Neuroscience looks at tthe remarkable effects of meditation on the brain
12/16/03 11:48 AM
Loc: Seattle, WA
The remarkable effects of meditation on the brain
We think of the seat of the soul as the brain, in concert with the rest of the nervous system. The Dalai Lama speaks of a "luminous consciousness" that transcends death and which he thinks might not have brain correlates, but we believe even 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 and virtuous people light up? How are the qualities of happiness, serenity and loving kindness that arise from 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.
From New Scientist Magazine 24 May 03
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