Resumo

MARINO DAVOLOS, Julián et al. Brain activity measure with functional Magnetic Resonance Imagin during Action Verbal Fluency Task. Neuropsicologia Latinoamericana [online]. 2012, vol.4, n.4, pp. 28-35. ISSN 2075-9479.  http://dx.doi.org/10.5579/rnl.2012.0130.

Action fluency (AF) is a verbal fluency task (VFT) that demands to evoke verbs in a brief time. Several neurological disorders related to the fronto-striatal loop, such as Parkinson's disease dementia, Cerebellar Friedrich Ataxia, Hydrocephalus and HIV dementia, have been demonstrated deficit in AF. In this study, we investigated brain activation during AF performance using functional Magnetic Resonance Imaging (fMRI). We employed a block design type with 'overt' emission of verbs compared to contrast condition of easy number subtractions (with low requirement in working memory). We analyzed the change in the blood oxygenation level-dependent (BOLD) signal in the whole brain and in four specific volumes of interest. We found activation in the left inferior prefrontal gyrus, coinciding with the expected activation of controlled recovery mechanisms. Also, we found significant subcortical activation consistent with data from clinical samples. Consistent with recent reports, no significant activation was found in the regions associated with semantic executive control network: the temporal pole and the posterior temporo- parietal cortex (angular gyrus). This results confirm a frontal activation for verbs compared to nouns, in agreement with reports about the frontal storaging location of verbs in the brain, placed in anterior parts in relation to nouns. This is the first study to evaluate brain activation during the evocation of verbs under a VFT constraints.

Palavras-chave : Action fluency; Verbal fluency tasks; Functional Magnetic Resonance Imaging; Left inferior prefrontal gyrus.

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