychomotor Performance
Reaction Time
Reading
Semantics
Young Adult
