How words get meaning: The neural processing of novel object names after sensorimotor training

The hypothesis that individual experience affects the formation and processing of conceptual representations is controversially debated. Previous training studies with novel tool-like objects have found experience effects on conceptual representations as measured in tasks requiring the processing of object pictures. This study instead explored the neural processing of training-induced word meaning of novel object names. We asked whether the type of experience gained during object concept formation specifically modulates object name processing. In three training sessions with novel tool-like objects, two groups of healthy participants gained either active or observational manipulation experience as well as purely visual experience, while learning pseudowords serving as object names. In an fMRI session after training, participants were presented with the learned novel object names in a lexical decision task. Results revealed that processing novel object names in comparison to meaningless pseudowords elicits a word-like activation pattern in frontal, parietal and temporal regions known to underlie lexical-semantic processing, thus suggesting word meaning formation. Experience-specific modulations did not emerge as regional activation effects. However, a post-hoc analysis revealed that the type of experience (manipulation versus visual)as well as the way, in which the manipulation was learned (active versus observational)led to specific functional connectivity increases between semantic regions and neuronal assemblies in brain areas coding for object manipulation and related visuospatial information. These results suggest that the emergence of conceptual processing for novel object names might be grounded in functional brain networks specifically coding for the experience with their referents.