Listening to Action-related Sentences Activates Fronto-parietal Motor Circuits

TLDR

Observing others’ actions activates the cortical circuits that plan and execute those actions, and this mirror‑neuron system is believed to be crucial for understanding observed actions. The study aimed to determine whether this system also activates during the processing of action‑related sentences. Using fMRI, participants listened to sentences describing mouth, hand, or leg actions while abstract control sentences of similar syntax were presented. Listening to action‑related sentences engaged a left fronto‑parieto‑temporal network—including Broca’s area, motor‑coded premotor sectors, the inferior parietal lobule, intraparietal sulcus, and posterior middle temporal gyrus—providing the first direct evidence that such sentences recruit visuomotor circuits involved in action execution and observation.

Abstract

Observing actions made by others activates the cortical circuits responsible for the planning and execution of those same actions. This observation-execution matching system (mirror-neuron system) is thought to play an important role in the understanding of actions made by others. In an fMRI experiment, we tested whether this system also becomes active during the processing of action-related sentences. Participants listened to sentences describing actions performed with the mouth, the hand, or the leg. Abstract sentences of comparable syntactic structure were used as control stimuli. The results showed that listening to action-related sentences activates a left fronto-parieto-temporal network that includes the pars opercularis of the inferior frontal gyrus (Broca's area), those sectors of the premotor cortex where the actions described are motorically coded, as well as the inferior parietal lobule, the intraparietal sulcus, and the posterior middle temporal gyrus. These data provide the first direct evidence that listening to sentences that describe actions engages the visuomotor circuits which subserve action execution and observation.