Tag: Motor Cortex

Representation of action semantics in the motor cortex and Broca’s area

Representation of action semantics in the motor cortex and Broca’s area

Published in: Brain and Language, Volume 179, April 2018, 33-41

Abstract
“Previous studies have shown that both reading action words and observing actions engage the motor cortex and Broca’s area, but it is still controversial whether a somatotopic representation exists for action verbs within the motor cortex and whether Broca’s area encodes action-specific semantics for verbs. Here we examined these two issues using a set of functional MRI experiments, including word reading, action observation and a movement localiser task. Results from multi-voxel pattern analysis (MVPA) showed a somatotopic organisation within the motor areas and action-specific activation in Broca’s area for observed actions, suggesting the representation of action semantics for observed actions in these neural regions. For action verbs, however, a lack of finding for the somatotopic activation argues against semantic somatotopy within the motor cortex. Furthermore, activation patterns in Broca’s area were not separable between action verbs and unrelated verbs, suggesting that Broca’s area does not encode action-specific semantics for verbs.”

Written by: Zuo Zhang, Yaoru Sun, Zijian Wang
For full text: https://doi.org/10.1016/j.bandl.2018.02.003

Embodied cognition: Is activation of the motor cortex essential for understanding action verbs?

Embodied cognition: Is activation of the motor cortex essential for understanding action verbs?

Published in: Journal of Experimental Psychology: Learning, Memory, and Cognition, Volume 44, Issue 3, 335-370

Abstract
“In 8 experiments using language processing tasks ranging from lexical decision to sensibility judgment, participants made hand or foot responses after reading hand- or foot-associated words such as action verbs. In general, response time (RT) tended to be faster when the hand- versus foot-associated word was compatible with the limb that was required to respond (e.g., hand response to a hand-associated word) than when it was incompatible (e.g., foot response to a hand-associated word). To see whether this compatibility effect reflects differential hand- versus foot-specific motor activation produced by the words, as suggested by some embodied theories of language understanding, we monitored 2 event-related potential (ERP) measures previously found to be sensitive to the activation of these limbs. As expected, the ERP results replicated previous findings that the monitored ERPs differ for hand versus foot movements. More importantly, the ERPs provided no evidence of any difference for hand- versus foot-associated words. Thus, the results weaken previous claims that the understanding of action verbs requires activation of the motor areas used to carry out the named action. Instead, they support claims that language-related compatibility effects on RT may arise prior to motor processes, which implies that such effects are not decisive evidence for embodied language understanding.”

Written by: Jeff Miller, Kate Brookie, Sid Wales, Simon Wallace, Barbara Kaup
For full text: http://dx.doi.org/10.1037/xlm0000451

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