Summary: Aging bilingual brains are more efficient and economical with their resources, a new study reports.
Source: University of Montreal.
New research shows that bilingual people are great at saving brain power.
To do a task, the brain recruits different networks, or the highways on which different types of information flow, depending on the task to be done. The team of Ana Inés Ansaldo, PhD, a researcher at the Centre de recherche de l’Institut universitaire de gériatrie de Montréal and a professor at Université de Montréal, compared what are known as functional brain connections between seniors who are monolingual and seniors who are bilingual. Her team established that years of bilingualism change how the brain carries out tasks that require concentrating on one piece of information without becoming distracted by other information. This makes the brain more efficient and economical with its resources.
To arrive at this finding, Dr. Ansaldo’s team asked two groups of seniors (one of monolinguals and one of bilinguals) to perform a task that involved focusing on visual information while ignoring spatial information. The researchers compared the networks between different brain areas as people did the task. They found that monolinguals recruited a larger circuit with multiple connections, whereas bilinguals recruited a smaller circuit that was more appropriate for the required information. These findings were published in the Journal of Neurolinguistics.
Two different ways of doing the same task
The participants did a task that required them to focus on visual information (the colour of an object) while ignoring spatial information (the position of the object). The research team observed that the monolingual brain allocates a number of regions linked to visual and motor function and interference control, which are located in the frontal lobes. This means that the monolingual brain needs to recruit multiple brain regions to do the task.
“After years of daily practice managing interference between two languages, bilinguals become experts at selecting relevant information and ignoring information that can distract from a task. In this case, bilinguals showed higher connectivity between visual processing areas located at the back of the brain. This area is specialized in detecting the visual characteristics of objects and therefore is specialized in the task used in this study. These data indicate that the bilingual brain is more efficient and economical, as it recruits fewer regions and only specialized regions,” explained Dr. Ansaldo.
Bilinguals have a double advantage as they age
Bilinguals therefore have two cognitive benefits. First, having more centralized and specialized functional connections saves resources compared to the multiple and more diverse brain areas allocated by monolinguals to accomplish the same task. Second, bilinguals achieve the same result by not using the brain’s frontal regions, which are vulnerable to aging. This may explain why the brains of bilinguals are better equipped at staving off the signs of cognitive aging or dementia.
“We have observed that bilingualism has a concrete impact on brain function and that this may have a positive impact on cognitive aging. We now need to study how this function translates to daily life, for example, when concentrating on one source of information instead of another, which is something we have to do every day. And we have yet to discover all the benefits of bilingualism,” concluded Dr. Ansaldo.
Ana Inés Ansaldo, PhD, is a researcher at the Research Centre of the Institut universitaire de gériatrie de Montréal (IUGM) and a professor at the School of Speech Therapy and Audiology at Université de Montréal.
Source: Julie Gazaille – University of Montreal
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Full open access research for “Interference control at the response level: Functional networks reveal higher efficiency in the bilingual brain” by Pierre Berroir, Ladan Ghazi-Saidi, Tanya Dash, Daniel Adrover-Roig, Habib Benali, Ana Inés Ansaldo in Journal of Neurolinguistics. Published online October 16 2016 doi:10.1016/j.jneuroling.2016.09.007
Interference control at the response level: Functional networks reveal higher efficiency in the bilingual brain
The bilingual advantage in interference control tasks has been studied with the Simon task, among others. The mixed evidence from the existing studies has led to contradictions in the literature regarding the bilingual advantage. Moreover, fMRI evidence on the neural basis of interference control mechanisms with the Simon task is limited. Previous work by our team showed that equivalent performance on the Simon task was associated with different activation maps in elderly bilinguals and monolinguals. This study aims to provide a more in-depth perspective on the neural bases of performance on the Simon task in elderly bilinguals and monolinguals, by adopting a network perspective for the functional connectivity analysis. A node-by-node analysis led to the identification of the specific topology that characterized the bilingual and monolingual functional networks and the degree of connectivity between each node across groups. Results showed greater connectivity in bilinguals in the inferior temporal sulcus, which plays a role in visuospatial processing. On the other hand, in monolinguals, brain areas involved in visual, motor, executive functions and interference control were more connected to resolve the same task. In other words, in comparison to the monolingual brain, the bilingual brain resolves visuospatial interference economically, by allocating fewer and more clustered regions. These results demonstrate a larger global efficiency in task performance in bilinguals as compared to monolinguals. Also, the provided evidence filters out the task-specific so-called bilingual advantage discussed in the literature and posits that bilinguals are strategically more efficient in a given performance than monolinguals, thus enhancing our understanding of successful aging.
“Interference control at the response level: Functional networks reveal higher efficiency in the bilingual brain” by Pierre Berroir, Ladan Ghazi-Saidi, Tanya Dash, Daniel Adrover-Roig, Habib Benali, Ana Inés Ansaldo in Journal of Neurolinguistics. Published online October 16 2016 doi:10.1016/j.jneuroling.2016.09.007