Processing Abstract Language Modulates Motor System Activity

TLDR

Embodiment theory proposes that perception and action systems are engaged during language comprehension, yet prior neuroimaging has only shown modulation for concrete language, and the present study relates these findings to the mirror neuron system. The study provides neurophysiological evidence that motor system activity is modulated during comprehension of both concrete and abstract language. Using an action‑sentence compatibility paradigm and single‑pulse transcranial magnetic stimulation, the authors examined corticospinal excitability while participants read sentences describing object or information transfer. They observed faster responses when sentence direction matched hand movement and greater corticospinal modulation for sentences describing transfer of both concrete objects and abstract information compared to non‑transfer sentences.

Abstract

Embodiment theory proposes that neural systems for perception and action are also engaged during language comprehension. Previous neuroimaging and neurophysiological studies have only been able to demonstrate modulation of action systems during comprehension of concrete language. We provide neurophysiological evidence for modulation of motor system activity during the comprehension of both concrete and abstract language. In Experiment 1, when the described direction of object transfer or information transfer (e.g., away from the reader to another) matched the literal direction of a hand movement used to make a response, speed of responding was faster than when the two directions mismatched (an action-sentence compatibility effect). In Experiment 2, we used single-pulse transcranial magnetic stimulation to study changes in the corticospinal motor pathways to hand muscles while reading the same sentences. Relative to sentences that do not describe transfer, there is greater modulation of activity in the hand muscles when reading sentences describing transfer of both concrete objects and abstract information. These findings are discussed in relation to the human mirror neuron system.