#CAN13 Can a second language slow down brain aging?

This is part of a blog post series for the 2013 Canadian Association for Neuroscience annual conference. 

Poster: Lifelong Bilingualism Is Associated With Larger Grey And White Matter Volumes In The Temporal Lobe. RK Olsen et al. Rotman Reserach Institute Baycrest.

Here’s another reason to learn a second language: bilingualism staves off “senile moments” well into your 70s.

With aging, our cognition inevitably declines – some faster than others. One brake that slows this process is the ability to fluently speak two or more languages. Researchers have long known that bilinguals’ brains are more resilient to age-related damage than monolinguals. In elderly bilinguals, even when cellular signs of aging are present, their minds stay sharp.

Why do bilinguals have this “cognitive reserve” to buffer aging? Researchers recruited 14 lifelong monolinguals and bilinguals to participate in a brain-imaging study. To qualify, the bilinguals had to have mastered both languages before 11 years old, and remained proficient at the time of testing. Researchers used two imaging techniques (MRI and Diffusion Tensor Imaging, for those interested) to look at brain volume and wiring between the two hemispheres.

Compared to monolinguals, bilinguals had greater brain volume in both frontal and temporal lobes, areas important for reasoning and language, respectively (and much, much more, of course!). On closer inspection, the amount of neuronal bodies (“grey matter”) wasn’t different between the two groups. What was different was the amount of “white matter”, or number of neuronal projections and glial cells, in both lobes. This was associated with greater white matter integrity in the left frontal lobe, and those between the two brain hemispheres.

Researchers think that greater white matter volume and integrity in bilinguals may explain their resistance to brain aging and cognitive decline. At the moment this is purely correlational. It’s possible that bilinguals also like to be cognitive challenged in other ways, leading to similar changes. But I’ll take it. Many questions remain. Can a second language learned later in life have the same effect? What about sign language? What other changes are going on in the brain with language learning and use? Can learning a second language in youth stop or slow neurodegeneration later in life?


PS. In other neuro-news:

High visceral fat is associated with low cognitive (executive) function in female but not male adolescents. Total body fat didn’t seem to matter. The study included 983 kids aged 12-18. (Visceral Fat Is Associated With Lower Executive Functioning In Adolescents. Deborah H Schwartz, Rotman Research Institute, Toronto)

A high fat diet lowers long-term potentiation, a process associated with learning and memory, in female rats. But we don’t know why. (Diet-Induced Obesity Disrupts Hippocampal Synaptic Plasticity and May Alter NMDA Receptor Subunit Expression in Female Animals. Dimitri Pavlov. University of Waterloo)

A dietary supplement, CDP-choline, seems to improve attention in people who can’t pay attention. This was measured by both brain waves (P300, EEG) and performance. All it took was 1 dose of 500mg. CDP-choline seems to be acting through the alpha7 nicotinic receptor. On the other hand, the same dose impaired performance of naturally attentive people. Cognitive enhancer? Probably not. (The Use of CDP-Choline to Modulate Cognitive Processes and Brain State Arousal Implicated in Schizophrenia: A Pilot Study in Healthy Volunteers. Sara I De La Salle. Institute of Mental Health Research, University of Ottawa)