I often talk about the importance of attitudes and beliefs for memory and cognition. A new honey bee study provides support for this in relation to the effects of aging on the brain, and suggests that this principle extends across the animal kingdom.
The latest finding from the large, long-running Health, Aging, and Body Composition (Health ABC) Study adds to the evidence that preventing or controlling diabetes helps prevent age-related cognitive decline.
I’ve reported before on the evidence suggesting that carriers of the ‘Alzheimer’s gene’, APOE4, tend to have smaller brain volumes and perform worse on cognitive tests, despite being cognitively ‘normal’. However, the research hasn’t been consistent, and now a new study suggests the reason.
A study involving 75 perimenopausal women aged 40 to 60 has found that those with memory complaints tended to show impairments in working memory and attention. Complaints were not, however, associated with verbal learning or memory.
Complaints were also associated with depression, anxiety, somatic complaints, and sleep disturbance. But they weren’t linked to hormone levels (although estrogen is an important hormone for learning and memory).
Previous research has pointed to a typical decline in our sense of control as we get older. Maintaining a sense of control, however, appears to be a key factor in successful aging. Unsurprisingly, in view of the evidence that self-belief and metacognitive understanding are important for cognitive performance, a stronger sense of control is associated with better cognitive performance. (By metacognitive understanding I mean the knowledge that cognitive performance is malleable, not fixed, and strategies and training are effective in improving cognition.)
Another study adds to the evidence that changes in the brain that may lead eventually to Alzheimer’s begin many years before Alzheimer’s is diagnosed. The findings also add to the evidence that what we regard as “normal” age-related cognitive decline is really one end of a continuum of which the other end is dementia.
In the study, 64 older adults (60-74; average 70) and 64 college students were compared on a word recognition task. Both groups first took a vocabulary test, on which they performed similarly. They were then presented with 12 lists of 15 semantically related words. For example, one list could have words associated with "sleep," such as "bed," "rest," "awake," "tired" and "night" — but not the word “sleep”. They were not told they would be tested on their memory of these, rather they were asked to rate each word for pleasantness.
The age at which cognitive decline begins has been the subject of much debate. The Seattle longitudinal study has provided most of the evidence that it doesn’t begin until age 60. A more recent, much larger study that allows both longitudinal and cross-sectional analysis suggests that, depressingly, mid-to-late forties might be closer to the mark.
A certain level of mental decline in the senior years is regarded as normal, but some fortunate few don’t suffer from any decline at all. The Northwestern University Super Aging Project has found seniors aged 80+ who match or better the average episodic memory performance of people in their fifties. Comparison of the brains of 12 super-agers, 10 cognitively-normal seniors of similar age, and 14 middle-aged adults (average age 58) now reveals that the brains of super-agers also look like those of the middle-aged.
The brain changes as we age, but it's not all bad! Experience changes our brains in a good way.
A study involving 36 air traffic controllers and 36 age- and education-matched non-controllers, with 18 older (average age 57) and 18 younger adults (average age 24) per group has found that although predictable age-related declines were observed in most of the standard tests of cognitive function, in the simulated air traffic control task, experience helped the older controllers to compensate to a significant degree for age-related declines, especially in their performance of the more complex simulations.
Nunes, A., & Kramer, A. F. (2009). Experience-based mitigation of age-related performance declines: evidence from air traffic control. Journal of Experimental Psychology. Applied, 15(1), 12-24. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19309213
http://www.eurekalert.org/pub_releases/2009-03/apa-eat031209.php
http://www.eurekalert.org/pub_releases/2009-03/uoia-oat030309.php
A study involving 72 young adults (20-30 years old) and 72 older adults (60-75) has found that regulating emotions – such as reducing negative emotions or inhibiting unwanted thoughts – is a resource-demanding process that disrupts the ability of young adults to simultaneously or subsequently perform tasks, but doesn’t affect older adults. In the study, most of the participants watched a two-minute video designed to induce disgust, while the rest watched a neutral two-minute clip. Participants then played a computer memory game. Before playing 2 further memory games, those who had watched the disgusting video were instructed either to change their negative reaction into positive feelings as quickly as possible or to maintain the intensity of their negative reaction, or given no instructions. Those young adults who had been told to turn their disgust into positive feelings, performed significantly worse on the subsequent memory tasks, but older adults were not affected. The feelings of disgust in themselves did not affect performance in either group. It’s speculated that older adults’ greater experience allows them to regulate their emotions without cognitive effort.
Scheibe, S., & Blanchard-Fields, F. (2009). Effects of regulating emotions on cognitive performance: what is costly for young adults is not so costly for older adults. Psychology and Aging, 24(1), 217-223. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19290754
http://www.eurekalert.org/pub_releases/2009-03/giot-oac030409.php
Another study has found that older adults (average age 70) remember fewer negative images than younger adults (average age 24), and that this has to do with differences in brain activity. When shown negative images, the older participants had reduced interactions between the amygdala and the hippocampus, and increased interactions between the amygdala and the dorsolateral frontal cortex. It seems that the older participants were using thinking rather than feeling processes to store these emotional memories, sacrificing information for emotional stability. The findings are consistent with earlier research showing that healthy seniors are able to regulate emotion better than younger people.
St Jacques, P. L., Dolcos, F., & Cabeza, R. (2009). Effects of aging on functional connectivity of the amygdala for subsequent memory of negative pictures: a network analysis of functional magnetic resonance imaging data. Psychological Science: A Journal of the American Psychological Society APS, 20(1), 74-84. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/19152542
http://www.eurekalert.org/pub_releases/2008-12/uoaf-aba121608.php
http://www.eurekalert.org/pub_releases/2008-12/dumc-oay121508.php
While we take for granted that we’ll lose some cognitive ability as we get older, it’s also true that some very old people have brains just as quick as they always were. Now a post-mortem study of the brains of five of these "super aged" has revealed that these brains do indeed differ from normal elderly brains; specifically, by having much fewer tau tangles. Tau tangles are characteristic of Alzheimer's patients, but they are not restricted to them; until now, it’s been assumed that aging brings about the accumulation of these tangles. However, amyloid plaques, also characteristic of Alzheimer’s and found in smaller quantities in aging brains, were found in “normal” quantities, pointing to the tangles as the critical factor.
The findings were presented November 16, at the Society for Neuroscience annual meeting in Washington, D.C.
http://www.eurekalert.org/pub_releases/2008-11/nu-ab111308.php
A study involving 335 adults aged 21 to 83 found that control beliefs were related to memory performance on a word list recall task for middle-aged and older adults, but not for younger adults. This was partly because middle-aged and older adults who perceived greater control over cognitive functioning were more likely to use strategies to help their memory. In other words, the more you believe there are things you can do to remember information, the more likely you are to make an effort to remember.
Lachman, M.E. & Andreoletti, C. 2006. Strategy Use Mediates the Relationship Between Control Beliefs and Memory Performance for Middle-Aged and Older Adults. J Gerontol B Psychol Sci Soc Sci, 61, P88-P94.
http://www.eurekalert.org/pub_releases/2006-03/bu-cim030706.php
We know that many older adults still retain the mental sharpness of younger people, but studies comparing brain activity in older and younger adults suggests they perform differently. A rat study has now found the first solid evidence that still "sharp" older brains do indeed store and encode memories differently than younger brains. Comparison of those older rats who had retained their cognitive abilities with those who had not, also revealed that those with impaired cognition had lost the ability to modify the strength of the communications between synapses (synaptic communication is the means by which memories are encoded and stored). But the competent seniors also differed from the younger rats in the mechanism most used to bring about synaptic change.
Lee, H.-K., Min, S. S., Gallagher, M., & Kirkwood, A. (2005). NMDA receptor-independent long-term depression correlates with successful aging in rats. Nat Neurosci, 8(12), 1657-1659. Retrieved from http://dx.doi.org/10.1038/nn1586
http://www.eurekalert.org/pub_releases/2005-11/jhu-ob110905.php
A study comparing the ability of young and older adults to indicate which direction a set of bars moved across a computer screen has found that although younger participants were faster when the bars were small or low in contrast, when the bars were large and high in contrast, the older people were faster. The results suggest that the ability of one neuron to inhibit another is reduced as we age (inhibition helps us find objects within clutter, but makes it hard to see the clutter itself). The loss of inhibition as we age has previously been seen in connection with cognition and speech studies, and is reflected in our greater inability to tune out distraction as we age. Now we see the same process in vision.
Betts, L. R., Taylor, C. P., Sekuler, A. B., & Bennett, P. J. (2005). Aging Reduces Center-Surround Antagonism in Visual Motion Processing. Neuron, 45(3), 361-366. Retrieved from http://www.cell.com/neuron/abstract/S0896-6273(05)00013-9
http://psychology.plebius.org/article.htm?article=739
http://www.eurekalert.org/pub_releases/2005-02/mu-opg020305.php
A study involving 193 participants and two experiments, each with a younger (17 – 35 years old) and older (57 – 82 years old) group of adults, has investigated how negative stereotypes about aging influences older adults' memory. Participants were exposed to stereotype-related words in the context of another task (scrambled sentence, word judgment) in order to prime positive and negative stereotypes of aging. Results show memory performance in older adults was lower when they were primed with negative stereotypes than when they were primed with positive stereotypes. Age differences in memory between young and older adults were significantly reduced following a positive stereotype prime, with young and older adults performing at almost identical levels in some situations.
Hess, T. M., Hinson, J. T., & Statham, J. A. (2004). Explicit and implicit stereotype activation effects on memory: do age and awareness moderate the impact of priming? Psychology and Aging, 19(3), 495-505. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15382999
http://www.eurekalert.org/pub_releases/2004-09/apa-se090704.php
The Scottish Mental Survey assessed 87,498 eleven-year-olds in 1932, and another 70,805 in 1947. In a fascinating follow-up to this study, over 1000 of these students have been contacted and re-assessed, on the exact same tests. It was found that, first of all, the seniors did rather better than they had at age 11, and that differences in mental ability remained fairly stable with age. Mental ability at 11 was also found to be significantly correlated with survival — those who scored highly were more likely to have survived, with the exception that men with high ability were more likely to die in active service in World War II. People of lower ability had a greater tendency to lung and stomach cancer. More results from this landmark study are expected.
These preliminary findings were presented by Professor Ian Deary from the Department of Psychology, University of Edinburgh at a symposium on aging at the Australian National University.
http://dsc.discovery.com/news/afp/20030929/aging.html
PET scans of the prefrontal cortex reveal that older adults who perform better on a simple memory task display more activity on both sides of the brain, compared to both older adults who do less well, and younger adults. Although this seems counter-intuitive – the older adults who perform less well show activity patterns more similar to that of younger adults, this supports recent theory that the brain may change tactics as it ages, and that older people whose brain is more flexible can compensate for some aspects of memory decline. Whether this flexibility is neurological, or something that can be taught, is still unknown.
Cabeza, R., Anderson, N. D., Locantore, J. K., & McIntosh, A. R. (2002). Aging gracefully: compensatory brain activity in high-performing older adults. NeuroImage, 17(3), 1394-1402. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/12414279
http://www.nytimes.com/2002/11/19/health/aging/19AGIN.html?8vd
Older adults show two kinds of cognitive-processing deficits: under-recruitment, where appropriate areas of the brain are less likely to be utilized without specific instruction, and non-selective recruitment, where non-relevant regions of the brain are more likely to be used. A recent imaging study confirmed that older adults were less likely than younger ones to use the critical frontal regions when performing a memory task, and more likely to use cortical regions that are not as useful. However, when subjects were given specific strategy instructions, the older adults showed increased activity in the frontal regions, and their remembering improved. Even with this support however, older adults still showed a greater tendency to use brain regions that were not useful.
Logan, J. M., Sanders, A. L., Snyder, A. Z., Morris, J. C., & Buckner, R. L. (2002). Under-recruitment and nonselective recruitment: dissociable neural mechanisms associated with aging. Neuron, 33(5), 827-840. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11879658
http://www.eurekalert.org/pub_releases/2002-02/hhmi-tci021302.php
http://www.eurekalert.org/pub_releases/2002-02/wuis-bis021402.php
Evidence from a series of studies using functional positron emission tomography (PET) images suggests that one way older adults may compensate for age-related cognitive decline is by using additional regions of the brain to perform memory and information processing tasks. For example, simple short-term memory tasks involve the same brain regions in both older and younger adults, but older adults also activate a frontal cortex region that young adults use only when performing complex short-term memory tasks. This may explain why performance of older adults on complex memory tasks is usually significantly poorer than that of younger adults - the frontal cortex region that young adults will activate to help with complex short-term memory tasks is already preoccupied in older adults, and is less available to help when the task becomes more complex.
The research was conducted by University of Michigan researchers under the leadership of cognitive neuroscientist Patricia Reuter-Lorenz, and presented at the annual meeting of the American Psychological Association in San Francisco.