Poster Session C, Sunday, March 24, 5:00 – 7:00 pm, Pacific Concourse
Lesion-symptom mapping analysis of interdependence of motor and language systems
Analia Arevalo1, Guilherme Lepski1,2, Timothy Herron3, Nina Dronkers3,4, Juliana Baldo3; 1University of Sao Paulo School of Medicine, Brazil, 2University of Tuebingen, Germany, 3VA Northern California Health Care System, 4University of California, Berkeley
According to “embodiment theory”, the cortical sensorimotor regions responsible for action execution also underlie action observation, planning, and mental imagery as well as the processing of action-related words. Strict interpretations of these theories contend that the same regions are recruited when 1) executing actions, 2) observing actions, and 3) processing action-related words. However, previous studies have been criticized for not testing all these dimensions using the same stimuli, which would make results more compelling. In the current study, we analyzed behavioral data from 49 single, left hemisphere stroke patients on the Porch Index of Communicative Ability (PICA), which tests object and action comprehension through auditory, verbal, pantomime, gesture and writing modalities with the same stimuli. We used univariate and multivariate lesion-symptom mapping (LSM) to identify brain regions associated with performance across these different modalities. Fusiform gyrus, middle/inferior temporal and middle/inferior occipital cortices were associated with all task categories, while angular gyrus and superior parietal cortex were specifically associated with predominantly motor tasks (copying, pantomime and gesturing) or involving single-word processing (production or comprehension). Finally, word tasks also involved superior temporal cortex. These data corroborate previous findings from our group suggesting that processing action-associated information recruits a broad network of left hemisphere regions not limited to premotor cortex, and contradict the notion that all three dimensions of an embodied network recruit the same set of cortical regions. A clearer map of the key regions involved in sensorimotor processing across task modalities should better inform future clinical interventions.
Topic Area: PERCEPTION & ACTION: Multisensory