The Origin of Word-related Motor Activity

Citation:

Papeo, L., Lingnau, A., Agosta, S., Pascual-Leone, A., Battelli, L., & Caramazza, A. (2014). The Origin of Word-related Motor Activity. Cerebral Cortex.
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Abstract:

Conceptual processing of verbs consistently recruits the left pos- terior middle temporal gyrus (lpMTG). The left precentral motor cortex also responds to verbs, with higher activity for action than nonaction verbs. The early timing of this effect has suggested that motor features of wordsmeaning are accessed directly, bypassing access to conceptual representations in lpMTG. An alternative hypothesis is that the retrieval of conceptual representations in lpMTG is necessary to drive more specific, motor-related represen- tations in the precentral gyrus. To test these hypotheses, we first showed that repetitive transcranial magnetic stimulation (rTMS) applied to the verb-preferring lpMTG site selectively impoverished the semantic processing of verbs. In a second experiment, rTMS per- turbation of lpMTG, relative to no stimulation (no-rTMS), eliminated the actionnonaction verb distinction in motor activity, as indexed by motor-evoked potentials induced in peripheral muscles with single- pulse TMS over the left primary motor cortex. rTMS pertubation of an occipital control site, relative to no-rTMS, did not affect the actionnonaction verb distinction in motor activity, but the verb con- trast did not differ reliably from the lpMTG effect. The results show that lpMTG carries core semantic information necessary to drive the activation of specific (motor) features in the precentral gyrus. 

Last updated on 04/01/2016