Proceedings of the Annual Meeting of the Cognitive Science Society

Do neural systems for planning motor actions play a func-tional role in understanding action language? Across multi-ple neuroimaging studies, processing action verbs correlateswith somatotopic activity in premotor cortex (PMC). Yet, onlyone neurostimulation study supports a functional role for PMCin action verb understanding: paradoxically, inhibiting PMCmade people respond faster to action verbs. Here we investi-gated effects of PMC excitation and inhibition on action verbunderstanding using tDCS. Right-handers received excitatoryor inhibitory stimulation to left PMC hand areas, then madelexical decisions on unimanual action verbs and abstract verbs.tDCS polarity selectively affected how accurately participantsresponded to unimanual action verbs. Inhibitory stimulationto left PMC caused a relative improvement in performance forright-hand responses, whereas excitatory left PMC stimulationcaused a relative impairment. tDCS polarity did not differ-entially affect responses to abstract verbs. Premotor areas thatsubserve planning actions also support understanding languageabout these actions.