News reports of research into memory February 2006

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February 2006

Review supports link between lifestyle factors and cognitive function in older adults

A review of 96 papers involving 36 very large, ongoing epidemiological studies in North America and Europe looking at factors involved in maintaining cognitive and emotional health in adults as they age has concluded that controlling cardiovascular risk factors, such as reducing blood pressure, reducing weight, reducing cholesterol, treating (or preferably avoiding) diabetes, and not smoking, is important for maintaining brain health as we age. The link between hypertension and cognitive decline was the most robust across studies. They also found a consistent close correlation between physical activity and brain health. However, they caution that more research is needed before specific recommendations can be made about which types of exercise and how much exercise are beneficial. They also found protective factors most consistently reported for cognitive health included higher education level, higher socio-economic status, emotional support, better initial performance on cognitive tests, better lung capacity, more physical exercise, moderate alcohol use, and use of vitamin supplements. Psychosocial factors, such as social disengagement and depressed mood, are associated with both poorer cognitive and emotional health in late life. Increased mental activity throughout life, such as learning new things, may also benefit brain health.
The review was published in the January issue of Alzheimer's & Dementia. Full reference
http://www.eurekalert.org/pub_releases/2006-02/aa-nss021606.php

Memory problems at menopause

Findings from a study of 24 women approaching menopause have confirmed an earlier study involving over 800 women that found such women are no more likely than anyone else to suffer from memory retrieval problems. However, they did find that the women who complained more about problems with forgetfulness had a harder time learning or "encoding" new information, although they didn’t have actually have an impaired ability to learn new information. Although a larger study is needed to explore this link in more detail, the researchers suggest that stress and emotional upheaval may be responsible for attention failures that mean information isn’t encoded. The researchers did find that most of the women in their study had some sort of mood distress, including symptoms of depression or anxiety (note that this was not a random group, but women who were worried about their memory).
The study was reported at the annual meeting of the International Neuropsychological Society in Boston.
http://www.eurekalert.org/pub_releases/2006-02/uorm-mpa020206.php

Brain still developing at age 18

In a study of 19 freshman college students, it’s been found that, anatomically, significant changes in brain structure continue after age 18. The changes were localized to regions of the brain known to integrate emotion and cognition — specifically, areas that take information from our current body state and apply it for use in navigating the world (right midcingulate, inferior anterior cingulate gyrus, right caudate head, right posterior insula, and bilateral claustrum).
The study appeared online on November 29, 2005, and will appear in a forthcoming issue of Human Brain Mapping. Full reference
http://www.eurekalert.org/pub_releases/2006-02/dc-bcs020606.php

Why older adults more vulnerable to distraction from irrelevant information

We know older adults find it harder to filter out irrelevant information. Now astudy looking at brain function in young, middle-aged and older adults has identified changes in brain activity that begin gradually in middle age which may explain why. In younger adults, activity in the dorsolateral prefrontal cortex (associated with tasks that require concentration, such as reading) normally increases during the task, while activity in the medial frontal and parietal regions (associated with non-task related activity in a resting state, such as thinking about yourself, what you did last night, monitoring what's going on around you) normally decreases. In middle age (40-60 years), this pattern begins to break down during performance of memory tasks, although performance is not affected (but most of the participants were fairly well educated, so the finding of brain changes without accompanying behavioural changes in the middle-aged group may reflect the "protective effect" of education). Activity in the medial frontal and parietal regions stays turned on while activity in the dorsolateral prefrontal cortex decreases. The imbalance becomes more pronounced in older adults (65+), suggesting there is a gradual, age-related reduction in the ability to suspend non-task-related or "default-mode" activity and engage areas for carrying out memory tasks.
The findings are reported in the February 2006 issue of the Journal of Cognitive Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2006-02/b-oam013006.php

How emotions interfere with memory

We know emotion can interfere with cognitive processes. Now an imaging study adds to our understanding of how that occurs. Emotional images evoked strong activity in typical emotional processing regions (amygdala and ventrolateral prefrontal cortex) while simultaneously deactivating regions involved in memory processing (dorsolateral prefrontal cortex and lateral parietal cortex). The researchers also found individual differences among the subjects in their response to the images. People who showed greater activity in a brain region associated with the inhibition of response to emotional stimuli rated the emotional distracters as less distracting.
The findings appeared in the Feb. 15 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2006-02/dumc-he021506.php

Priming the brain for learning

A new study has revealed that how successfully you form memories depends on your frame of mind beforehand. If your brain is primed to receive information, you will have less trouble recalling it later. Moreover, researchers could predict how likely the participant was to remember a word by observing brain activity immediately prior to presentation of the word.
The study was published online 26 February ahead of print in Nature. Full reference
http://www.nature.com/news/2006/060220/full/060220-19.html
http://www.eurekalert.org/pub_releases/2006-02/uoc--uri022806.php
http://www.eurekalert.org/pub_releases/2006-02/ucl-ywr022206.php

A single memory is processed in three separate parts of the brain

A rat study has demonstrated that a single experience is indeed processed differently in separate parts of the brain. They found that when the rats were confined in a dark compartment of a familiar box and given a mild shock, the hippocampus was involved in processing memory for context, while the anterior cingulate cortex was responsible for retaining memories involving unpleasant stimuli, and the amygdala consolidated memories more broadly and influenced the storage of both contextual and unpleasant information.
The results were published February 7 in the early online edition of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2006-02/uoc--urp020106.php

Reactivating single memory does not affect associated memories

Recent studies have indicated that consolidated memories can in fact be manipulated when reactivated. This process, often referred to as reconsolidation, has been proposed as a possible way of treating traumatic memories. But one concern is that reactivating and disrupting a single memory may also affect other associated memories. A new rat study has found that only those memories directly reactivated are vulnerable, not those associated to them.
The study appeared in the February 28 issue of the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2006-02/nyu-nrs021306.php

Resting after new learning may not be laziness

In an intriguing rat study, researchers recorded brain activity while rats ran up and down a straight 1.5-metre run. As the rats ran along the track, the nerve cells fired in a very specific sequence. But to the researchers’ surprise, when the rats were resting, the same brain cells replayed the sequence of electrical firing over and over, but in reverse and speeded up. This is similar to the replay that occurs during sleep and consolidates spatial memory, but the reverse aspect has not been seen before, and is presumed to have something to do with reinforcing the sequence. The researchers suggest this may have general implications.
The study was published online 12 February ahead of print in Nature. Full reference
http://www.nature.com/news/2006/060206/full/060206-13.html

Protein that controls how neurons change as a result of experience

Two different research teams have identified a master protein that sheds light on one of neurobiology's biggest mysteries-how neurons change as a result of individual experiences. The protein, myocyte enhancer factor 2 (MEF2), turns on and off genes that control dendritic remodeling, that is the growth and pruning of neurons. In addition, one of the teams has identified how MEF2 switches from one program to the other, that is, from dendrite-promoting to dendrite-pruning, and the researchers have identified some of MEF2's targets. It’s suggested the MEF2 pathway could play a role in autism and other neurodevelopmental diseases, and this discovery could lead to new therapies for a host of diseases in which synapses either fail to form or run rampant.
The research appeared in two papers in the February 17 issue of Science. Full reference 2
http://www.eurekalert.org/pub_releases/2006-02/hms-rfm022106.php