A study involving 218 participants aged 18-88 has looked at the effects of age on the brain activity of participants viewing an edited version of a 1961 Hitchcock TV episode (given that participants viewed the movie while in a MRI machine, the 25 minute episode was condensed to 8 minutes).

While many studies have looked at how age changes brain function, the stimuli used have typically been quite simple. This thriller-type story provides more complex and naturalistic stimuli.

Younger adults' brains responded to the TV program in a very uniform way, while older adults showed much more idiosyncratic responses. The TV program (“Bang! You're dead”) has previously been shown to induce widespread synchronization of brain responses (such movies are, after all, designed to focus attention on specific people and objects; following along with the director is, in a manner of speaking, how we follow the plot). The synchronization seen here among younger adults may reflect the optimal response, attention focused on the most relevant stimulus. (There is much less synchronization when the stimuli are more everyday.)

The increasing asynchronization with age seen here has previously been linked to poorer comprehension and memory. In this study, there was a correlation between synchronization and measures of attentional control, such as fluid intelligence and reaction time variability. There was no correlation between synchronization and crystallized intelligence.

The greatest differences were seen in the brain regions controlling attention (the superior frontal lobe and the intraparietal sulcus) and language processing (the bilateral middle temporal gyrus and left inferior frontal gyrus).

The researchers accordingly suggested that the reason for the variability in brain patterns seen in older adults lies in their poorer attentional control — specifically, their top-down control (ability to focus) rather than bottom-up attentional capture. Attentional capture has previously been shown to be well preserved in old age.

Of course, it's not necessarily bad that a watcher doesn't rigidly follow the director's manipulation! The older adults may be showing more informed and cunning observation than the younger adults. However, previous studies have found that older adults watching a movie tend to vary more in where they draw an event boundary; those showing most variability in this regard were the least able to remember the sequence of events.

The current findings therefore support the idea that older adults may have increasing difficulty in understanding events — somthing which helps explain why some old people have increasing trouble following complex plots.

The findings also add to growing evidence that age affects functional connectivity (how well the brain works together).

It should be noted, however, that it is possible that there could also be cohort effects going on — that is, effects of education and life experience.

http://www.eurekalert.org/pub_releases/2015-08/uoc-ymt081415.php

A large, five-year study challenges the idea that omega-3 fatty acids can slow age-related cognitive decline. The study, involving 4,000 older adults, was part of the Age-Related Eye Disease Study (AREDS), which established that daily high doses of certain antioxidants and minerals can help slow the progression of age-related macular degeneration. However, a follow-up study found the addition of omega-3 fatty acids to the AREDS formula made no difference.

Omega-3 fatty acids are believed to be responsible for the health benefits associated with regularly eating fish, which is associated with lower rates of AMD, cardiovascular disease, and possibly dementia.

In this study, participants from the AREDS study, all of whom had early or intermediate AMD, were randomly assigned to either omega-3, or lutein and zeaxanthin (nutrients found in large amounts in green leafy vegetables), or both, or a placebo. As they all had AMD, participants also took the AREDS formula, which includes vitamins C, E, beta carotene, and zinc. Cognitive testing took place at the beginning, at 2 years, and at 4 years.

There was no benefit to these supplements: all groups showed a similar rate of cognitive decline over the study period.

The researchers speculate that the failure to find a benefit may lie in the age of the participants — it may be that supplements, to be of benefit, need to be started earlier. The other possibility (and the one I myself give greater weight to, although both factors may well be influential) is that these nutrients need to be taken in food to be effective.

It should be noted that the omega-3 fatty acids taken were those found in fish, not those found in plant foods such as flaxseed, walnuts, soy products, and canola and soybean oils.

http://www.eurekalert.org/pub_releases/2015-08/nei-nss082115.php

http://www.eurekalert.org/pub_releases/2015-08/tjnj-eop082115.php

More evidence for the benefits of the Mediterranean diet for fighting age-related cognitive decline comes from a large 5-year study. The study involved 960 older adults, whose cognitive change was assessed over 4.7 years. Those who followed the MIND diet more rigorously showed an equivalent of being 7.5 years younger cognitively than those who followed the diet least.

The Mediterranean-DASH Diet Intervention for Neurodegenerative Delay is a hybrid of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets. It requires at least:

• three servings of whole grains every day
• a green leafy vegetable and one other vegetable every day
• a glass of wine
• snack most days on nuts
• beans every other day or so
• poultry at least twice a week
• fish at least once a week
• berries at least twice a week (blueberries are particularly recommended)
• very limited intake of designated unhealthy foods, especially:
  • butter
  • sweets and pastries
  • whole fat cheese
  • fried or fast food

http://www.eurekalert.org/pub_releases/2015-08/rumc-eaa080415.php

http://www.theguardian.com/society/2015/aug/05/diet-high-in-leafy-green-vegetables-may-slow-cognitive-decline-in-elderly-study

I've reported before on the idea that the drop in working memory capacity commonly seen in old age is related to the equally typical increase in distractability. Studies of brain activity have also indicated that lower WMC is correlated with greater storage of distractor information. So those with higher WMC, it's thought, are better at filtering out distraction and focusing only on the pertinent information. Older adults may show a reduced WMC, therefore, because their ability to ignore distraction and irrelevancies has declined.

Why does that happen?

A new, large-scale study using a smartphone game suggests that the root cause is a change in the way we hold items in working memory.

The study involved 29,631 people aged 18—69, who played a smartphone game in which they had to remember the positions of an increasing number of red circles. Yellow circles, which had to be ignored, could also appear — either at the same time as the red circles, or after them. Data from this game revealed both WMC (how many red circle locations the individual could remember), and distractability (how many red circle locations they could remember in the face of irrelevant yellow circles).

Now this game isn't simply a way of measuring WMC. It enables us to make an interesting distinction based on the timing of the distraction. If the yellow circles appeared at the same time as the red ones, they are providing distraction when you are trying to encode the information. If they appear afterward, the distraction occurs when you are trying to maintain the information in working memory.

Now it would seem commonsensical that distraction at the time of encoding must be the main problem, but the fascinating finding of this study is that it was distraction during the delay (while the information is being maintained in working memory) that was the greater problem. And it was this distraction that became more and more marked with increasing age.

The study is a follow-up to a smaller 2014 study that included two experiments: a lab experiment involving 21 young adults, and data from the same smartphone game involving only the younger cohort (18-29 years; 3247 participants).

This study demonstrated that distraction during encoding and distraction during delay were independent contributory factors to WMC, suggesting that separate mechanisms are involved in filtering out distraction at encoding and maintenance.

Interestingly, analysis of the data from the smartphone game did indicate some correlation between the two in that context. One reason may be that participants in the smartphone game were exposed to higher load trials (the lab study kept WM load constant); another might be that they were in more distracting environments.

While in general researchers have till now assumed that the two processes are not distinct, it has been theorized that distractor filtering at encoding may involve a 'selective gating mechanism', while filtering during WM maintenance may involve a shutting down of perception. The former has been linked to a gating mechanism in the striatum in the basal ganglia, while the latter has been linked to an increase in alpha waves in the frontal cortex, specifically, the left middle frontal gyrus. The dorsolateral prefrontal cortex may also be involved in distractor filtering at encoding.

To return to the more recent study:

• there was a significant decrease in WMC with increasing age in all conditions (no distraction; encoding distraction; delay distraction)
• for older adults, the decrease in WMC was greatest in the delay distraction condition
• when 'distraction cost' was calculated (((ND score − (ED or DD score))/ND score) × 100), there was a significant correlation between delay distraction cost and age, but not between encoding distraction cost and age
• for older adults, performance in the encoding distraction condition was better predicted by performance in the no distraction condition than it was among the younger groups
• this correlation was significantly different between the 30-39 age group and the 40-49 age group, between the 40s and the 50s, and between the 50s and the 60s — showing that this is a progressive change
• older adults with a higher delay distraction cost (ie, those more affected by distractors during delay) also showed a significantly greater correlation between their no-distraction performance and encoding-distraction performance.

All of this suggests that older adults are focusing more attention during attention even when there is no distraction, and they are doing so to compensate for their reduced ability to maintain information in working memory.

This suggests several approaches to improving older adults' ability to cope:

• use perceptual discrimination training to help improve WMC
• make working memory training more about learning to ignore certain types of distraction
• reduce distraction — modify daily tasks to make them more "older adult friendly"
• (my own speculation) use meditation training to improve frontal alpha rhythms.

You can participate in the game yourself, at http://thegreatbrainexperiment.com/

http://medicalxpress.com/news/2015-05-smartphone-reveals-older.html