Personality may influence brain shrinkage in aging

While brain training programs can certainly improve your ability to do the task you’re practicing, there has been little evidence that this transfers to other tasks. In particular, the holy grail has been very broad transfer, through improvement in working memory. While there has been some evidence of this in pilot programs for children with ADHD, a new study is the first to show such improvement in older adults using a commercial brain training program.

Another study has come out showing that older adults with low levels of vitamin D are more likely to have cognitive problems. The six-year study followed 858 adults who were age 65 or older at the beginning of the study. Those who were severely deficient in vitamin D were 60% more likely to have substantial cognitive decline, and 31% more likely to have specific declines in executive function, although there was no association with attention.

Anticholinergics are widely used for a variety of common medical conditions including insomnia, allergies, or incontinence, and many are sold over the counter. Now a large six-year study of older African-Americans has found that taking one anticholinergic significantly increased an individual's risk of developing mild cognitive impairment and taking two of these drugs doubled this risk. The risk was greater for those who didn’t have the ‘Alzheimer’s gene’, APOE-e4.

A rat study demonstrates how specialized brain training can reverse many aspects of normal age-related cognitive decline in targeted areas. The month-long study involved daily hour-long sessions of intense auditory training targeted at the primary auditory cortex. The rats were rewarded for picking out the oddball note in a rapid sequence of six notes (five of them of the same pitch). The difference between the oddball note and the others became progressively smaller. After the training, aged rats showed substantial reversal of their previously degraded ability to process sound.

A very large study of older women has found that although there was a small downward trend in cognitive function (as measured by the MMSE) with increasing obesity, this trend was almost entirely driven by those with a waist-hip ratio below 0.78 — that is, for women who carry excess weight around their hips, known as pear shapes (as opposed to carrying it around the waist, called apple shapes).

A review of the many recent studies into the effects of music training on the nervous system strongly suggests that the neural connections made during musical training also prime the brain for other aspects of human communication, including learning. It’s suggested that actively engaging with musical sounds not only helps the plasticity of the brain, but also helps provide a stable scaffolding of meaningful patterns. Playing an instrument primes the brain to choose what is relevant in a complex situation.

Although research has so far been confined to mouse studies, researchers are optimistic about the promise of histone deacetylase inhibitors in reversing age-related memory loss — both normal decline, and the far more dramatic loss produced by Alzheimer’s. The latest study reveals that memory impairment in the aging mouse is associated with altered hippocampal chromatin plasticity, specifically with the failure of histone H4 lysine 12 acetylation, leading to a failure to initiate the gene expression program associated with memory consolidation.

A rhesus monkey study has revealed which dendritic spines are lost with age, providing a new target for therapies to help prevent age-association cognitive impairment. It appears that it is the thin, dynamic spines in the dorsolateral prefrontal cortex, which are key to learning new things, establishing rules, and planning, that are lost. Learning of a new task was correlated with both synapse density and average spine size, but was most strongly predicted by the head volume of thin spines.

Studies on the roundworm C. elegans have revealed that the molecules required for learning and memory are the same from C. elegans to mammals, suggesting that the basic mechanisms underlying learning and memory are ancient, and that this animal can serve as a testing ground for treatments for age-related memory loss. Intriguingly, a comparison of two known regulators of longevity — reducing calorie intake and reducing activity in the insulin-signaling pathway (achieved through genetic manipulation) — has found that these two treatments produce very different effects on memory.

A study involving 54 older adults (66-76) and 58 younger adults (18-35) challenges the idea that age itself causes people to become more risk-averse and to make poorer decisions. Analysis revealed that it is individual differences in processing speed and memory that affect decision quality, not age. The stereotype has arisen no doubt because more older people process slowly and have poorer memory.