stress

Menopause ‘brain fog’ a product of poor sleep and depression?

May, 2012

A smallish study of women approaching and in menopause found that some experienced poorer working memory and attention, and these were more likely to have poorer sleep, depression, and anxiety.

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).

What this suggests to me is that a primary cause of these cognitive impairments may be poor sleep, and anxiety/depression. A few years ago, I reported on a study that found that, although women’s reports of how many hot flashes they had didn’t correlate with memory impairment, an objective measure of the number of flashes they experienced during sleep did. Sleep, as I know from personal experience, is of sufficient importance that my rule-of-thumb is: don’t bother looking for any other causes of attention and memory deficits until you have sorted out your sleep!

Having said that, depressive symptoms showed greater relationship to memory complaints than sleep disturbance.

It’s no big surprise to hear that it is working memory in particular that is affected, because what many women at this time of life complain of is ‘brain fog’ — the feeling that your brain is full of cotton-wool. This doesn’t mean that you can’t learn new information, or remember old information. But it does mean that these tasks will be impeded to the extent that you need to hold on to too many bits of information. So mental arithmetic might be more difficult, or understanding complex sentences, or coping with unexpected disruptions to your routine, or concentrating on a task for a long time.

These sorts of problems are typical of those produced by on-going sleep deprivation, stress, and depression.

One caveat to the findings is that the study participants tended to be of above-average intelligence and education. This would protect them to a certain extent from cognitive decline — those with less cognitive reserve might display wider impairment. Other studies have found verbal memory, and processing speed, impaired during menopause.

Note, too, that a long-running, large population study has found no evidence for a decline in working memory, or processing speed, in women as they pass through perimenopause and menopause.

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Poverty-related stress affects cognitive ability

November, 2011

Stress in the lives of young children from low-income homes negatively affects their executive function and IQ, and these associations are mediated through parenting behavior and household risk.

The study involved 1,292 children followed from birth, whose cortisol levels were assessed at 7, 15, and 24 months. Three tests related to executive functions were given at age 3. Measures of parenting quality (maternal sensitivity, detachment, intrusiveness, positive regard, negative regard, and animation, during interaction with the child) and household environment (household crowding, safety and noise levels) were assessed during the home visits.

Earlier studies have indicated that a poor environment in and of itself is stressful to children, and is associated with increased cortisol levels. Interestingly, in one Mexican study, preschool children in poor homes participating in a conditional cash transfer scheme showed reduced cortisol levels.

This study found that children in lower-income homes received less positive parenting and had higher levels of cortisol in their first two years than children in slightly better-off homes. Higher levels of cortisol were associated with lower levels of executive function abilities, and to a lesser extent IQ, at 3 years.

African American children were more affected than White children on every measure. Cortisol levels were significantly higher; executive function and IQ significantly lower; ratings of positive parenting significantly lower and ratings of negative parenting significantly higher. Maternal education was significantly lower, poverty greater, homes more crowded and less safe.

The model derived from this data shows executive function negatively predicted by cortisol, while the effect on IQ is marginal. However, both executive function and IQ are predicted by negative parenting, positive parenting, and household risk (although this last variable has a greater effect on IQ than executive function). Neither executive function nor IQ was directly predicted by maternal education, ethnicity, or poverty level. Cortisol level was inversely related to positive parenting, but was not directly related to negative parenting or household risk.

Indirectly (according to this best-fit model), poverty was related to executive function through negative parenting; maternal education was related to executive function through negative parenting and to a lesser extent positive parenting; both poverty and maternal education were related to IQ through positive parenting, negative parenting, and household risk; African American ethnicity was related to executive function through negative parenting and positive parenting, and to IQ through negative parenting, positive parenting, and household risk. Cortisol levels were higher in African American children and this was unrelated to poverty level or maternal education.

Executive function (which includes working memory, inhibitory control, and attention shifting) is vital for self-regulation and central to early academic achievement. A link between cortisol level and executive function has previously been shown in preschool children, as well as adults. The association partly reflects the fact that stress hormone levels affect synaptic plasticity in the prefrontal cortex, where executive functions are carried out. This is not to say that this is the only brain region so affected, but it is an especially sensitive one. Chronic levels of stress alter the stress response systems in ways that impair flexible regulation.

What is important about this study is this association between stress level and cognitive ability at an early age, that the effect of parenting on cortisol is associated with positive aspects rather than negative ones, and that the association between poverty and cognitive ability is mediated by both cortisol and parenting behavior — both positive and negative aspects.

A final word should be made on the subject of the higher cortisol levels in African Americans. Because of the lack of high-income African Americans in the sample (a reflection of the participating communities), it wasn’t possible to directly test whether the effect is accounted for by poverty. So this remains a possibility. It is also possible that there is some genetic difference. But it also might reflect other sources of stress, such as that relating to prejudice and stereotype threat.

Based on mother’s ethnic status, 58% of the families were Caucasian and 42% African American. Two-thirds of the participants had an income-to-need ratio (estimated total household income divided by the 2005 federal poverty threshold adjusted for number of household members) less than 200% of poverty. Just over half of the mothers weren’t married, and most of them (89%) had never been married. The home visits at 7, 15, and 24 months lasted at least an hour, and include a videotaped free play or puzzle completion interaction between mother and child. Cortisol samples were taken prior to an emotion challenge task, and 20 minutes and 40 minutes after peak emotional arousal.

Long-term genetic effects of childhood environment

The long-term effects of getting off to a poor start are deeper than you might believe. A DNA study of forty 45-year-old males in a long-running UK study has found clear differences in gene methylation between those who experienced either very high or very low standards of living as children or adults (methylation of a gene at a significant point in the DNA reduces the activity of the gene). More than twice as many methylation differences were associated with the combined effect of the wealth, housing conditions and occupation of parents (that is, early upbringing) than were associated with the current socio-economic circumstances in adulthood (1252 differences as opposed to 545).

The findings may explain why the health disadvantages known to be associated with low socio-economic position can remain for life, despite later improvement in living conditions. The methylation profiles associated with childhood family living conditions were clustered together in large stretches of DNA, which suggests that a well-defined epigenetic pattern is linked to early socio-economic environment. Adult diseases known to be associated with early life disadvantage include coronary heart disease, type 2 diabetes and respiratory disorders.

Reference: 

[2589] Blair, C., Granger D. A., Willoughby M., Mills-Koonce R., Cox M., Greenberg M. T., et al.
(2011).  Salivary Cortisol Mediates Effects of Poverty and Parenting on Executive Functions in Early Childhood.
Child Development. no - no.

Fernald, L. C., & Gunnar, M. R. (2009). Poverty-alleviation program participation and salivary cortisol in very low-income children. Social Science and Medicine, 68, 2180–2189.

[2590] Borghol, N., Suderman M., McArdle W., Racine A., Hallett M., Pembrey M., et al.
(2011).  Associations with early-life socio-economic position in adult DNA methylation.
International Journal of Epidemiology.

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What transient amnesia tells us about autobiographical memory and brain plasticity

November, 2011
  • Brain scans of those suffering from transient global amnesia indicate a permanent role of the hippocampus in autobiographical memory, and demonstrate the brain’s ability to self-repair.

When a middle-aged woman loses her memory after sex, it naturally makes the headlines. Many might equate this sort of headline to “Man marries alien”, but this is an example of a rare condition — temporary, you will be relieved to hear — known as transient global amnesia. Such abrupt, localized loss of autobiographical memory is usually preceded by strenuous physical activity or stressful events. It generally occurs in middle-aged or older adults, but has been known to occur in younger people. In those cases, there may be a history of migraine or head trauma.

Following an earlier study in which 29 of 41 TGA patients were found to have small lesions in the CA1 region of the hippocampus, scanning of another 16 TGA patients has revealed 14 had these same lesions. It seems likely that all the patients had such lesions, but because they are very small and don’t last long, they’re easy to miss. The lesion is best seen after 24-72 hours, but is gone after 5-6 days.

At the start of one of these attacks, memory for the first 30 years of life was significantly impaired, but still much better than memory for the years after that. There was a clear temporal gradient, with memory increasingly worse for events closer in time. There was no difference between events in the previous year and events in the previous five years, but a clear jump at that five-year point.

The exact location of the lesions was significant: when the lesion was in the anterior part of the region, memory for recent events was more impaired.

The hippocampus is known to be crucially involved in episodic memory (memory for events), and an integral part of the network for autobiographical memory. In recent years, it has come to be thought that such memories are only hosted temporarily by the hippocampus, and over a few years come to be permanently lodged in the neocortex (the standard consolidation model). Evidence from a number of studies of this change at the five-year mark has been taken as support for this theory. According to this, then, older memories should be safe from hippocampal damage.

An opposing theory, however, is that the hippocampus continues to be involved in such memories, with both the neocortex and the hippocampus involved in putting together reconsolidated memories (the multiple trace model). According to this model, each retrieval of an episodic memory creates a new version in the hippocampus. The more versions, the better protected a memory will be from any damage to the hippocampus.

The findings from this study show that while there is indeed a significant difference between older and more recent memories, the CA1 region of the hippocampus continues to be crucial for retrieving older memories, and for our sense of self-continuity.

Interestingly, some studies have also found a difference between the left and right hemispheres, with the right hippocampus showing a temporal gradient and the left hippocampus showing constant activation across all time periods. Such a hemisphere difference was not found in the present study. The researchers suggest that the reason may lie in the age of the participants (average age was 68), reflecting a reduction in hemispheric asymmetry with age.

There’s another message in this study. In these cases of TGA, memory function is restored within 24 hours (and generally sooner, within 6-10 hours). This shows how fast the brain can repair damage. Similarly, the fact that such tiny lesions have temporary effects so much more dramatic than the more lasting effects of larger lesions, is also a tribute to the plasticity of the brain.

The findings are consistent with findings of a preferential degeneration of CA1 neurons in the early stages of Alzheimer's disease, and suggest a target for treatment.

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Emotion

Older news items (pre-2010) brought over from the old website

How emotion affects memory (general)

Mixed feelings not remembered as well as happy or sad ones

A series of studies that tested participants' emotions when they faced scenarios such as taking tests and moving, events that are typically associated with mixed emotions, has found that the intensity of mixed emotions tends to be underestimated when recalling the experience. This underestimation increases over time, to the point that people sometimes don't remember having felt ambivalent at all. This is more likely among those who are uncomfortable feeling mixed emotions. Interestingly, Asian Americans in the study did not exhibit the same degree of memory decline for mixed emotions as Anglo-Americans did.

Aaker, J., Drolet, A. & Griffin, D. 2008. Recalling Mixed Emotions. Journal of Consumer Research, 35 (2), 268-278.

http://www.eurekalert.org/pub_releases/2008-06/uocp-mfn062508.php

Emotions help memory, at the cost of other memories

Do we remember emotionally charged events better? Maybe — but at a price. A new study presented volunteers with lists of neutral words with one disturbing noun, such as murder or scream, embedded. As expected, the emotional words were much better remembered than the neutral words. More interestingly, the poorest memory occurred for neutral words that were presented immediately before the disturbing words. The effect was greater for women — women forgot those words twice as often as men.

[214] Strange, B. A., Hurlemann R., & Dolan R. J.
(2003).  An emotion-induced retrograde amnesia in humans is amygdala- and beta-adrenergic-dependent.
Proceedings of the National Academy of Sciences of the United States of America. 100(23), 13626 - 13631.

http://www.sciencenews.org/20031108/fob5.asp

How memory helps make life pleasant

Surveys consistently show that people are generally happy with their lives. A review of research into autobiographical memory suggests why - human memory is biased toward happiness. Across 12 studies conducted by five different research teams, people of different racial and ethnic backgrounds and of different ages consistently reported experiencing more positive events in their lives than negative events, suggesting that pleasant events do in fact outnumber unpleasant events because people seek out positive experiences and avoid negative ones. Our memory also treats pleasant emotions differently from unpleasant emotions. Pleasant emotions appear to fade more slowly from our memory than unpleasant emotions. This is not repression; people do remember negative events, they just remember them less negatively. Among those with mild depression, however, unpleasant and pleasant emotions tend to fade evenly.

Walker, W.R., Skowronski, J.J. & Thompson, C.P. 2003. Life Is Pleasant -- and Memory Helps to Keep It That Way! Review of General Psychology, 7(2),203-10.

http://www.eurekalert.org/pub_releases/2003-06/apa-rtg060203.php

Suppressing your expression of emotion affects your memory for the event

The way people go about controlling their reactions to emotional events affects their memory of the event. In a series of experiments designed to assess the effect of suppressing the expression of emotion, it was found that, when people were shown a video of an emotional event and instructed not to let their emotions show, they had poorer memory for what was said and done than did those people who were given no such instructions. However, when shown slides of people who had been injured, people in both groups were equally good at picking which in an array of subtly different versions of each slide had been shown earlier - but when prompted to recall information that had been presented verbally with each slide, those in the suppression group again remembered fewer details. People who were asked to adopt the neutral attitude of a medical profession however, performed better than the control group on nonverbal recall, indicating the regulation of emotions via reappraisal was not associated with any memory impairment. These experimental results were supported by a naturalistic study.

[607] Richards, J. M., & Gross J. J.
(2000).  Emotion regulation and memory: The cognitive costs of keeping one's cool..
Journal of Personality and Social Psychology. 79(3), 410 - 424.

http://www.sciencedaily.com/releases/2000/09/000913203335.htm

Mood

When mood affects memory

The effect of mood on memory depends on what questions are asked; only some aspects of memory are affected by incidental mood. For example, your memory of a restaurant's food won't be affected by the mood you were in when you ate it, but your memory of how much you enjoyed it will be. A new study shows that the effects of mood also depend on whether you had thought about that aspect during the experience — whether you had thought about how enjoyable the experience was at the time. In the study, people were shown a painting. Half of them were first put in a negative mood by reading and answering questions about an unpleasant subject. After looking at the painting, half were asked what they thought of it. Five days later, the participants were all asked how much they had liked the painting. While being in a negative mood had affected those who had evaluated the painting at the time, it did not affect those who had not made an evaluation at the time of presentation.

Pocheptsova, A. & Novemsky, N. 2009. When Do Incidental Mood Effects Last? Lay Beliefs versus Actual Effects. Journal of Consumer Research, Published online September 10, 2009

http://www.physorg.com/news172767544.html
http://www.eurekalert.org/pub_releases/2009-09/uocp-mmn092109.php

Perception affected by mood

An imaging study has revealed that when people were shown a composite image with a face surrounded by "place" images, such as a house, and asked to identify the gender of the face, those in whom a bad mood had been induced didn’t process the places in the background. However, those in a good mood took in both the focal and background images. These differences in perception were coupled with differences in activity in the parahippocampal place area. Increasing the amount of information is of course not necessarily a good thing, as it may result in more distraction.

[1054] Schmitz, T. W., De Rosa E., & Anderson A. K.
(2009).  Opposing Influences of Affective State Valence on Visual Cortical Encoding.
J. Neurosci.. 29(22), 7199 - 7207.

http://www.eurekalert.org/pub_releases/2009-06/uot-pww060309.php

Positive mood may not help in tasks requiring attention to detail

A series of experiments with different child age groups who had happy or sad moods induced with the aid of music and selected video clips before then being asked to undertake a task that required attention to detail has found that the children induced to feel a sad or neutral mood performed the task better than those induced to feel happy. Other research has found that a positive mood is beneficial in other situations, such as when a task calls for creative thinking.

[854] Schnall, S. [1], Jaswal V. K. [2], & Rowe C. [1]
(2008).  A hidden cost of happiness in children.
Developmental Science. 11, F25-F30 - F25-F30.

http://www.eurekalert.org/pub_releases/2008-06/uov-ssc053008.php

Omega-3 boosts grey matter

A study of 55 healthy adults has found that those who had high levels of long-chain omega-3 fatty acids had more gray matter in areas of the brain associated with emotional arousal and regulation — the bilateral anterior cingulate cortex, the right amygdala and the right hippocampus. Although this doesn’t mean omega-3 necessarily causes such changes, the finding does support a recent study that found higher levels of omega-3 were associated with a more positive outlook, and animal studies showing that increasing omega-3 intake leads to structural changes in the brain. Good sources of omega-3 fatty acids are walnuts, flax, and fatty fish such as salmon and sardines.

The findings were presented March 7 at the American Psychosomatic Society's Annual Meeting, in Budapest, Hungary.

http://www.sciencedaily.com/releases/2007/03/070307080827.htm
http://www.webmd.com/diet/news/20070307/omega-3-fatty-acids-may-boost-brain

Insight into the processes of 'positive' and 'negative' learners

An intriguing study of the electrical signals emanating from the brain has revealed two types of learners. A brainwave event called an "event-related potential" (ERP) is important in learning; a particular type of ERP called "error-related negativity" (ERN), is associated with activity in the anterior cingulate cortex. This region is activated during demanding cognitive tasks, and ERNs are typically more negative after participants make incorrect responses compared to correct choices. Unexpectedly, studies of this ERN found a difference between "positive" learners, who perform better at choosing the correct response than avoiding the wrong one, and "negative" learners, who learn better to avoid incorrect responses. The negative learners showed larger ERNs, suggesting that "these individuals are more affected by, and therefore learn more from, their errors.” Positive learners had larger ERNs when faced with high-conflict win/win decisions among two good options than during lose/lose decisions among two bad options, whereas negative learners showed the opposite pattern.

[818] Frank, M. J., Woroch B. S., & Curran T.
(2005).  Error-Related Negativity Predicts Reinforcement Learning and Conflict Biases.
Neuron. 47(4), 495 - 501.

http://www.eurekalert.org/pub_releases/2005-08/cp-iit081205.php

Positive emotions help people see big picture details

A study involving 89 students, who watched a video designed to induce either joy and laughter, anxiety, or no emotion, found that those who were in a positive mood had a far greater ability to recognize members of another race when briefly shown photos of individuals. In the absence of positive emotions, subjects recognized members of their own race 75% of the time but only recognized members of another race 65% of the time. Their ability to recognize members of their own race was unaffected by their emotional state.

[2551] Johnson, K. J., & Fredrickson B. L.
(2005).  “We All Look the Same to Me”.
Psychological Science. 16(11), 875 - 881.

http://www.eurekalert.org/pub_releases/2005-02/uom-pes020105.php

Mood affects eyewitness accuracy and reasoning

A new study suggests people in a negative mood provide more accurate eyewitness accounts than people in a positive mood state. Moreover, people in a positive mood showed poorer judgment and critical thinking skills than those in a negative mood. The researchers suggest that a negative mood state triggers more systematic and attentive, information processing, while good moods signal a benign, non-threatening environment where we don't need to be so vigilant.

[2550] Forgas, J. P., Laham S. M., & Vargas P. T.
(2005).  Mood effects on eyewitness memory: Affective influences on susceptibility to misinformation.
Journal of Experimental Social Psychology. 41(6), 574 - 588.

http://www.eurekalert.org/pub_releases/2004-08/uons-era082004.php

Excitement helps memory for unrelated events

We’ve long known that emotionally charged events are easier to remember than boring ones. New research suggests that the reason is the flood of emotion, not the personal meaningfulness of the event. Subjects asked to memorize a list of words did better if they subsequently watched a gory film of a bloody dental extraction, rather than a dull video on tooth brushing.

Nielson, K.A., Yee, D. & Erickson, K.I. 2002. Modulation of memory storage processes by post-training emotional arousal from a semantically unrelated source. Paper presented at the Society for Neuroscience annual meeting in Orlando, Florida, 4 November.

http://www.nature.com/nsu/021104/021104-5.html

Mood needs to be matched to cognitive task for best performance

An imaging study looked at the brain activity of 14 college-aged men and women as they performed difficult cognitive tasks requiring the active retention of information in working memory, after watching short, emotional videos, designed to elicit one of three emotional states: pleasant, neutral or anxious. It was found that mild anxiety improved performance on some tasks, but hurt performance on others. Being in a pleasant mood boosted some kinds of performance but impaired other kinds. A region of the prefrontal cortex was jointly influenced by a combination of mood state and cognitive task, but not by either one alone.

[227] Gray, J. R., Braver T. S., & Raichle M. E.
(2002).  Integration of emotion and cognition in the lateral prefrontal cortex.
Proceedings of the National Academy of Sciences of the United States of America. 99(6), 4115 - 4120.

http://www.eurekalert.org/pub_releases/2002-03/wuis-mlt031802.php

Brain study shows how surprises help us learn

Because they are hard to forget, surprises can help us learn. Now scientists have identified a part of the brain that may be involved in learning from surprises. A team led by Dr. Paul C. Fletcher at the University of Cambridge monitored the brain activity in a group of volunteers who were participating in a simulation exercise. The participants pretended to work at drug companies and were asked to predict whether a particular fictitious drug would trigger a particular fictitious syndrome. In the early phase of the study, when the participants were not familiar with the effects of the various drugs, imaging tests detected high levels of activity in this part of the brain. As the volunteers became familiar with the effects of the drugs, so that they were no longer surprised by the results, activity in the dorsolateral prefrontal cortex declined, but later in the study, this region became more active when the participants were surprised by unexpected responses.

[1329] Fletcher, P. C., Anderson J. M., Shanks D. R., Honey R., Carpenter T. A., Donovan T., et al.
(2001).  Responses of human frontal cortex to surprising events are predicted by formal associative learning theory.
Nat Neurosci. 4(10), 1043 - 1048.

Motivation & attitude

Confidence as important as IQ in exam success

I’ve talked repeatedly about the effects of self-belief on memory and cognition. One important area in which this is true is that of academic achievement. Evidence indicates that your perceived abilities matter, just as much? more than? your actual abilities. It has been assumed that self perceived abilities, self-confidence if you will, is a product mainly of nurture. Now a new twin study provides evidence that nurture / environment may only provide half the story; the other half may lie in the genes. The study involved 1966 pairs of identical twins and 1877 pairs of fraternal twins. The next step is to tease out which of these genes are related to IQ and which to personality variables.

[1080] Greven, C. U., Harlaar N., Kovas Y., Chamorro-Premuzic T., & Plomin R.
(2009).  More Than Just IQ: School Achievement Is Predicted by Self-Perceived Abilities—But for Genetic Rather Than Environmental Reasons.
Psychological Science. 20(6), 753 - 762.

http://www.newscientist.com/article/dn17187-confidence-as-important-as-iq-in-exam-success.html

Anticipation strengthens memory

An imaging study has revealed that the amygdala and the hippocampus become activated when a person is anticipating a difficult situation (some type of gruesome picture). Moreover, the higher the level of activation during this anticipation, the better the pictures were remembered two weeks later. The study demonstrates how expectancy can affect long-term memory formation, and suggests that the greater our anxiety about a situation, the better we’ll remember that situation. If it’s an unpleasant one, this will only reinforce the anxiety, setting up a vicious cycle. The study has important implications for the treatment of psychological conditions such as post-traumatic stress disorder and social anxiety.

[354] Mackiewicz, K. L., Sarinopoulos I., Cleven K. L., & Nitschke J. B.
(2006).  The effect of anticipation and the specificity of sex differences for amygdala and hippocampus function in emotional memory.
Proceedings of the National Academy of Sciences. 103(38), 14200 - 14205.

http://www.eurekalert.org/pub_releases/2006-09/uow-apa090106.php

Why motivation helps memory

An imaging study has identified the brain region involved in anticipating rewards — specific brain structures in the mesolimbic region involved in the processing of emotions — and revealed how this reward center promotes memory formation. Cues to high-reward scenes that were later remembered activated the reward areas of the mesolimbic region as well as the hippocampus. Anticipatory activation also suggests that the brain actually prepares in advance to filter incoming information rather than simply reacting to the world.

[1254] Adcock, A. R., Thangavel A., Whitfield-Gabrieli S., Knutson B., & Gabrieli J. D. E.
(2006).  Reward-Motivated Learning: Mesolimbic Activation Precedes Memory Formation.
Neuron. 50(3), 507 - 517.

http://www.eurekalert.org/pub_releases/2006-05/cp-tbm042706.php

Different brain regions for arousing and non-arousing words

An imaging study has found that words representing arousing events (e.g., “rape”, “slaughter”) activate cells in the amygdala, while nonarousing words (e.g., “sorrow”, “mourning”) activated cells in the prefrontal cortex. The hippocampus was active for both type of words. On average, people remembered more of the arousing words than the others, suggesting stress hormones, released as part of the response to emotionally arousing events, are responsible for enhancing memories of those events.

Kensinger, E.A. & Corkin, S. 2004. Two routes to emotional memory: Distinct neural processes for valence and arousal. PNAS, 101, 3310-3315. Published online before print February 23 2004, 10.1073/pnas.0306408101

http://www.eurekalert.org/pub_releases/2004-03/miot-mlu030104.php

 

Gender & age effects

When emotions involved, older adults may perform memory tasks better than young adults

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.

[200] 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.

http://www.eurekalert.org/pub_releases/2009-03/giot-oac030409.php

Aging brains allow negative memories to fade

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.

[680] 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.

http://www.eurekalert.org/pub_releases/2008-12/uoaf-aba121608.php
http://www.eurekalert.org/pub_releases/2008-12/dumc-oay121508.php

Emotions help memory, at the cost of other memories

Do we remember emotionally charged events better? Maybe — but at a price. A new study presented volunteers with lists of neutral words with one disturbing noun, such as murder or scream, embedded. As expected, the emotional words were much better remembered than the neutral words. More interestingly, the poorest memory occurred for neutral words that were presented immediately before the disturbing words. The effect was greater for women — women forgot those words twice as often as men.

[214] Strange, B. A., Hurlemann R., & Dolan R. J.
(2003).  An emotion-induced retrograde amnesia in humans is amygdala- and beta-adrenergic-dependent.
Proceedings of the National Academy of Sciences of the United States of America. 100(23), 13626 - 13631.

http://www.sciencenews.org/20031108/fob5.asp

Why women better remember emotional memories

A new brain imaging study reveals gender differences in the encoding of emotional memories. We have long known that women are better at remembering emotional memories, now we can see that the sexes tend to encode emotional experiences in different parts of the brain. In women, it seems that evaluation of emotional experience and encoding of the memory is much more tightly integrated.

[807] Canli, T., Desmond J. E., Zhao Z., & Gabrieli J. D. E.
(2002).  Sex differences in the neural basis of emotional memories.
Proceedings of the National Academy of Sciences of the United States of America. 99(16), 10789 - 10794.

http://www.newscientist.com/news/news.jsp?id=ns99992576

Older adults better at forgetting negative images

It seems that this general tendency, to remember the good, and let the bad fade, gets stronger as we age. Following recent research suggesting that older people tend to regulate their emotions more effectively than younger people, by maintaining positive feelings and lowering negative feelings, researchers examined age differences in recall of positive, negative and neutral images of people, animals, nature scenes and inanimate objects. The first study tested 144 participants aged 18-29, 41-53 and 65-80. Older adults recalled fewer negative images relative to positive and neutral images. For the older adults, recognition memory also decreased for negative pictures. As a result, the younger adults remembered the negative pictures better. Preliminary brain research suggests that in older adults, the amygdala is activated equally to positive and negative images, whereas in younger adults, it is activated more to negative images. This suggests that older adults encode less information about negative images, which in turn would diminish recall.

[343] Charles, S T., Mather M., & Carstensen L. L.
(2003).  Aging and Emotional Memory: The Forgettable Nature of Negative Images for Older Adults.
Journal of Experimental Psychology: General. 132(2), 310 - 324.

http://www.apa.org/releases/aging_memory.html

Gender & race stereotypes

Neurology

Nasal spray boosts consolidation of emotional memory

A study in which 17 healthy young men were given a nasal spray of either interleukin-6 or a placebo after reading a short story (emotional on one occasion; neutral on the other) before going to bed, has found that those given the immune system molecule showed improved memory for emotional text (but not other kinds of material). Interleukin-6 is involved in inflammatory responses, but recently has also been implicated in memory consolidation during sleep. This finding supports that role, and demonstrates an interaction between the immune system and the central nervous system.

[811] Benedict, C., Scheller J., Rose-John S., Born J., & Marshall L.
(2009).  Enhancing influence of intranasal interleukin-6 on slow-wave activity and memory consolidation during sleep.
FASEB J.. 23(10), 3629 - 3636.

http://www.sciencedaily.com/releases/2009/10/091001091752.htm

Sleep selectively preserves emotional memories

It’s now generally accepted that sleep plays an important role in consolidating procedural (skill) memories, but the position regarding other types of memory has been less clear.  A new study has found that sleep had an effect on emotional aspects of a memory. The study involved showing 88 students neutral scenes (such as a car parked on a street in front of shops) or negative scenes (a badly crashed car parked on a similar street). They were then tested for their memories of both the central objects in the pictures and the backgrounds in the scenes, either after 12 daytime hours, or 12 night-time hours, or 30 minutes after viewing the images, in either the morning or evening.  Those tested after 12 daytime hours largely forgot the entire negative scene, forgetting both the central objects and the backgrounds equally. But those tested after a night’s sleep remembered the emotional item (e.g., the smashed car) as well as those who were tested only 30 minutes later. Their memory of the neutral background was however, as bad as the daytime group. The findings are consistent with the view that the individual components of emotional memory become 'unbound' during sleep, enabling the brain to selectively preserve only that information it considers important.

[875] Payne, J. D., Stickgold R., Swanberg K., & Kensinger E. A.
(2008).  Sleep preferentially enhances memory for emotional components of scenes.
Psychological Science: A Journal of the American Psychological Society / APS. 19(8), 781 - 788.

http://www.physorg.com/news137908693.html
http://www.eurekalert.org/pub_releases/2008-08/bidm-sft081308.php

Why emotion enhances memory

We know that emotion can increase the memorability of events, but we haven’t known exactly why it does so. Now a new study reveals that during emotional arousal, the stress hormone norepinephrine makes synapses dramatically more sensitive by increasing the number of GluR1 receptors.

[423] Hu, H., Real E., Takamiya K., Kang M-G., Ledoux J., Huganir R. L., et al.
(2007).  Emotion Enhances Learning via Norepinephrine Regulation of AMPA-Receptor Trafficking.
Cell. 131(1), 160 - 173.

http://www.eurekalert.org/pub_releases/2007-10/jhmi-wem100407.php
http://www.eurekalert.org/pub_releases/2007-10/cp-hec100107.php
http://www.brainatlas.org/aba/2007/071018/full/aba1787.shtml

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.

[270] Dolcos, F., & McCarthy G.
(2006).  Brain Systems Mediating Cognitive Interference by Emotional Distraction.
J. Neurosci.. 26(7), 2072 - 2079.

http://www.eurekalert.org/pub_releases/2006-02/dumc-he021506.php

Different aspects of attention located in different parts of the brain

We all know attention is important, but we’ve never been sure exactly what it is. Recent research suggests there’s good reason for this – attention appears to be multi-faceted, far less simple than originally conceived. Patients with specific lesions in the frontal lobes and other parts of the brain have provided evidence that different types of attentional problems are associated with injuries in different parts of the brain, suggesting that attention is not, as has been thought, a global process. The researchers have found evidence for at least three distinct processes, each located in different parts of the frontal lobes. These are: (1) a system that helps us maintain a general state of readiness to respond, in the superior medial frontal regions; (2) a system that sets our threshold for responding to an external stimulus, in the left dorsolateral region; and (3) a system that helps us selectively attend to appropriate stimuli, in the right dorsolateral region.

[260] Stuss, D. T., Binns M. A., Murphy K. J., & Alexander M. P.
(2002).  Dissociations within the anterior attentional system: effects of task complexity and irrelevant information on reaction time speed and accuracy.
Neuropsychology. 16(4), 500 - 513.

http://www.eurekalert.org/pub_releases/2002-10/apa-pda100702.php

How emotions interfere with staying focused

In a new imaging study, Duke University researchers have shown how emotional stimuli and "attentional functions" like driving move in parallel streams through the brain before being integrated in a specific part of the brain's prefrontal cortex (the anterior cingulate, which is located between the right and left halves). Emotional stimuli are thus more likely than simple distractions to interfere with a person's efforts to focus on a task such as driving. These findings may help us understand the neural dynamics underlying emotional distractibility on attentional tasks in affective disorders.

[835] Yamasaki, H., LaBar K. S., & McCarthy G.
(2002).  Dissociable prefrontal brain systems for attention and emotion.
Proceedings of the National Academy of Sciences of the United States of America. 99(17), 11447 - 11451.

www.pnas.org/cgi/doi/10.1073/pnas.182176499
http://www.pnas.org/cgi/content/abstract/99/17/11447

Cerebellum implicated in remembering emotions

The part of the brain known as the cerebellum has been most closely associated with motor coordination skills. Experiments with rats suggest that it may also be involved in remembering strong emotions, in particular, in the consolidation of long-term memories of fear.

[763] Sacchetti, B., Baldi E., Lorenzini C A., & Bucherelli C.
(2002).  Cerebellar role in fear-conditioning consolidation.
Proceedings of the National Academy of Sciences of the United States of America. 99(12), 8406 - 8411.

http://www.pnas.org/cgi/content/abstract/112660399v1
http://news.bmn.com/jscan/biology?uid=18768

Amygdala may be critical for allowing perception of emotionally significant events despite inattention

We choose what to pay attention to, what to remember. We give more weight to some things than others. Our perceptions and memories of events are influenced by our preconceptions, and by our moods. Researchers at Yale and New York University have recently published research indicating that the part of the brain known as the amygdala is responsible for the influence of emotion on perception. This builds on previous research showing that the amygdala is critically involved in computing the emotional significance of events. The amygdala is connected to those brain regions dealing with sensory experiences, and the theory that these connections allow the amygdala to influence early perceptual processing is supported by this research. Dr. Anderson suggests that “the amygdala appears to be critical for the emotional tuning of perceptual experience, allowing perception of emotionally significant events to occur despite inattention.”

[968] Anderson, A. K., & Phelps E. A.
(2001).  Lesions of the human amygdala impair enhanced perception of emotionally salient events.
Nature. 411(6835), 305 - 309.

http://www.eurekalert.org/pub_releases/2001-05/NYU-Infr-1605101.php

tags memworks: 

The effect of stress on performance depends on individual and situational factors

September, 2011

A new study shows how stress only impacts math performance in those with both higher working memory capacity and math anxiety, while another shows that whether or not pressure impacts your performance depends on the nature of the pressure and the type of task.

Working memory capacity and level of math anxiety were assessed in 73 undergraduate students, and their level of salivary cortisol was measured both before and after they took a stressful math test.

For those students with low working memory capacity, neither cortisol levels nor math anxiety made much difference to their performance on the test. However, for those with higher WMC, the interaction of cortisol level and math anxiety was critical. For those unafraid of math, the more their cortisol increased during the test, the better they performed; but for those anxious about math, rising cortisol meant poorer performance.

It’s assumed that low-WMC individuals were less affected because their performance is lower to start with (this shouldn’t be taken as an inevitability! Low-WMC students are disadvantaged in a domain like math, but they can learn strategies that compensate for that problem). But the effect on high-WMC students demonstrates how our attitude and beliefs interact with the effects of stress. We may all have the same physiological responses, but we interpret them in different ways, and this interpretation is crucial when it comes to ‘higher-order’ cognitive functions.

Another study investigated two theories as why people choke under pressure: (a) they’re distracted by worries about the situation, which clog up their working memory; (b) the stress makes them pay too much attention to their performance and become self-conscious. Both theories have research backing from different domains — clearly the former theory applies more to the academic testing environment, and the latter to situations involving procedural skill, where explicit attention to the process can disrupt motor sequences that are largely automatic.

But it’s not as simple as one effect applying to the cognitive domain, and one to the domain of motor skills, and it’s a little mysterious why pressure could have too such opposite effects (drawing attention away, or toward). This new study carried out four experiments in order to define more precisely the characteristics of the environment that lead to these different effects, and suggest solutions to the problem.

In the first experiment, participants were given a category learning task, in which some categories had only one relevant dimension and could be distinguished according to one easily articulated rule, and others involved three relevant dimensions and one irrelevant one. Categorization in this case was based on a complex rule that would be difficult to verbalize, and so participants were expected to integrate the information unconsciously.

Rule-based category learning was significantly worse when participants were also engaged in a secondary task requiring them to monitor briefly appearing letters. However it was not affected when their secondary task involved them explicitly monitoring the categorization task and making a confidence judgment. On the other hand, the implicit category learning task was not disrupted by the letter-monitoring task, but was impaired by the confidence-judgment task. Further analysis revealed that participants who had to do the confidence-judgment task were less likely to use the best strategy, but instead persisted in trying to verbalize a one- or two-dimension rule.

In the second experiment, the same tasks were learned in a low-pressure baseline condition followed by either a low-pressure control condition or one of two high-pressure conditions. One of these revolved around outcome — participants would receive money for achieving a certain level of improvement in their performance. The other put pressure on the participants through monitoring — they were watched and videotaped, and told their performance would be viewed by other students and researchers.

Rule-based category learning was slower when the pressure came from outcomes, but not when the pressure came from monitoring. Implicit category learning was unaffected by outcome pressure, but worsened by monitoring pressure.

Both high-pressure groups reported the same levels of pressure.

Experiment 3 focused on the detrimental combinations — rule-based learning under outcome pressure; implicit learning under monitoring pressure — and added the secondary tasks from the first experiment.

As predicted, rule-based categories were learned more slowly during conditions of both outcome pressure and the distracting letter-monitoring task, but when the secondary task was confidence-judgment, the negative effect of outcome pressure was counteracted and no impairment occurred. Similarly, implicit category learning was slowed when both monitoring pressure and the confidence-judgment distraction were applied, but was unaffected when monitoring pressure was counterbalanced by the letter task.

The final experiment extended the finding of the second experiment to another domain — procedural learning. As expected, the motor task was significantly affected by monitoring pressure, but not by outcome pressure.

These findings suggest two different strategies for dealing with choking, depending on the situation and the task. In the case of test-taking, good test preparation and a writing exercise can boost performance by reducing anxiety and freeing up working memory. If you're worried about doing well in a game or giving a memorized speech in front of others, you instead want to distract yourself so you don't become focused on the details of what you're doing.

Reference: 

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Stereotype threat's effect on black students' academic achievement

August, 2011

Another study on the dramatic impact of stereotype threat on academic achievement, and how you can counter it.

In a two-part experiment, Black and White students studied the definitions of 24 obscure English words, and were later tested, in threatening or non-threatening environments. In the threatening study environment, students were told that the task would assess their "learning abilities and limitations" and "how well people from different backgrounds learn”. In the non-threatening environment, students were told that the study focused on identifying "different learning styles". When tested one to two weeks later, students were first given a low-stress warm-up exercise with half of the word definitions. Then, in order to evoke concerns about stereotypes, a test was given which was described as evaluating "your ability to learn verbal information and your performance on problems requiring verbal reasoning ability".

The effect of these different environments on the Black students was dramatic. On the non-threatening warm-up test, Black students who had studied in the threatening learning environment performed about 50% worse than Black students who had studied in the non-threatening environment. But on the ‘real’ test, for which stereotypes had been evoked, all the Blacks — including those who had done fine on the warm-up — did poorly.

In the second experiment, only Black students were involved, and they all studied in the threatening environment. This time, however, half of the students were asked to begin with a "value affirmation" exercise, during which they chose values that mattered most to them and explained why. The other students were asked to write about a value that mattered little to them. A week later, students did the warm-up and the test. Black students who had written about a meaningful value scored nearly 70% better on the warm-up than black students who had written about other values.

Reference: 

[2348] Taylor, V J., & Walton G. M.
(2011).  Stereotype Threat Undermines Academic Learning.
Personality and Social Psychology Bulletin. 37(8), 1055 - 1067.

Source: 

Topics: 

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Meditation's cognitive benefits

A critical part of attention (and working memory capacity) is being able to ignore distraction. There has been growing evidence that meditation training (in particular mindfulness meditation) helps develop attentional control, and that this can start to happen very quickly.

For example:

  • after an eight-week course that included up to 30 minutes of daily meditation, novices improved their ability to quickly and accurately move and focus attention.
  • three months of rigorous training in Vipassana meditation improved attentional control.
  • after eight weeks of Mindfulness Training, Marine reservists during pre-deployment showed increased working memory capacity and decreased negative mood (this training also included concrete applications for the operational environment and information and skills about stress, trauma and resilience in the body).
  • after a mere four sessions of 20 minutes, students produced a significant improvement in critical cognitive skills — and a dramatic improvement when conditions became more stressful (provided by increasingly challenging time-constraints).

There seem to be several factors involved in these improvements: better control of brainwaves; increased gray matter density in some brain regions; improved white-matter connectivity.

Thus, after ten weeks of Transcendental Meditation (TM) practice, students showed significant changes in brainwave patterns during meditation compared to eyes-closed rest for the controls. These changes reflected greater coherence and power in brainwave activity in areas that overlap with the default mode network (the brain’s ‘resting state’). Similarly, after an eight-week mindfulness meditation program, participants had better control of alpha brainwaves. Relatedly, perhaps, experienced Zen meditators have shown that, after interruptions designed to mimic spontaneous thoughts, they could bring activity in most regions of the default mode network back to baseline faster than non-meditators.

Thus, after an 8-week mindfulness meditation program, participants showed increased grey-matter density in the left hippocampus , posterior cingulate cortex, temporo-parietal junction , and cerebellum , as well as decreased grey-matter density in the amygdala . Similarly, another study found experienced meditators showed significantly larger volumes of the right hippocampus and the right orbitofrontal cortex, and to a lesser extent the right thalamus and the left inferior temporal gyrus.

These areas of the brain are all closely linked to emotion, and may explain meditators' improved ability in regulating their emotions.

Thus, long-term meditators showed pronounced differences in white-matter connectivity between their brains and those of age-matched controls, meaning that meditators’ brains were better able to quickly relay electrical signals. The brain regions linked by these white-matter tracts include many of those mentioned as showing increased gray matter density. Another study found that a mere 11 hours of meditation training (IBMT) produced measurable changes in the integrity and efficiency of white matter in the corona radiata (which links to the anterior cingulate cortex, an area where attention and emotion are thought to be integrated).

It’s an interesting question, the extent to which poor attentional control is a reflection of poor emotional regulation. Obviously there is more to distractability than that, but emotion and attention are clearly inextricably entwined. So, for example, a pilot study involving 10 middle school students with ADHD found that those who participated in twice-daily 10 minute sessions of Transcendental Meditation for three months showed a dramatic reduction in stress and anxiety and improvements in ADHD symptoms and executive function.

The effects of emotion regulation are of course wider than the effects on attention. Another domain they impact is that of decision-making. A study involving experienced Buddhist meditators found that they used different brain regions than controls when making decisions in a ‘fairness’ game. The differences reflected less input from emotional reactions and more emphasis on the actual benefits.

Similarly, brain scans taken while experienced and novice meditators meditated found that periodic bursts of disturbing noise had less effect on brain areas involved in emotion and decision-making for experienced meditators compared to novices — and very experienced meditators (at least 40,000 hours of experience) showed hardly any activity in these areas at all.

Attention is also entwined with perception, so it’s also interesting to observe that several studies have found improved visual perception attendant on meditation training and/or experience. Thus, participants attending a three-month meditation retreat, showed significant improvements in making fine visual distinctions, and ability to sustain attention.

But such benefits may depend on the style of meditation. A study involving experienced practitioners of two styles of meditation (Deity Yoga (DY) and Open Presence (OP)) found that DY meditators were dramatically better at mental rotation and visual memory tasks compared to OP practitioners and controls (and only if they were given the tasks immediately after meditating). Similarly, a study involving Tibetan Buddhist monks found that, during "one-point" meditation, monks were significantly better at maintaining their focus on one image, when two different images were presented to each eye. This superior attentional control was not found during compassion-oriented meditation. However, even under normal conditions the monks showed longer stable perception compared to meditation-naïve control subjects. And three months of intense training in Vipassana meditation produced an improvement in the ability of participants to detect the second of two visual signals half a second apart (the size of the improvement was linked to reduced brain activity to the first target — which was still detected with the same level of accuracy). Similarly, three months of intensive meditation training reduced variability in attentional processing of target tones.

References

You can read about these studies below in more detail. Three studies were mentioned here without having appeared in the news reports:

Lutz, A., Slagter, H. A., Rawlings, N. B., Francis, A. D., Greischar, L. L., & Davidson, R. J. (2009). Mental Training Enhances Attentional Stability: Neural and Behavioral Evidence. J. Neurosci., 29(42), 13418-13427. doi:10.1523/JNEUROSCI.1614-09.2009

Tang, Y.-Y., Lu, Q., Geng, X., Stein, E. A., Yang, Y., & Posner, M. I. (2010). Short-term meditation induces white matter changes in the anterior cingulate. Proceedings of the National Academy of Sciences, 107(35), 15649 -15652. doi:10.1073/pnas.1011043107

Travis, F., Haaga, D., Hagelin, J., Tanner, M., Arenander, A., Nidich, S., Gaylord-King, C., et al. (2010). A self-referential default brain state: patterns of coherence, power, and eLORETA sources during eyes-closed rest and Transcendental Meditation practice. Cognitive Processing, 11(1), 21-30. doi:10.1007/s10339-009-0343-2

Older news items (pre-2010) brought over from the old website

More on how meditation can improve attention

Another study adds to research showing meditation training helps people improve their ability to focus and ignore distraction. The new study shows that three months of rigorous training in Vipassana meditation improved people's ability to stabilize attention on target tones, when presented with tones in both ears and instructed to respond only to specific tones in one ear. Marked variability in response time is characteristic of those with ADHD.

[1500] Lutz, A., Slagter H. A., Rawlings N. B., Francis A. D., Greischar L. L., & Davidson R. J.
(2009).  Mental Training Enhances Attentional Stability: Neural and Behavioral Evidence.
J. Neurosci.. 29(42), 13418 - 13427.

http://www.physorg.com/news177347438.html

Meditation may increase gray matter

Adding to the increasing evidence for the cognitive benefits of meditation, a new imaging study of 22 experienced meditators and 22 controls has revealed that meditators showed significantly larger volumes of the right hippocampus and the right orbitofrontal cortex, and to a lesser extent the right thalamus and the left inferior temporal gyrus. There were no regions where controls had significantly more gray matter than meditators. These areas of the brain are all closely linked to emotion, and may explain meditators' improved ability in regulating their emotions.

[1055] Luders, E., Toga A. W., Lepore N., & Gaser C.
(2009).  The underlying anatomical correlates of long-term meditation: Larger hippocampal and frontal volumes of gray matter.
NeuroImage. 45(3), 672 - 678.

http://www.eurekalert.org/pub_releases/2009-05/uoc--htb051209.php

Meditation technique can temporarily improve visuospatial abilities

And continuing on the subject of visual short-term memory, a study involving experienced practitioners of two styles of meditation: Deity Yoga (DY) and Open Presence (OP) has found that, although meditators performed similarly to nonmeditators on two types of visuospatial tasks (mental rotation and visual memory), when they did the tasks immediately after meditating for 20 minutes (while the nonmeditators rested or did something else), practitioners of the DY style of meditation showed a dramatic improvement compared to OP practitioners and controls. In other words, although the claim that regular meditation practice can increase your short-term memory capacity was not confirmed, it does appear that some forms of meditation can temporarily (and dramatically) improve it. Since the form of meditation that had this effect was one that emphasizes visual imagery, it does support the idea that you can improve your imagery and visual memory skills (even if you do need to ‘warm up’ before the improvement is evident).

[860] Kozhevnikov, M., Louchakova O., Josipovic Z., & Motes M. A.
(2009).  The enhancement of visuospatial processing efficiency through Buddhist Deity meditation.
Psychological Science: A Journal of the American Psychological Society / APS. 20(5), 645 - 653.

http://www.sciencedaily.com/releases/2009/04/090427131315.htm
http://www.eurekalert.org/pub_releases/2009-04/afps-ssb042709.php

Transcendental Meditation reduces ADHD symptoms among students

A pilot study involving 10 middle school students with ADHD has found that those who participated in twice-daily 10 minute sessions of Trancendental Meditation for three months showed a dramatic reduction in stress and anxiety and improvements in ADHD symptoms and executive function. The effect was much greater than expected. ADHD children have a reduced ability to cope with stress.
A second, recently completed study has also found that three months practice of the technique resulted in significant positive changes in brain functioning during visual-motor skills, especially in the circuitry of the brain associated with attention and distractibility. After six months practice, measurements of distractibility moved into the normal range.

Grosswald, S. J., Stixrud, W. R., Travis, F., & Bateh, M. A. (2008, December). Use of the Transcendental Meditation technique to reduce symptoms of Attention Deficit Hyperactivity Disorder (ADHD) by reducing stress and anxiety: An exploratory study. Current Issues in Education [On-line], 10(2). Available: http://cie.ed.asu.edu/volume10/number2/

http://www.eurekalert.org/pub_releases/2008-12/muom-tmr122408.php

Meditation speeds the mind's return after distraction

Another study comparing brain activity in experienced meditators and novices has looked at what happens when people meditating were interrupted by stimuli designed to mimic the appearance of spontaneous thoughts. The study compared 12 people with more than three years of daily practice in Zen meditation with 12 others who had never practiced meditation. It was found that, after interruption, experienced meditators were able to bring activity in most regions of the default mode network (especially the angular gyrus, a region important for processing language) back to baseline faster than non-meditators. The default mode network is associated with the occurrence of spontaneous thoughts and mind-wandering during wakeful rest. The findings indicate not only the attentional benefits of meditation, but also suggest a value for disorders characterized by excessive rumination or an abnormal production of task-unrelated thoughts, such as obsessive-compulsive disorder, anxiety disorder and major depression.

[910] Pagnoni, G., Cekic M., & Guo Y.
(2008).  “Thinking about Not-Thinking”: Neural Correlates of Conceptual Processing during Zen Meditation.
PLoS ONE. 3(9), e3083 - e3083.

Full text available at http://dx.plos.org/10.1371/journal.pone.0003083
http://www.eurekalert.org/pub_releases/2008-09/eu-zts082908.php

Improved attention with mindfulness training

More evidence of the benefits of meditation for attention comes from a study looking at the performance of novices taking part in an eight-week course that included up to 30 minutes of daily meditation, and experienced meditators who attended an intensive full-time, one-month retreat. Initially, the experienced participants demonstrated better executive functioning skills, the cognitive ability to voluntarily focus, manage tasks and prioritize goals. After the eight-week training, the novices had improved their ability to quickly and accurately move and focus attention, while the experienced participants, after their one-month intensive retreat, also improved their ability to keep attention "at the ready."

[329] Jha, A. P., Krompinger J., & Baime M. J.
(2007).  Mindfulness training modifies subsystems of attention.
Cognitive, Affective & Behavioral Neuroscience. 7(2), 109 - 119.

http://www.eurekalert.org/pub_releases/2007-06/uop-mtc062507.php

Brain scans show how meditation affects the brain

An imaging study comparing novice and experienced meditators found that experienced meditators showed greater activity in brain circuits involved in paying attention. But the most experienced meditators with at least 40,000 hours of experience showed a brief increase in activity as they started meditating, and then a drop to baseline, as if they were able to concentrate in an effortless way. Moreover, while the subjects meditated inside the MRI, the researchers periodically blasted them with disturbing noises. Among the experienced meditators, the noise had less effect on the brain areas involved in emotion and decision-making than among novice meditators. Among meditators with more than 40,000 hours of lifetime practice, these areas were hardly affected at all. The attention circuits affected by meditation are also involved in attention deficit hyperactivity disorder.

[1364] Brefczynski-Lewis, J. A., Lutz A., Schaefer H. S., Levinson D. B., & Davidson R. J.
(2007).  Neural correlates of attentional expertise in long-term meditation practitioners.
Proceedings of the National Academy of Sciences. 104(27), 11483 - 11488.

Full text is available at http://tinyurl.com/3d6wx4
http://www.physorg.com/news102179695.html

Meditation may improve attentional control

Paying attention to one thing can keep you from noticing something else. When people are shown two visual signals half a second apart, they often miss the second one — this effect is called the attentional blink. In a study involving 40 participants being trained in Vipassana meditation (designed to reduce mental distraction and improve sensory awareness), one group of 17 attended a 3 month retreat during which they meditated for 10–12 hours a day (practitioner group), and 23 simply received a 1-hour meditation class and were asked to meditate for 20 minutes daily for 1 week prior to each testing session (control group). The three months of intense training resulted in a smaller attentional blink and reduced brain activity to the first target (which was still detected with the same level of accuracy. Individuals with the most reduction in activity generally showed the most reduction in attentional blink size. The study demonstrates that mental training can result in increased attentional control.

[1153] Slagter, H. A., Lutz A., Greischar L. L., Francis A. D., Nieuwenhuis S., Davis J. M., et al.
(2007).  Mental Training Affects Distribution of Limited Brain Resources.
PLoS Biol. 5(6), e138 - e138.

Full text available at http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050138 
http://www.physorg.com/news97825611.html
http://www.eurekalert.org/pub_releases/2007-05/uow-mmf050407.php

Meditation skills of Buddhist monks yield clues to brain's regulation of attention

Recent research has suggested that skilled meditation can alter certain aspects of the brain's neural activity. A new study has now found evidence that certain types of trained meditative practice can influence the conscious experience of visual perceptual rivalry, a phenomenon thought to involve brain mechanisms that regulate attention and conscious awareness. Perceptual rivalry arises normally when two different images are presented to each eye, and it is manifested as a fluctuation in the "dominant" image that is consciously perceived. The study involved 76 Tibetan Buddhist monks with training ranging from 5 to 54 years. Tested during the practice of two types of meditation: a "compassion"-oriented meditation (contemplation of suffering within the world), and "one-point" meditation (involving the maintained focus of attention on a single object or thought). Major increases in the durations of perceptual dominance were experienced by monks practicing one-point meditation, but not during compassion-oriented meditation. Additionally, under normal conditions the monks showed longer stable perception (average 4.1 seconds compared to 2.6 seconds for meditation-naïve control subjects). The findings suggest that processes particularly associated with one-point meditation can considerably alter the normal fluctuations in conscious state that are induced by perceptual rivalry.

[350] Carter, O., Presti D., Callistemon C., Ungerer Y., Liu G., & Pettigrew J.
(2005).  Meditation alters perceptual rivalry in Tibetan Buddhist monks.
Current Biology. 15(11), R412-R413 - R412-R413.

http://www.eurekalert.org/pub_releases/2005-06/cp-mso060205.php

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Religious factors may influence brain shrinkage in old age

July, 2011
  • An intriguing new study suggests life-changing religious experiences may result in greater brain shrinkage in old age.

The brain tends to shrink with age, with different regions being more affected than others. Atrophy of the hippocampus, so vital for memory and learning, is associated with increased risk of developing Alzheimer’s, and has also been linked to depression.

In a study involving 268 older adults (58+), the hippocampus of those reporting a life-changing religious experience was found to be shrinking significantly more compared to those not reporting such an experience. Significantly greater hippocampal atrophy was also found among born-again Protestants, Catholics, and those with no religious affiliation, compared with Protestants not identifying as born-again.

The participants are not a general sample — they were originally recruited for the NeuroCognitive Outcomes of Depression in the Elderly. However, some of the participants were from the control group, who had no history of depression. Brain scans were taken at the beginning of the study, and then every two years. The length of time between the baseline scan and the final scan ranged from 2 to 8 years (average was 4).

Questions about religious experiences were asked in an annual survey, so could change over time. Two-thirds of the group was female, and 87% were white. The average age was 68. At baseline, 42% of the group was non-born-again Protestant, 36% born-again Protestant; 8% Catholic; 6% other religion. Only 7% reported themselves as having no religion. By the end of the study, 44% (119 participants) reported themselves born-again, and 13% (36) reported having had life-changing religious experiences.

These associations persisted after depression status, acute stress, and social support were taken into account. Nor did other religious factors (such as prayer, meditation, or Bible study) account for the changes.

It is still possible that long-term stress might play a part in this association — the study measured acute rather than cumulative stress. The researchers suggest that life-changing religious experiences can be stressful, if they don’t fit in with your existing beliefs or those of your family and friends, or if they lead to new social systems that add to your stress.

Of course, the present results can be interpreted in several ways — is it the life-changing religious experience itself that is the crucial factor? Or the factors leading up to that experience? Or the consequences of that experience? Still, it’s certainly an intriguing finding, and it will be interesting to see more research expanding and confirming (or not!) this result.

More generally, the findings may help clarify the conflicting research about the effects of religion on well-being, by pointing to the fact that religion can’t be considered a single factor, but one subject to different variables, some of which may be positive and others not.

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Some cancer survivors can't shake foggy brain

July, 2011

For a minority of cancer survivors, cognitive problems will persist for years. Help with sleeping problems, and t’ai chi for stress release, may be beneficial.

A recent study of cancer survivors has found that many survivors still suffer moderate to severe problems with pain, fatigue, sleep, memory and concentration three to five years after treatment has ended.

The study included 248 survivors of breast, colorectal, lung and prostate cancer. The survivors were primarily female and white, and most were more than five years post-diagnosis. Cognitive difficulties were reported by 13%. The other most common symptoms were fatigue (16%), disturbed sleep (15%), and pain (13%). Two assessments were made, one month apart. The similar results indicate these symptoms tend to be chronic.

The researchers pointed to the need for education programs to help survivors transition from treatment to life as a cancer survivor, and the need for clinicians and researchers to develop better ways to address sleep problems, fatigue and lasting difficulties with memory and concentration.

One activity that could be part of a post-treatment program is t'ai chi.  A recent pilot study involving 23 women with a history of chemotherapy has found better cognitive and physical functioning after 10 weeks participating in a 60-minute t’ai chi class twice a week. Before and after the intervention, participants completed tests of memory, executive functioning, language, and attention, as well as tests of balance and self-report questionnaires of neuropsychological complaints, stress and mood, and fatigue.

However, though I’m a big fan of t’ai chi, I do have to note that without a control group, allowing the passing of time and the effects of any sort of group activity to be taken into account, it’s hard to draw any real conclusions from this.

Still, some support for this finding can be found in a recent meta-analysis of research investigating the benefits of t'ai chi for any improvement of medical conditions or clinical symptoms. This review found that the only clear evidence is in relation to fall prevention and improving psychological health. So, only middling support for t'ai chi, but the affirmation of its benefit for psychological health does support the potential value of this meditational practice for cancer survivors.

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The findings of the first study were presented June 4 at the 2011 American Society of Clinical Oncology Annual Meeting in Chicago.

[2320] Reid-Arndt, S. A., Matsuda S., & Cox C. R.
(Submitted).  Tai Chi effects on neuropsychological, emotional, and physical functioning following cancer treatment: A pilot study.
Complementary Therapies in Clinical Practice. In Press, Corrected Proof,

[2319] Lee, M S., & Ernst E.
(2011).  Systematic reviews of t'ai chi: an overview.
British Journal of Sports Medicine.

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Mindfulness meditation may help attention through better control of alpha rhythms

May, 2011

New research suggests that meditation can improve your ability to control alpha brainwaves, thus helping you block out distraction.

As I’ve discussed on many occasions, a critical part of attention (and working memory capacity) is being able to ignore distraction. There has been growing evidence that mindfulness meditation training helps develop attentional control. Now a new study helps fill out the picture of why it might do so.

The alpha rhythm is particularly active in neurons that process sensory information. When you expect a touch, sight or sound, the focusing of attention toward the expected stimulus induces a lower alpha wave height in neurons that would handle the expected sensation, making them more receptive to that information. At the same time the height of the alpha wave in neurons that would handle irrelevant or distracting information increases, making those cells less receptive to that information. In other words, alpha rhythm helps screen out distractions.

In this study, six participants who completed an eight-week mindfulness meditation program (MBSR) were found to generate larger alpha waves, and generate them faster, than the six in the control group. Alpha wave activity in the somatosensory cortex was measured while participants directed their attention to either their left hand or foot. This was done on three occasions: before training, at three weeks of the program, and after the program.

The MBSR program involves an initial two-and-a-half-hour training session, followed by daily 45-minute meditation sessions guided by a CD recording. The program is focused on training participants first to pay close attention to body sensations, then to focus on body sensations in a specific area, then being able to disengage and shifting the focus to another body area.

Apart from helping us understand why mindfulness meditation training seems to improve attention, the findings may also explain why this meditation can help sufferers of chronic pain.

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