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

Mindfulness meditation is associated with various positive benefits, one of which is improved attention, but it might not be all good. A new study suggests that it may have negative cognitive consequences.

The study included three experiments, in the first two of which undergraduates carried out a 15-minute guided exercise: one group was instructed to focus attention on their breathing without judgment (mindfulness group); the other group was told to think about whatever came to mind (mind-wandering group; the control).

In the first experiment, 153 participants then studied a list of 15 words related to the concept of trash, but not including the word "trash". When then asked to recall as many of the words from the list as they could remember, 39% of the mindfulness group falsely recalled seeing the word "trash" on the list compared to only 20% of the mind-wandering group. There was no difference between the groups in the number of other words falsely recalled.

In the second experiment, 140 participants were compared to themselves, before and after the intervention. They all began by doing six of the same sort of word lists. They were then randomly assigned either the meditation exercise or the mind-wandering. This was then followed by a further six word lists.

Again, mindfulness participants were more likely to falsely recall the critical word than those who engaged in mind wandering. Those in the mind-wandering group showed no difference in performance on the word lists before and after, while those in the meditation group were significantly more likely to falsely remember the critical item. Again, there were no other differences in performance between the groups: they correctly recalled about the same number of words, and they falsely remembered about the same number of other words.

In the third experiment, 215 undergraduates had to determine whether a word had been presented earlier, where the words shown were all part of a strongly associated pair (e.g., foot-shoe). After seeing the 100 words (for 1.5 seconds each), they were then tested. Each word had an equal chance of being one of the words in the presented list, or its associated pair. All students were then given the 15-minute meditation exercise, before going through the process again.

Again, the rate of words correctly identified as seen before was about the same before and after the meditation exercise, but the rate of words falsely identified increased significantly after the exercise.

In all, then, it seems that mindfulness meditation increased participants' susceptibility to false memories, reducing their ability to differentiate items they actually encountered from items they only imagined (because of their strong association to the items encountered).

The researchers speculate that the mechanism that seems to underlie the benefits of mindfulness — judgment-free thoughts and feelings — might also affect people's ability to determine the origin of a given memory (source memory), because they have become less able to distinguish between externally occurring events and internally generated events.

Source memory is one of those memory domains that tend to be affected by aging. However, the benefits of meditation for improving attention — another area particularly affected by age — outweigh this downside. So I'm certainly not suggesting anyone should be put off by this finding!

An interesting question that remains to be answered is whether this negative effect on source memory is short-lived, or whether experienced meditators tend to have poorer source memory.

http://www.eurekalert.org/pub_releases/2015-09/afps-mmm090915.php

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

[3921] McNab F, Zeidman P, Rutledge RB, Smittenaar P, Brown HR, Adams RA, Dolan RJ. Age-related changes in working memory and the ability to ignore distraction. Proceedings of the National Academy of Sciences [Internet]. 2015 ;112(20):6515 - 6518. Available from: http://www.pnas.org/content/112/20/6515

McNab, F., & Dolan, R. J. (2014). Dissociating distractor-filtering at encoding and during maintenance. Journal of Experimental Psychology. Human Perception and Performance, 40(3), 960–7. doi:10.1037/a0036013

A review of meditation research reported in January last year concluded that there were insufficient good studies to allow us to say that meditation clearly improves attention and cognition. Studies from 2014 suggest three factors that might be part of the reason for inconsistent research findings:

  • the age of the subjects (with benefits being more evident in older participants)
  • the cognitive tests used (some may be insufficiently demanding to reveal effects, especially in younger adults)
  • the type of meditation (meditative practices that increase arousal may be more beneficial than those that encourage relaxation).

Of course, there are other potentially significant factors as well, such as the meditation experience of the participants. What we really need is a more methodical research program. Nevertheless, the results are promising.

Review of meditation research

At the beginning of last year, a very large review of the meditation research by the US Agency for Healthcare Research and Quality (AHRQ) came out, and concluded that while meditation, and mindfulness meditation in particular, helps reduce stress and some other negative factors, the quality and quantity of studies to date means that we should be cautious of drawing too many conclusions as regards type of meditation, the groups of people who might benefit, and specific benefits.

So, for example, while MBSR appears to help with musculoskeletal pain, almost no other types of pain have been studied, and we cannot therefore conclude that any other types of pain will be alleviated.

The study reviewed 47 clinical trials from 2012 that evaluated the effects of meditation on individuals with diagnosed health problems. These represent a mere 3% of the meditation studies published that year, being those that met the stringent criteria:

  • subjects randomly assigned to a mediation or control group
  • control condition to require a similar amount of time and focus as meditation
  • whether the researchers knew what intervention they had received

They found moderate evidence that mindfulness meditation alleviates pain, anxiety and depression (the latter two to a similar degree as antidepressant drug therapy), but found low evidence of no effect or insufficient evidence of any effect of meditation programs on mood or attention. Nor could they find sufficient evidence for the benefits of other types of meditation. They also found no evidence that meditation programs were better than any active treatment (drugs, exercise, or other behavioral therapies).

The researchers made it clear that the problem lies in a paucity of good studies, and hoped that their findings would encourage better quality research.

http://www.patheos.com/blogs/americanbuddhist/2014/01/the-effectiveness-of-meditation-a-meta-analysi.html

http://effectivehealthcare.ahrq.gov/ehc/products/375/1830/Meditation-report-140106.pdf

http://www.scientificamerican.com/article/is-meditation-overrated/

Here are some of the 2014 studies suggesting cognitive benefits. These suggest several reasons why research findings may have been inconsistent.

Meditation slows age-related loss of gray matter

Following an earlier study that suggested people who meditate have less age-related atrophy in their white matter, a new study has found that meditation also appears to help preserve gray matter.

The study compared 50 experienced mediatators against 50 age- and gender-matched controls. Each group contained 28 men and 22 women ranging in age from 24 to 77. Those who meditated had been doing so for four to 46 years, with an average of 20 years.

While both groups showed a loss of gray matter as they aged, the decline was significantly less in those who meditated. Moreover, the loss of gray matter was more widespread among those who didn't meditate, including several regions previously implicated in meditation effects.

Interestingly, a 2007 study found a smaller difference between their controls and meditators, as well as a more localized effect (only one region, the putamen, showed a significant difference in gray matter, compared to this study's finding of nine significant clusters across the brain). It's plausibly suggested that the difference may lie in the average age of the subjects: the average age in the earlier study was in the mid-thirties, while the average in this recent study was in the early-fifties.

In other words, the benefits of meditation for cognition may be better seen as we get older.

http://www.eurekalert.org/pub_releases/2015-02/uoc--fym020515.php

Yoga and meditation produce better brainwaves

Another, related, reason for meditation to produce inconsistent or small cognitive benefits is that the cognitive testing is insufficiently demanding. A recent study has found that those who practiced yoga and meditation long term learned to control a computer with their minds faster and better than people with little or no yoga or meditation experience.

The study involved 36 participants, of whom 12 had at least one year of experience in yoga or meditation at least twice a week for one hour. Participants were given three, two-hour training sessions with a human-computer interface, in which they had to try to move a computer cursor across the screen by visualizing left or right hand movements.

The participants with yoga or meditation experience were twice as likely to complete the brain-computer interface task by the end of 30 trials and learned three times faster than their counterparts for the left-right cursor movement experiments.

There has been much in the news in recent years about these interfaces, which allow a person to control a computer or robot with their minds, and offer such promise for people who are paralyzed. However, it turns out that not everyone can easily learn to use the interface, and it's been speculated that the problem may lie in the clarity and steadiness of the brain signal. Meditators have shown more distinctive EEG patterns than untrained participants, which may explain their success.

http://www.eurekalert.org/pub_releases/2014-09/uom-nss092514.php

Hatha yoga boosts brain function in older adults

Yoga has also been shown to help executive function in older adults.

A study involving 108 sedentary older adults (55-79), of whom 61 attended hatha yoga classes three times a week for eight weeks, found that the yoga practice improved their cognitive performance, compared to those who spent the same time engaged in stretching and toning exercises.

At the end of the eight weeks, the yoga group was faster and more accurate on task switching and working memory capacity tests. There was no change in performance for those in the stretching group.

http://www.eurekalert.org/pub_releases/2014-08/uoia-ssh081814.php

Some meditation practices are better than others

A third reason for inconsistency may come from the fact that meditation comes in many flavors. Are they all equally helpful? Two studies in 2014 gave us some pointers.

The first study distinguished two main types of meditation technique:

  • concentrative meditation, where the meditator focuses attention on their breathing or on specific thoughts, thus suppressing other thoughts
  • nondirective meditation, where the meditator focuses on their breathing or a meditation sound, but allows the mind to wander freely.

In this study, 14 meditators skilled in a nondirective technique called Acem meditation had their brains scanned while resting or performing nondirective meditation or a more concentrative meditation task. Surprisingly, nondirective meditation led to higher activity in the right medial temporal lobe (parahippocampal gyrus and amygdala) — areas associated with attention, mind wandering, retrieval of episodic memories, and emotional processing — while the level of brain activity in this region when the meditators performed concentrative meditation was about the same as during rest.

The results suggest that nondirective meditation produces more extensive activation of the default mode network. This finding contrasts with other studies that have indicated meditation reduces activity in the default mode network.

Which should we believe? Well, the second study compared four different types of meditative practices (two types of Vajrayana meditation practices (visualization of self-generation-as-Deity and Rig-pa) and two types of Theravada practices (Shamatha and Vipassana)). This distinction cuts across the previous distinction. Shamatha (Theravada) and self-generation-as-Deity (Varjrayana) are examples of focused attention / concentrative meditation. Vipassana (Theravada) and Rig-pa (Vajrayana) have been classified as non-focused / nondirective. These researchers argue that this broad distinction is not a particularly accurate or helpful one, pointing to the inconsistent findings regarding whether focused and non-focused meditation show clearly distinct neurophysiological substrates. Their findings support this view (although of course it's easy to be consistent with one study! more research is clearly needed).

The study found that physiological responses during the Theravada meditation differed significantly from those during the Vajrayana meditation, with Theravada meditation producing enhanced parasympathetic activation (relaxation), while Vajrayana meditation didn't show any evidence of parasympathetic activity but showed an activation of the sympathetic system (arousal).

Arousal is more likely to be associated with attention, and indeed, cognitive performance improved (immediately and dramatically) only following the Vajrayana styles of meditation. This was shown in a mental rotation test and a visual memory test.

In other words, to deal with stress and become more relaxed, you should choose a Theravada meditation, but if your desire is to improve your powers of concentration, you should practice a Vajrayana meditation. Note however, that this study looked only at the immediate alertness following meditation — whether experienced Vajrayana meditators are at an advantage in general is a separate issue.

It's worth noting that most meditation studies have investigated Theravada meditative practices.

The study involved 12 experienced Theravada meditators (average 10 years experience) from a Thai temple, 14 experienced Theravada meditators (average 12.3 years experience) from a Nepalese Buddhist Meditation Center, and 9 experienced Vajrayana meditators (average 7.4 years experience) from a Nepalese monastery.

http://www.eurekalert.org/pub_releases/2014-05/nuos-tiy051514.php

http://www.futurity.org/buddhist-meditation-brains-768872/

[3888] Goyal M, S S, ES S, et al. Meditation programs for psychological stress and well-being: A systematic review and meta-analysis. JAMA Internal Medicine [Internet]. 2014 ;174(3):357 - 368. Available from: http://dx.doi.org/10.1001/jamainternmed.2013.13018

[3887] Luders E, Cherbuin N, Kurth F. Forever Young(er): potential age-defying effects of long-term meditation on gray matter atrophy. Cognition [Internet]. 2015 ;5. Available from: http://journal.frontiersin.org/Journal/10.3389/fpsyg.2014.01551/full

[3885] Cassady K, You A, Doud A, He B. The impact of mind-body awareness training on the early learning of a brain-computer interface. TECHNOLOGY [Internet]. 2014 ;02(03):254 - 260. Available from: http://www.worldscientific.com/doi/abs/10.1142/S233954781450023X

[3886] Gothe NP, Kramer AF, McAuley E. The Effects of an 8-Week Hatha Yoga Intervention on Executive Function in Older Adults. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences [Internet]. 2014 . Available from: http://biomedgerontology.oxfordjournals.org/content/early/2014/07/14/gerona.glu095

[3889] Xu J, Vik A, Groote IRasmus, Lagopoulos J, Holen A, Ellingsen Ø, Davanger S. Nondirective meditation activates default mode network and areas associated with memory retrieval and emotional processing. Frontiers in Human Neuroscience [Internet]. 2014 ;8. Available from: http://journal.frontiersin.org/Journal/10.3389/fnhum.2014.00086/abstract

[3884] Amihai I, Kozhevnikov M. Arousal vs. Relaxation: A Comparison of the Neurophysiological and Cognitive Correlates of Vajrayana and Theravada Meditative Practices. PLoS ONE [Internet]. 2014 ;9(7). Available from: http://dx.doi.org/10.1371/journal.pone.0102990

 

Three classroom experiments have found that students who meditated before a psychology lecture scored better on a quiz that followed than students who did not meditate. Mood, relaxation, and class interest were not affected by the meditation training.

The noteworthy thing is that the meditation was very very basic — six minutes of written meditation exercises.

The effect was stronger in classes where more freshmen students were enrolled, suggesting that the greatest benefit is to those students who have most difficulty in concentrating (who are more likely to drop out).

The finding suggests the value in teaching some active self-reflection strategies to freshmen, and disadvantaged ones in particular.

It’s reasonable to speculate that more extensive training might increase the benefits.

And in another recent meditation study, a two week mindfulness course significantly improved both Graduate Record Exam reading comprehension scores and working memory capacity.

The study involved 48 undergrads who either attended the mindfulness course or a nutrition class. Each 45-minute class met eight times over two weeks. Mindfulness training was associated with a 16-percentile boost in GRE scores, on average. Mind wandering also significantly decreased. The healthy nutrition course had no effect on any of these factors.

http://medicalxpress.com/news/2013-04-meditating-grades.html (first study)

[3382] Ramsburg JT, Youmans RJ. Meditation in the Higher-Education Classroom: Meditation Training Improves Student Knowledge Retention during Lectures. Mindfulness [Internet]. Submitted :1 - 11. Available from: http://link.springer.com/article/10.1007/s12671-013-0199-5

http://www.scientificamerican.com/podcast/episode.cfm?id=mindfulness-may-improve-test-scores-13-03-28 (second study)

[3380] Mrazek MD, Franklin MS, Phillips DT, Baird B, Schooler JW. Mindfulness Training Improves Working Memory Capacity and GRE Performance While Reducing Mind Wandering. Psychological Science [Internet]. 2013 . Available from: http://pss.sagepub.com/content/early/2013/03/27/0956797612459659

Why do we find it so hard to stay on task for long? A recent study uses a new technique to show how the task control network and the default mode network interact (and fight each other for control).

The task control network (which includes the dorsal anterior cingulate and bilateral anterior insula) regulates attention to surroundings, controlling your concentration on tasks. The default mode network, on the other hand, becomes active when a person seems to be doing 'nothing', and becomes less active when a task is being performed.

The study shows that we work better and faster the better the default mode network is suppressed by the task control network. However, when the default mode network is not sufficiently suppressed by the task control network, it sends signals to the task control network, interfering with its performance (and we lose focus).

Interestingly, in certain conditions, such as autism, depression, and mild cognitive impairment, the default mode network remains unchanged whether the person is performing a task or interacting with the environment. Additionally, deficits in the functioning of the default mode network have been implicated in age-related cognitive decline.

The findings add a new perspective to our ideas about attention. One of the ongoing questions concerns the relative importance of the two main aspects of attention: focus, and resisting distraction. A lot of work in recent years has indicated that a large part of age-related cognitive decline is a growing difficulty in resisting distraction. Similarly, there is some evidence that people with a low working memory capacity are less able to ignore irrelevant information.

This recent finding, then, suggests that these difficulties in ignoring distracting / irrelevant stimuli reflect the failure of the task control network to adequately suppress the activity of the default mode network. This puts the emphasis back on training for focus, and may help explain why meditation practices are effective in improving concentration.

http://www.futurity.org/science-technology/why-your-seesaw-brain-cant-stay-on-task/

[3384] Wen X, Liu Y, Yao L, Ding M. Top-Down Regulation of Default Mode Activity in Spatial Visual Attention. The Journal of Neuroscience [Internet]. 2013 ;33(15):6444 - 6453. Available from: http://www.jneurosci.org/content/33/15/6444

Here’s an encouraging study for all those who think that, because of age or physical damage, they must resign themselves to whatever cognitive impairment or decline they have suffered. In this study, older adults who had suffered from aphasia for a long time nevertheless improved their language function after six weeks of intensive training.

The study involved nine seniors with chronic aphasia and 10 age-matched controls. Those with aphasia were given six weeks of intensive and specific language therapy, after which they showed significantly better performance at naming objects. Brain scans revealed that the training had not only stimulated language circuits, but also integrated the default mode network (the circuits used when our brain is in its ‘resting state’ — i.e., not thinking about anything in particular), producing brain activity that was similar to that of the healthy controls.

Moreover, these new circuits continued to be active after training, with participants continuing to improve.

Previous research has implicated abnormal functioning of the default mode network in other cognitive disorders.

Although it didn’t reach significance, there was a trend suggesting that the level of integration of the default mode network prior to therapy predicted the outcome of the training.

The findings are especially relevant to the many seniors who no longer receive treatment for stroke damage they may have had for many years. They also add to the growing evidence for the importance of the default mode network. Changes in the integration of the default mode network with other circuits have also been implicated in age-related cognitive decline and Alzheimer’s.

Interestingly, some research suggests that meditation may help improve the coherence of brainwaves that overlap the default mode network. Meditation, already shown to be helpful for improving concentration and focus, may be of greater benefit for fighting age-related cognitive decline than we realize!

More evidence that even an 8-week meditation training program can have measurable effects on the brain comes from an imaging study. Moreover, the type of meditation makes a difference to how the brain changes.

The study involved 36 participants from three different 8-week courses: mindful meditation, compassion meditation, and health education (control group). The courses involved only two hours class time each week, with meditation students encouraged to meditate for an average 20 minutes a day outside class. There was a great deal of individual variability in the total amount of meditation done by the end of the course (210-1491 minutes for the mindful attention training course; 190-905 minutes for the compassion training course).

Participants’ brains were scanned three weeks before the courses began, and three weeks after the end. During each brain scan, the volunteers viewed 108 images of people in situations that were either emotionally positive, negative or neutral.

In the mindful attention group, the second brain scan showed a decrease in activation in the right amygdala in response to all images, supporting the idea that meditation can improve emotional stability and response to stress. In the compassion meditation group, right amygdala activity also decreased in response to positive or neutral images, but, among those who reported practicing compassion meditation most frequently, right amygdala activity tended to increase in response to negative images. No significant changes were seen in the control group or in the left amygdala of any participant.

The findings support the idea that meditation can be effective in improving emotional control, and that compassion meditation can indeed increase compassionate feelings. Increased amygdala activation was also correlated with decreased depression scores in the compassion meditation group, which suggests that having more compassion towards others may also be beneficial for oneself.

The findings also support the idea that the changes brought about by meditation endure beyond the meditative state, and that the changes can start to occur quite quickly.

These findings are all consistent with other recent research.

One point is worth emphasizing, in the light of the difficulty in developing a training program that improves working memory rather than simply improving the task being practiced. These findings suggest that, unlike most cognitive training programs, meditation training might produce learning that is process-specific rather than stimulus- or task-specific, giving it perhaps a wider generality than most cognitive training.

Meditation may improve multitasking

I recently reported that developing skill at video action games doesn’t seem to improve general multitasking ability, but perhaps another approach might be more successful. Meditation has, of course, been garnering growing evidence that it can help improve attentional control. A new study extends that research to multitasking in a realistic work setting.

The study involved three groups of 12-15 female human resource managers, of whom one group received eight weeks of mindfulness-based meditation training, another received eight weeks of body relaxation training, and another initially received no training (control), before receiving the mindfulness training after the eight weeks.

Before and after each eight-week period, the participants were given a stressful test of their multitasking abilities, requiring them to use email, calendars, instant-messaging, telephone and word-processing tools to perform common office tasks (scheduling a meeting; finding a free conference room; writing a draft announcement of the meeting, eating snacks and drinking water, writing a memo proposing a creative agenda item for the meeting). Necessary information came from emails, instant messages, telephone calls, and knocks on the door. The participants had 20 minutes to complete the tasks.

The meditation group reported lower levels of stress during the multitasking test compared to the control and relaxation groups. They also spent more time on tasks and switched tasks less often, while taking no longer to complete the overall job than the others. Both meditation and relaxation groups showed improved memory for the tasks they were performing.

After the control group underwent the meditation training, their results matched those of the meditation group.

The meditation training emphasized:

  • control of attentional focus
  • focusing attention in the present moment or task
  • switching focus
  • breath and body awareness.

The relaxation training emphasized progressive tensing and relaxing of major muscle groups, aided by relaxation imagery.

It's interesting that overall time on task didn't change (the researchers remarked that the meditators didn't take any longer, but of course most of us would be looking for it to become shorter!), but I wouldn't read too much into it. The task was relatively brief. It would be interesting to see the effects over the course of, say, a day. Nor did the study look at how well the tasks were done.

But it is, of course, important that meditation training reduced task-switching and stress. Whether it also has a postitive effect on overall time and quality of work is a question for another day.

IBMT improves white matter efficiency

A recent imaging study has found that four weeks of a form of mindfulness meditation called integrative body–mind training (IBMT) improved white matter efficiency in areas surrounding the anterior cingulate cortex, compared to controls given relaxation training.

The anterior cingulate is part of the brain network related to self-regulation. Deficits in activation in this part of the brain have been associated with attention deficit disorder, dementia, depression, schizophrenia, and other disorders.

Using the data from a 2010 study involving 45 U.S. college students, and another involving 68 Chinese students, researchers found that axon density (one factor in white matter efficiency) had improved after two weeks, but not myelin formation. After a month (about 11 hours of meditation), both had improved. Mood improved by two weeks.

Previous studies involving computer-based training for improving working memory have found changes in myelination, but not axon density.

Meditators’ better cognitive control may be rooted in emotional regulation

Previous work has found that people who engage in meditation show higher levels of executive control on laboratory tasks.

An electrical signal called the Error Related Negativity (ERN) occurs in the brain within 100 ms of an error being committed. When meditators and non-meditators were given the Stroop Test, meditators not only tended to do better on the test, but their ERNs were stronger.

The interesting thing about this is that the best performers were those who scored highest on emotional acceptance. Mindful awareness was less important. It’s suggested that meditators may be able to control their behavior better not because of their sharper focus, but because they are more aware of their emotions and regulate them better.

Something to think about!

Levy, D. M., Wobbrock, J. O., Kaszniak, A. W., & Ostergren, M. (2012). The Effects of Mindfulness Meditation Training on Multitasking in a High-Stress Information Environment, 45–52. Full text available at http://faculty.washington.edu/wobbrock/pubs/gi-12.02.pdf

[3051] Tang Y-Y, Lu Q, Fan M, Yang Y, Posner MI. Mechanisms of white matter changes induced by meditation. Proceedings of the National Academy of Sciences [Internet]. 2012 ;109(26):10570 - 10574. Available from: http://www.pnas.org/content/109/26/10570

[3052] Teper R, Inzlicht M. Meditation, mindfulness and executive control: the importance of emotional acceptance and brain-based performance monitoring. Social Cognitive and Affective Neuroscience [Internet]. 2012 . Available from: http://scan.oxfordjournals.org/content/early/2012/05/13/scan.nss045

I’ve always felt that better thinking was associated with my brain working ‘in a higher gear’ — literally working at a faster rhythm. So I was particularly intrigued by the findings of a recent mouse study that found that brainwaves associated with learning became stronger as the mice ran faster.

In the study, 12 male mice were implanted with microelectrodes that monitored gamma waves in the hippocampus, then trained to run back and forth on a linear track for a food reward. Gamma waves are thought to help synchronize neural activity in various cognitive functions, including attention, learning, temporal binding, and awareness.

We know that the hippocampus has specialized ‘place cells’ that record where we are and help us navigate. But to navigate the world, to create a map of where things are, we need to also know how fast we are moving. Having the same cells encode both speed and position could be problematic, so researchers set out to find how speed was being encoded. To their surprise and excitement, they found that the strength of the gamma rhythm grew substantially as the mice ran faster.

The results also confirmed recent claims that the gamma rhythm, which oscillates between 30 and 120 times a second, can be divided into slow and fast signals (20-45 Hz vs 45-120 Hz for mice, consistent with the 30-55 Hz vs 45-120 Hz bands found in rats) that originate from separate parts of the brain. The slow gamma waves in the CA1 region of the hippocampus were synchronized with slow gamma waves in CA3, while the fast gamma in CA1 were synchronized with fast gamma waves in the entorhinal cortex.

The two signals became increasingly separated with increasing speed, because the two bands were differentially affected by speed. While the slow waves increased linearly, the fast waves increased logarithmically. This differential effect could have to do with mechanisms in the source regions (CA3 and the medial entorhinal cortex, respectively), or to mechanisms in the different regions in CA1 where the inputs terminate (the waves coming from CA3 and the entorhinal cortex enter CA1 in different places).

In the hippocampus, gamma waves are known to interact with theta waves. Further analysis of the data revealed that the effects of speed on gamma rhythm only occurred within a narrow range of theta phases — but this ‘preferred’ theta phase also changed with running speed, more so for the slow gamma waves than the fast gamma waves (which is not inconsistent with the fact that slow gamma waves are more affected by running speed than fast gamma waves). Thus, while slow and fast gamma rhythms preferred similar phases of theta at low speeds, the two rhythms became increasingly phase-separated with increasing running speed.

What’s all this mean? Previous research has shown that if inputs from CA3 and the entorhinal cortex enter CA1 at the same time, the kind of long-term changes at the synapses that bring about learning are stronger and more likely in CA1. So at low speeds, synchronous inputs from CA3 and the entorhinal cortex at similar theta phases make them more effective at activating CA1 and inducing learning. But the faster you move, the more quickly you need to process information. The stronger gamma waves may help you do that. Moreover, the theta phase separation of slow and fast gamma that increases with running speed means that activity in CA3 (slow gamma source) increasingly anticipates activity in the medial entorhinal cortex (fast gamma source).

What does this mean at the practical level? Well at this point it can only be speculation that moving / exercising can affect learning and attention, but I personally am taking this on board. Most of us think better when we walk. This suggests that if you’re having trouble focusing and don’t have time for that, maybe walking down the hall or even jogging on the spot will help bring your brain cells into order!

Pushing speculation even further, I note that meditation by expert meditators has been associated with changes in gamma and theta rhythms. And in an intriguing comparison of the effect of spoken versus sung presentation on learning and remembering word lists, the group that sang showed greater coherence in both gamma and theta rhythms (in the frontal lobes, admittedly, but they weren’t looking elsewhere).

So, while we’re a long way from pinning any of this down, it may be that all of these — movement, meditation, music — can be useful in synchronizing your brain rhythms in a way that helps attention and learning. This exciting discovery will hopefully be the start of an exploration of these possibilities.

Following on from research showing that long-term meditation is associated with gray matter increases across the brain, an imaging study involving 27 long-term meditators (average age 52) and 27 controls (matched by age and sex) has revealed pronounced differences in white-matter connectivity between their brains.

The differences reflect white-matter tracts in the meditators’ brains being more numerous, more dense, more myelinated, or more coherent in orientation (unfortunately the technology does not yet allow us to disentangle these) — thus, better able to quickly relay electrical signals.

While the differences were evident among major pathways throughout the brain, the greatest differences were seen within the temporal part of the superior longitudinal fasciculus (bundles of neurons connecting the front and the back of the cerebrum) in the left hemisphere; the corticospinal tract (a collection of axons that travel between the cerebral cortex of the brain and the spinal cord), and the uncinate fasciculus (connecting parts of the limbic system, such as the hippocampus and amygdala, with the frontal cortex) in both hemispheres.

These findings are consistent with the regions in which gray matter increases have been found. For example, the tSLF connects with the caudal area of the temporal lobe, the inferior temporal gyrus, and the superior temporal gyrus; the UNC connects the orbitofrontal cortex with the amygdala and hippocampal gyrus

It’s possible, of course, that those who are drawn to meditation, or who are likely to engage in it long term, have fundamentally different brains from other people. However, it is more likely (and more consistent with research showing the short-term effects of meditation) that the practice of meditation changes the brain.

The precise mechanism whereby meditation might have these effects can only be speculated. However, more broadly, we can say that meditation might induce physical changes in the brain, or it might be protecting against age-related reduction. Most likely of all, perhaps, both processes might be going on, perhaps in different regions or networks.

Regardless of the mechanism, the evidence that meditation has cognitive benefits is steadily accumulating.

The number of years the meditators had practiced ranged from 5 to 46. They reported a number of different meditation styles, including Shamatha, Vipassana and Zazen.

The study involved 26 experienced Buddhist meditators and 40 control subjects. Scans of their brains while they played the "ultimatum game," in which the first player proposes how to divide a sum of money and the second can accept or reject the proposal, revealed that the two groups engaged different parts of the brain when making these decisions.

Consistent with earlier studies, controls showed increased activity in the anterior insula (involved in disgust and emotional reactions to unfairness and betrayal) when the offers were unfair. However the Buddhist meditators showed higher activity instead in the posterior insula (involved in interoception and attention to the present moment). In other words, rather than dwelling on emotional reactions and imaginary what-if scenarios, the meditators concentrated on the interoceptive qualities that accompany any reward, no matter how small.

The meditators accepted unfair offers on more than half of the trials, whereas controls only accepted unfair offers on a quarter of the trials.

Moreover, those controls who did in fact play the game ‘rationally’ (that is, mostly accepting the unfair offers) showed activity in the dorsolateral prefrontal cortex, while rational meditators displayed increased activity in the somatosensory cortex and posterior superior temporal cortex.

The most intriguing thing about all this is not so much that regular meditation might change the way your brain works (although that is undeniably interesting), but as a more general demonstration that we can train our brain to work in different ways. Something to add to the research showing how brain regions shift in function in those with physical damage to their brains or sense organs (eg, in those who become blind).

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.

Brain images of 16 participants in an 8-week mindfulness meditation program, taken two weeks before and after the program, have found measurable changes in brain regions associated with memory, sense of self, empathy and stress. Specifically, they 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. Similar brain scans of a control group of non-meditators (those on a waiting list for the program) showed no such changes over time.

Although a number of studies have found differences in the brains of experienced meditators and those who don’t practice meditation, this is the first to demonstrate that those differences are actually produced by meditation.

The Mindfulness-Based Stress Reduction program involved weekly meetings that included practice of mindfulness meditation and audio recordings for guided meditation practice. Participants reported spending an average of 27 minutes each day practicing mindfulness exercises.

Mindfulness Training had a positive effect on both working memory capacity and mood in a group of Marine reservists during the high-stress pre-deployment interval. While those who weren’t given the 8-week MT program, as well as those who spent little time engaging in mindfulness exercises, showed greater negative mood and decreased working memory capacity over the eight weeks, those who recorded high practice time showed increased capacity and decreased negative mood. A civilian control group showed no change in working memory capacity over the period. The program, called Mindfulness-based Mind Fitness Training (MMFT™), blended mindfulness skills training with concrete applications for the operational environment and information and skills about stress, trauma and resilience in the body. The researchers suggest that mindfulness training may help anyone who must maintain peak performance in the face of extremely stressful circumstances.

Another study showing the cognitive benefits of meditation has revealed benefits to perception and attention. The study involved 30 participants attending a three-month meditation retreat, during which they attended group sessions twice a day and engaging in individual practice for about six hours a day. The meditation practice involved sustained selective attention on a chosen stimulus (e.g., the participant’s breath). By midway through the retreat, meditators had become better at making fine visual distinctions, and better able to sustain attention during the half-hour test, compared to matched controls. Those who continued practicing meditation after the retreat still showed improvements in perception when they were retested about five months later.

Great news for those who crave the benefits of meditation but find the thought a bit intimidating! While a number of studies have demonstrated that long-term mindfulness meditation practice promotes executive functioning and the ability to sustain attention, now a small study involving 49 students has found that as little as four sessions of 20 minutes produced a significant improvement in critical cognitive skills, compared to those who spent an equal amount of time listening to Tolkien's The Hobbit being read aloud. Both groups showed similar improved levels of mood, but only the meditation group improved their cognitive scores. While this group improved on all cognitive tasks, they did dramatically better when under stressful conditions, such as provided by increasingly challenging time-constraints, and particularly in the areas of attention and vigilance. Mindfulness training, as given here, focuses on breathing, letting go one’s thoughts, releasing sensory events that distract. It should be noted that no one is suggesting four days training produces a permanent effect! But it is encouraging to think that benefits might be achieved so quickly. The training also reduced fatigue and anxiety.

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 HA, Rawlings NB, Francis AD, Greischar LL, Davidson RJ. Mental Training Enhances Attentional Stability: Neural and Behavioral Evidence. J. Neurosci. [Internet]. 2009 ;29(42):13418 - 13427. Available from: http://www.jneurosci.org/cgi/content/abstract/29/42/13418

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 AW, Lepore N, Gaser C. The underlying anatomical correlates of long-term meditation: Larger hippocampal and frontal volumes of gray matter. NeuroImage [Internet]. 2009 ;45(3):672 - 678. Available from: http://www.sciencedirect.com/science/article/B6WNP-4VCH6WN-8/2/fa4f305302758ca5631926fc44a5350f

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 MA. The enhancement of visuospatial processing efficiency through Buddhist Deity meditation. Psychological Science: A Journal of the American Psychological Society / APS [Internet]. 2009 ;20(5):645 - 653. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19476594

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. “Thinking about Not-Thinking”: Neural Correlates of Conceptual Processing during Zen Meditation. PLoS ONE [Internet]. 2008 ;3(9):e3083 - e3083. Available from: http://dx.doi.org/10.1371/journal.pone.0003083

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 AP, Krompinger J, Baime MJ. Mindfulness training modifies subsystems of attention. Cognitive, Affective & Behavioral Neuroscience [Internet]. 2007 ;7(2):109 - 119. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17672382

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 JA, Lutz A, Schaefer HS, Levinson DB, Davidson RJ. Neural correlates of attentional expertise in long-term meditation practitioners. Proceedings of the National Academy of Sciences [Internet]. 2007 ;104(27):11483 - 11488. Available from: http://www.pnas.org/content/104/27/11483.abstract

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 HA, Lutz A, Greischar LL, Francis AD, Nieuwenhuis S, Davis JM, Davidson RJ. Mental Training Affects Distribution of Limited Brain Resources. PLoS Biol [Internet]. 2007 ;5(6):e138 - e138. Available from: http://dx.doi.org/10.1371/journal.pbio.0050138

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. Meditation alters perceptual rivalry in Tibetan Buddhist monks. Current Biology [Internet]. 2005 ;15(11):R412-R413 - R412-R413. Available from: http://www.cell.com/current-biology/fulltext/S0960-9822(05)00558-0

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