Early lexico-semantic modulation of motor related areas during action and non-action verb processing

• Single verb processing evokes a peak in activity at 165 ms post-stimulus onset.
• Bilateral sensorimotor cortex is activated by hand action verbs from 155 to 174 ms.
• Sensorimotor activation is automatic and necessary for action verb understanding.
• Bilateral dorsolateral prefrontal cortex contributes to hand action verb processing.
• Embodied theories of cognition are confirmed.

Although action verb processing deficits have been described in diseases affecting the motor system, research on temporal processing in this area has not been reported. In this study, action and non-action verb processing was contrasted in healthy volunteers using electro-encephalography. These data may serve as a control condition for further research in motor disorders. Latency and amplitude evaluations as well as source reconstruction were applied on event-related potentials. Action verbs evoked higher activation in bilateral sensorimotor areas from 155 to 174 ms and in bilateral dorsolateral prefrontal cortex (DLPFC) from 219 to 238 ms. Hand action verb processing activates the motor programmes of the actions the verbs refer to. This seems not restricted to the core (pre)motor cortical areas of the brain. A broad motor brain network is hypothesized to be involved. While sensorimotor activation seems essential for action verb understanding, this cannot be concluded for DLPFC activation.