Just a month of meditation training alters brain wiring in ways that could open the door to new treatments for mental disorders, research has shown.
Scientists looked at the effects of integrative body-mind training (IBMT) on two groups of university students.
After just four weeks, or 11 hours, of training scans showed physical changes in the brains of the volunteers.
Nerve fibres, known as 'white matter', became denser, providing greater numbers of brain-signalling connections. At the same time there was an expansion of myelin, the protective fatty insulation surrounding nerve fibres.
The effects were seen in the anterior cingulate cortex region of the brain, which helps regulate behaviour.
Poor nerve activity in this part of the brain is associated with a range of mental problems, including attention deficit disorder, dementia, depression, and schizophrenia.
The study built on previous research based on magnetic resonance imaging (MRI) scans that first highlighted brain changes induced by IBMT. Scientists revisited results from two 2010 studies, taking a closer look at what the scans revealed.
One involved 45 US students from the University of Oregon; the other 68 students from China's Dalian University of Technology.
The researchers found greater density of axons, or nerve fibres, after two weeks of IBMT training, but no change in myelin formation.
After a month both increases in axon density and myelin were seen.
Students undergoing IBMT also reported improvements in mood, experiencing reduced levels of anger, depression, anxiety and fatigue. They also had lower levels of the stress hormone cortisol.
Study leader Professor Michael Posner, from the University of Oregon, who carried out the original US research, said: 'This study gives us a much more detailed picture of what it is that is actually changing.
'We did confirm the exact locations of the white-matter changes that we had found previously. And now we show that both myelination and axon density are improving.
'The order of changes we found may be similar to changes found during brain development in early childhood, allowing a new way to reveal how such changes might influence emotional and cognitive development.'
The findings are reported in the journal Proceedings of the National Academy of Sciences.
In their conclusions, the scientists wrote: 'This dynamic pattern of white matter change involving the anterior cingulate cortex, a part of the brain network related to self-regulation, could provide a means for intervention to improve or prevent mental disorders.'
Neuroscientist Dr Elena Antonova, from the Institute of Psychiatry, King's College London, said: 'The findings of this study are potentially good news for all of us. If as little as 11 hours of mindfulness training makes the brain wiring more prolific and better insulated, then simply by being mindful, which is accessible to anyone at any time, we might enjoy a lifetime of mental clarity and emotional stability.'
Dr Eva Cyhlarova, head of research at the Mental Health Foundation, said: 'This study is another example of brain neuroplasticity in adulthood and how with some simple techniques we can affect its structure as well as its function.
'Furthermore, these changes appear to lead to improvements in mood, which is consistent with self-regulation being a core feature of many mental health problems.
'If such a simple and cheap method of training shows positive results, there is hope for more people with mental health problems to be able to access support through affordable interventions.'