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. There was no correlation with size or density of the large, mushroom-shaped spines, which were very stable across age and probably mediate long-term memories, enabling the retention of expertise and skills learned early in life. There was no correlation with any of these spine characteristics once the task was learned. The findings underscore the importance of building skills and broad expertise when young.
One cause of cognitive decline with age
Reference
Dumitriu, D., Hao, J., Hara, Y., Kaufmann, J., Janssen, W. G. M., Lou, W., … Morrison, J. H. (2010). Selective Changes in Thin Spine Density and Morphology in Monkey Prefrontal Cortex Correlate with Aging-Related Cognitive Impairment. J. Neurosci., 30(22), 7507-7515. Retrieved from http://www.jneurosci.org/cgi/content/abstract/30/22/7507
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What causes word finding failures in young and older adults
Journal Article
Burke, D.M., MacKay, D.G., Worthley, J.S. & Wade, E. (1991). On the tip of the tongue: What causes word finding failures in young and older adults. Journal of Memory and Language, 30, 542-579.
- Failing to immediately retrieve well-known information does become more common with age.
- An increase in "tips of the tongue" is evident as early as the mid-thirties.
- The increase in memory failures applies to names of people and things; abstract words do not get harder to recall.
- The length of time before the missing word is recalled also increases with age.
- Older people tend to be less likely than younger people to actively pursue a missing word.
It is common for people to feel as they get older that they more frequently experience occasions when they cannot immediately retrieve a word they know perfectly well ("it's on the tip of my tongue").
Tips of the tongue (TOTs) do indeed increase with age, and this increase is evident as early as the mid-thirties. There are other differences however, in the TOT experiences as people age. For example, older adults are much more likely to "go blank" than either young or mid-age (35-45) adults. That is, younger adults are more likely to be able to retrieve some information about the target word.
At all ages, the most common type of word involved in TOTs is proper names. But while forgetting proper names and object names becomes more common as we get older, interestingly, abstract words are forgotten less.
The most common means of resolution at all ages is that the forgotten word simply "pops up", but as we get older, it takes longer before this happens. "Pop-ups" are relatively more common for older adults. It is suggested that this may be because they are less likely to actively attempt to retrieve the information. According to a questionnaire, older adults are more likely to simply relax and think about something else.
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Submitted by Fiona McPherson
on
Data from 6257 older adults (aged 55-90) evaluated from 2005-2012 has revealed that concerns about memory should be taken seriously, with subjective complaints associated with a doubled risk of developing mild cognitive impairment or dementia, and subjective complaints supported by a loved one being associated with a fourfold risk. Complaints by a loved one alone were also associated with a doubled risk. Among those with MCI, subjective complaints supported by a loved one were associated with a threefold risk of converting to dementia.
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Submitted by Fiona McPherson
on
A large Danish study comparing two groups of nonagenarians born 10 years apart has found that not only were people born in 1915 nearly a third (32%) more likely to reach the age of 95 than those in the 1905 cohort, but members of the group born in 1915 performed significantly better on tests of cognitive ability and activities of daily living. Additionally, significantly more members of the later cohort scored maximally on the MMSE (23% vs 13% of the earlier cohort).
Site of plaque buildup matters
Submitted by Fiona McPherson
on
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