Presentation
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Early language exposure affects neural mechanisms of semantic representations
Poster E18 in Poster Session E, Thursday, October 26, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Xiaosha Wang1, Bijun Wang1, Yanchao Bi1,2; 1Beijing Normal University, Beijing, China, 2Chinese Institute for Brain Research, Beijing, China
One signature of the human brain is its ability to derive knowledge from language inputs, in addition to nonlinguistic sensory channels such as vision and touch. How does human language experience modulate the mechanism by which semantic knowledge is stored in the human brain? Recent work using sensory-deprivation models suggests that a specific brain region (the dorsal anterior temporal lobe, dATL) may represent fully non-sensory knowledge, presumably derived from language. The positive evidence for the necessity of language experiences for the neural semantic representation here is still lacking. We investigated this question using a unique human model with varying amounts and qualities of early language exposure: early deaf adults (delayed signers) who were born to hearing parents and had reduced early exposure and delayed acquisition of any natural human language (speech or sign), with early deaf adults (native signers) who acquired sign language from birth as the control group that matches on nonlinguistic sensory experiences. Sixteen native deaf signers and 23 delayed deaf signers were recruited for the study. In the MRI scanner, participants were presented with 90 written words that were highly familiar to both groups and were instructed to think about word meanings and to perform an oddball one-back semantic judgment task. Group differences were examined first in three regions of interests (ROI): the left dATL, the left posterior middle temporal gyrus, and the left inferior frontal gyrus, followed by whole-brain exploratory analyses. We found that the deaf group with reduced early language exposure, compared with the deaf control group, showed reduced semantic sensitivity, in both multivariate pattern (semantic structure encoding) and univariate (abstractness effect) analyses, in the left dorsal anterior temporal lobe (dATL). These results provide positive, causal evidence that language experience drives the neural semantic representation in the dATL, highlighting the roles of language in forming human neural semantic structures beyond nonverbal sensory experiences.
Topic Areas: Meaning: Lexical Semantics, Language Development/Acquisition