Tag: Action Semantics

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

Parkinson’s disease compromises the appraisal of action meanings evoked by naturalistic texts

Parkinson’s disease compromises the appraisal of action meanings evoked by naturalistic texts

Published in: Cortex, Volume 100, March 2018, 111-126

Abstract
“The linguistic profile of Parkinson’s disease (PD) is characterized by difficulties in processing units which denote bodily movements. However, the available evidence has low ecological validity, as it stems from atomistic tasks which are never encountered in real life. Here, we assessed whether such deficits also occur for meanings evoked by context-rich narratives, considering patients with and without mild cognitive impairment (PD-MCI and PD-nMCI, respectively) and matched controls for each group. Participants read two naturalistic stories (an action text and a neutral text) and responded to questions tapping the appraisal of verb-related and circumstantial information. In PD-MCI, impairments in the appraisal of action meanings emerged alongside difficulties in other categories, but they were unique in their independence from general cognitive dysfunction. However, in PD-nMCI, deficits were observed only for action meanings, irrespective of the patients’ domain-general skills (executive functions and general cognitive state). Also, using multiple group discriminant functionanalyses, we found that appraisal of action meanings was the only discourse-level variable that robustly contributed to classifying PD-MCI patients from controls (with an accuracy of 88% for all participants and for each sample separately). Moreover, this variable actually superseded a sensitive executive battery in discriminating between PD-nMCI and controls (with a combined accuracy of 83% for all participants, correctly classifying 79.2% of patients and 87.5% of controls). In sum, action appraisal deficits seem to constitute both a hallmark of naturalistic discourse processing in PD and a sensitive subject-level marker for patients with and without MCI. Such findings highlight the relevance of ecological measures of embodied cognitive functions in the assessment of this population.”

Written by: Adolfo M. Garcia, Yamile Bocanegra, Elena Herrera, Leonardo Moreno, Jairo Carmona, Ana Baena, Francisco Lopera, David Pineda, Margherita Melloni, Agustina Legaz, Edinson Muñoz, Lucas Sedeño, Sandra Baez, Agustin Ibañez
For full text: https://doi.org/10.1016/j.cortex.2017.07.003

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