The bilingual brain is more efficient at the response level when dealing with interference

The bilingual advantage in tasks of interference control at the visual space level has been studied with the Simon task, among others. Based on the results of several existing studies, the literature on bilingual advantage has given rise to several contradictions. A work and a previous investigation carried out by our team showed an equivalent behavioral performance in the Simon task in the bilingual and monolingual population of advanced age. However, the results established different activation maps and different neural substrates in the bilingual and monolingual population. Thus, it was verified how the right middle frontal rotation was activated in the monolingual population and, therefore, how the frontal-executive areas were used. In the case of the bilingual population, the lower left parietal lobe was activated and, therefore, visual space processing was preferably used.

In this way, this study aims to provide a more detailed perspective on the neural bases during a Simon task in the bilingual and monolingual elderly population, adopting a network perspective to perform a functional connectivity analysis. Therefore, a node by node analysis was carried out, which lead to the identification of the specific typology that characterizes the functional networks of bilinguals and monolinguals, and the degree of connectivity between each node.

The results showed a greater connectivity in bilinguals around lower temporal regions, a structure that makes an important role in visual space processing. On the other hand, it was seen that, in the monolingual, the areas of the brain involved in visual and motor aspects, in the executive functions and in the control of interferences are very connected during the task. These areas forming a large multifunctional network that encompassed several processes and nodes with the objective of addressing executive processing. Thus, we could see how, in comparison with the monolingual brain, the bilingual brain resolves visual space interference by allocating few cerebral resources, economically, with the implication of more restricted and integrated visual spatial processing regions. For this reason, a greater overall efficiency in the performance of certain tasks in bilinguals compared to monolinguals is demonstrated. Finally, and through the discussion of the literature that discusses the bilingual advantage, it was possible to reach the conclusion that the bilinguals were strategically more efficient in certain tasks than the monolingual ones.

Reference: Ansaldo AI, Ghazi Saidi L, Adrover-Roig D. (2015). Interference control in elderly bilinguals: appearances can be misleading. Journal of Clinical and Experimental Neuropsychology;37(5):455-70