Cognitive Benefit of Lifelong Bilingualism

Jan. 5, 2013 — Seniors who have spoken two languages since childhood are faster than single-language speakers at switching from one task to another, according to a study published in the January 9 issue of The Journal of Neuroscience. Compared to their monolingual peers, lifelong bilinguals also show different patterns of brain activity when making the switch, the study found.


 

The findings suggest the value of regular stimulating mental activity across the lifetime. As people age, cognitive flexibility — the ability to adapt to unfamiliar or unexpected circumstances — and related “executive” functions decline. Recent studies suggest lifelong bilingualism may reduce this decline — a boost that may stem from the experience of constantly switching between languages. However, how brain activity differs between older bilinguals and monolinguals was previously unclear.

In the current study, Brian T. Gold, PhD, and colleagues at the University of Kentucky College of Medicine, used functional magnetic resonance imaging (fMRI) to compare the brain activity of healthy bilingual seniors (ages 60-68) with that of healthy monolingual seniors as they completed a task that tested their cognitive flexibility. The researchers found that both groups performed the task accurately. However, bilingual seniors were faster at completing the task than their monolingual peers despite expending less energy in the frontal cortex — an area known to be involved in task switching.

“This study provides some of the first evidence of an association between a particular cognitively stimulating activity — in this case, speaking multiple languages on a daily basis — and brain function,” said John L. Woodard, PhD, an aging expert from Wayne State University, who was not involved with the study. “The authors provide clear evidence of a different pattern of neural functioning in bilingual versus monolingual individuals.”

The researchers also measured the brain activity of younger bilingual and monolingual adults while they performed the cognitive flexibility task.

Overall, the young adults were faster than the seniors at performing the task. Being bilingual did not affect task performance or brain activity in the young participants. In contrast, older bilinguals performed the task faster than their monolingual peers and expended less energy in the frontal parts of their brain.

“This suggests that bilingual seniors use their brains more efficiently than monolingual seniors,” Gold said. “Together, these results suggest that lifelong bilingualism may exert its strongest benefits on the functioning of frontal brain regions in aging.”

This research was funded by the U.S. National Institutes of Health and the National Science Foundation.


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The above story is reprinted from materials provided bySociety for Neuroscience (SfN).

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Society for Neuroscience (SfN) (2013, January 5). Cognitive benefit of lifelong bilingualism.ScienceDaily. Retrieved January 12, 2013, from http://www.sciencedaily.com/releases/2013/01/130108201519.htm

Cheating Slime Mold Gets the Upper Hand

Jan. 7, 2013 — A  ‘cheater’ mutation (chtB) in Dictyostelium discoideum, a free living slime mould able to co-operate as social organism when food is scarce, allows the cheater strain to exploit its social partner, finds a new study published in BioMed Central’s open access journal BMC Evolutionary Biology. The mutation ensures that when mixed with ‘normal’ Dictyostelium  more than the fair share of cheaters become spores, dispersing to a new environment, and avoiding dying as stalk cells.

Dictyostelium have an unusual life style. They generally live as individual amoeboid cells, eating bacteria in leaf litter and soil. However when they run out of food they form a multi-cellular ‘slug’ capable of travelling to a new environment. However if conditions are right they behave more like a fungus, producing a stalk and a fruiting body which releases spores. During this co-operative behaviour approximately 20% become stalk cells which are doomed to starvation but, after dispersal, the spores germinate into new amoeba.

The chtB strain is able to reduce the ability of normal Dictyostelium to form spores so that when mixed in equal numbers with wild typeDictyostelium 60% of the spores will be chtB. The chtB mutation appeared to be normal in all other respects and the mutation had no ‘fitness cost’ which might impede its behaviour or lifespan. In fact the mutation allowed chtB to divide faster in liquid medium.

Dr Lorenzo Santorelli from the University of Oxford who led this study, conducted at Baylor College of Medicine in the Shaulsky lab explained, “chtB cells inhibit the pre-spore gene cotB in their wild type partner. This appears to force the wild type Dictyostelium to become cells at the base of the stalk rather than stalk cells or spores. Cheaters are essentially parasites, but we could not find the expected fitness cost which usually prevents such cheaters from taking over.”



(Credit: Lorenzo A Santorelli, Adam Kuspa, Gad Shaulsky, David C Queller and Joan E Strassmann)

 

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The above story is reprinted from materials provided byBioMed Central Limited.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Lorenzo A Santorelli, Adam Kuspa, Gad Shaulsky, David C Queller and Joan E Strassmann. A new social gene in Dictyostelium discoideum, chtBBMC Evolutionary Biology, 2013 (in press) [link]
BioMed Central Limited (2013, January 7). Cheating slime mold gets the upper hand.ScienceDaily. Retrieved January 12, 2013, from http://www.sciencedaily.com/releases/2013/01/130108201515.htm

Sweetened Drinks Linked to Depression, Coffee Tied to Lower Risk

Jan. 8, 2013 — New research suggests that drinking sweetened beverages, especially diet drinks, is associated with an increased risk of depression in adults while drinking coffee was tied to a slightly lower risk. The study was released January 8 and will be presented at the American Academy of Neurology’s 65th Annual Meeting in San Diego, March 16 to 23, 2013.


 

“Sweetened beverages, coffee and tea are commonly consumed worldwide and have important physical — and may have important mental — health consequences,” said study author Honglei Chen, MD, PhD, with the National Institutes of Health in Research Triangle Park in North Carolina and a member of the American Academy of Neurology.

The study involved 263,925 people between the ages of 50 and 71 at enrollment. From 1995 to 1996, consumption of drinks such as soda, tea, fruit punch and coffee was evaluated. About 10 years later, researchers asked the participants whether they had been diagnosed with depression since the year 2000. A total of 11,311 depression diagnoses were made.

People who drank more than four cans or cups per day of soda were 30 percent more likely to develop depression than those who drank no soda. Those who drank four cans of fruit punch per day were about 38 percent more likely to develop depression than those who did not drink sweetened drinks. People who drank four cups of coffee per day were about 10 percent less likely to develop depression than those who drank no coffee. The risk appeared to be greater for people who drank diet than regular soda, diet than regular fruit punches and for diet than regular iced tea.

“Our research suggests that cutting out or down on sweetened diet drinks or replacing them with unsweetened coffee may naturally help lower your depression risk,” said Chen. “More research is needed to confirm these findings, and people with depression should continue to take depression medications prescribed by their doctors.”

The study was supported by the National Institutes of Health, the National Institute of Environmental Health Sciences and the National Cancer Institute.


Story Source:

The above story is reprinted from materials provided byAmerican Academy of Neurology (AAN).

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


American Academy of Neurology (AAN) (2013, January 8). Hold the diet soda? Sweetened drinks linked to depression, coffee tied to lower risk. ScienceDaily. Retrieved January 12, 2013, from http://www.sciencedaily.com/releases/2013/01/130108162135.htm