Friday, December 26, 2014

Several articles on aging brains.

Talking about aging brains is sort of a downer, but it's something I feel like I want to do as I trek onward with open eyes from my current age of 72 years. So, pointers to three recent articles on brain changes in aging:

Douaud et al. characterize a common brain network linking development, aging, and vulnerability to disease. They show that the idea of brain decline mirroring brain development is correct. Analysis of structural brain images reveals that a network of mainly higher-order regions that develop relatively late during adolescence demonstrate accelerated degeneration in old age.

And, from Salami et al.:
Aging is accompanied by disruptive alterations in large-scale brain systems, such as the default mode network (DMN) and the associated hippocampus (HC) subsystem, which support higher cognitive functions. However, the exact form of DMN–HC alterations and concomitant memory deficits is largely unknown. We identified age-related decrements in resting-state functional connectivity of the cortical DMN, whereas elevated connectivity between the bilateral HC was found along with attenuated HC–cortical connectivity. Critically, elevated HC at rest restricts the degree to which HC interacts with other brain regions during memory tasks, and thus results in memory deficits. This study provides empirical evidence of how the relationship between the DMN and HC breaks down in aging and how such alterations underlie deficient mnemonic processing.

Finally, Yotsumoto et al. find white matter in the older brain is more plastic than in the younger brain. Its changes during learning a visual perceptual task are not observed when younger subjects learn the same task.

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