Monks have been meditating on mountaintops for millennia, hoping to gain spiritual enlightenment. Their efforts have probably enhanced their physical health, too.

Trials looking at the effects of meditation have mostly been small, but they have suggested a range of benefits. There is some evidence that meditation boosts the immune response in vaccine recipients and people with cancer, protects against a relapse in major depression, soothes skin conditions and even slows the progression of HIV.

Meditation might even slow the ageing process. Telomeres, the protective caps on the ends of chromosomes, get shorter every time a cell divides and so play a role in ageing. Clifford Saron of the Center for Mind and Brain at the University of California, Davis, and colleagues recently showed that levels of an enzyme that builds up telomeres were higher in people who attended a three-month meditation retreat than in a control group (Psychoneuroendocrinology, vol 36, p 664).

As with social interaction, meditation probably works largely by influencing stress response pathways. People who meditate have lower cortisol levels, and one study showed they have changes in their amygdala, a brain area involved in fear and the response to threat (Social Cognitive and Affective Neuroscience, vol 5, p 11).

One of the co-authors of Saron's study, Elissa Epel, a psychiatrist at the University of California, San Francisco, believes that meditation may also boost "pathways of restoration and health enhancement", perhaps by triggering a release of growth and sex hormones.

If you don't have time for a three-month retreat, don't worry. Imaging studies show that meditation can cause structural changes in the brain after as little as 11 hours of training. Epel suggests fitting in short "mini-meditations" throughout the day, taking a few minutes at your desk to focus on your breathing, for example: "Little moments here and there all matter."

Jo Marchant is a freelance writer based in London
From New Scientist magazine, 27 August 2011, page 34-35.

About Mindfulness

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What can neuroscientists learn from Buddhists?
Owen Flanagan, professor of philosophy at Duke University, looks at the remarkable effects of meditation on the brain

MEMBERS of my tribe-we call ourselves philosophical naturalists - treat all talk of souls and spirits as metaphorical. We think of the soul as the brain, in concert with the rest of the nervous system. Dalai Lama speaks of a “luminous consciousness” that transcends death and which he thinks might not have brain correlates, but we believe this must be realised neurally.

So an interesting question for neuroscientists is how do the brains of Buddhist practitioners - or indeed any other wise, happy virtuous people-light up? How are qualities of happiness, serenity and loving kindness that the Buddhist practice of mindful meditation reflected in the brain?  How does that subjective experience manifest itself?

Neuroscience is beginning to provide answers. Using scanning techniques such as PET and functional MRI, we can study the brain in action. We now know that two main areas are implicated in emotions, mood and temperament. The amygdala-twin almond-shaped organs in the forebrain-and its adjacent structures are part of our quick triggering machinery that deals with fear, anxiety and surprise. It is likely that these structures are also involved in other basic emotions such as anger. The second area comprises the prefrontal lobes, recently evolved structures lying just behind the forehead. These have long been known to play a major role in foresight, planning and self-control, but are now crucially implicated in emotion, mood and temperament.

With this knowledge in hand, a few prominent neuroscientists have begun to study the brains of Buddhists. The preliminary findings are tantalising. Richard Davidson at the Laboratory for Affective Neuroscience at the University of Wisconsin at Madison has found that the left prefrontal lobes of experienced Buddhist practitioners light up consistently (rather than just during meditation). This is significant, because persistent activity in the left prefrontal lobes indicates positive emotions and good mood, whereas persistent activity in the right prefrontal lobes indicates negative emotion. The first Buddhist practitioner studied by Davidson showed more left prefrontal lobe activity than anyone he had ever studied before.

We can now hypothesise with some confidence that those apparently happy, calm Buddhist souls one regularly comes across in places such as Dharamsala, India-the Dalai Lama’s home-really are happy. Behind those calm exteriors lie persistently frisky left prefrontal lobes. If these findings are widely confirmed, they will be of great importance.

Buddhists are not born happy. It is not reasonable to suppose that Tibetan Buddhists are such a homogeneous biological group that they are, uniquely among humans, born with a “happiness gene” that activates the left prefrontal cortex. The most reasonable hypothesis is that there is something about conscientious Buddhist practice that results in the kind of happiness we all seek. What about the effect of Buddhist practice on the amygdala and other subcortical forebrain circuitry? This circuitry, you will recall, is involved in relatively automatic emotional and behavioural responses.

Now, thanks to important work by Joseph LeDoux at New York University, we know that a person can be conditioned - via their amygdala and thalamus - to be scared of things that really aren’t worth being scared of. We also know that it is extremely hard to override what the amygdala “thinks” and “feels” simply by conscious rational thought.

That said, there is some fascinating early work that suggests Buddhist mindfulness practice might tame the amygdala. Paul Ekman of the University of California San Francisco Medical Center, a renowned researcher on basic Darwinian emotions, is, like Davidson, in the early stages of studying Buddhist practitioners. So far, he has found that experienced meditators don’t get nearly as flustered, shocked or surprised as ordinary people by unpredictable sounds, even those as loud as gunshots. And Buddhists often profess to experience less anger than most people.

I believe research like this will eventually allow us to answer the question of whether Buddhist training can change the way the brain responds - most importantly with negative emotions - to certain environmental triggers.

Antidepressants are currently the favoured method for alleviating negative emotions, but no antidepressant makes a person happy.

On the other hand, Buddhist meditation and mindfulness, which were developed 2500 years before Prozac, can lead to profound happiness, and its practitioners are deeply in touch with their glowing left prefrontal cortex and their becalmed amygdala.