Poster D35, Friday, August 17, 4:45 – 6:30 pm, Room 2000AB
Multi-voxel pattern analysis reveals conceptual flexibility and invariance in language
Markus Ostarek1, Jeroen van Paridon1, Peter Hagoort1,2, Falk Huettig1,2;1Max Planck Institute for Psycholinguistics, Nijmegen, 2Donders Institute for Brain, Cognition, and Behavior, Radboud University, Nijmegen
Conceptual processing is characterized by a striking degree of flexibility on the one hand (Barsalou, 1993), and a remarkable capacity for abstraction on the other (Fodor, 1975). Previous behavioral and electrophysiological work established that during language comprehension contextual demands strongly influence the informational content that is activated and the processing systems that are recruited. Recent functional magnetic resonance imaging (fMRI) studies have begun to explore the neuro-cognitive mechanisms underlying conceptual flexibility in language processing. They showed that task relevance of motor or visual features of words leads to higher activation in brain regions involved in movement planning and visual perception (Hoenig, Sim, Bochev, Herrnberger, & Kiefer, 2008; van Dam, van Dijk, Bekkering, & Rueschemeyer, 2012), and to increased functional connectivity between auditory cortex and these areas (Van Dam, Van Dongen, Bekkering, & Rueschemeyer, 2012). Using multi-voxel pattern analysis in fMRI, we investigated how task demands (performing an animacy vs. size judgement task) shape word-specific patterns elicited by nouns, focusing particularly on size and animacy information. Representational similarity analysis revealed that in the left anterior temporal lobe and in primary sensory and association areas size and animacy information was more strongly present when it was task-relevant. Surprisingly, we found no evidence for task invariant processing of size or animacy anywhere in the brain. To further probe flexibility vs. invariance, split half analyses compared how similar word-specific patterns were within and across tasks. The results suggest that patterns in occipital areas are strongly affected by task demands. In contrast, we obtained evidence for task invariant processing in the intraparietal sulcus and surrounding cortex (including the angular gyrus). This region was neither found to be sensitive to animacy or size information, nor to phonological information, suggestive of patterns with a non-systematic mapping to semantic and phonological word features. These results point to a possible neural architecture for conceptual flexibility and invariance in language: Whereas a distributed network encompassing the anterior temporal lobe and sensory areas seems to flexibly adapt to task demands to provide contextually relevant information, the intraparietal sulcus and surrounding cortex may contribute to stable context-invariant processing of words.
Topic Area: Meaning: Lexical Semantics