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| A Buddhist monk from the Thai forest tradition in a magnetoencephalography (MEG) facility. This image was created using a generative artificial intelligence program for illustrative purposes. Image Credit: AI prompt by Karim Jerbi |
To decode the subtle mechanisms of the meditative state, the researchers worked with 12 monks of the Thai Forest Tradition at Santacittarama monastery outside Rome, who between them had practiced an average of more than 15,000 hours of meditation each.
At the MEG lab in Chieti-Pescara, in Abruzzo, the monks' brains were scanned while they meditated. Two techniques of meditation were studied:
Samatha, a focused attention technique that concentrates on a specific object (such as breathing) to stabilize the mind and achieve a deep state of calm; and
Vipassana, an open-monitoring technique that involves observing the present moment (sensations, thoughts, emotions) without selection or judgment to understand the nature of the mind.
“With Samatha, you narrow your field of attention, somewhat like narrowing the beam of a flashlight; with Vipassana, on the contrary, you widen the beam,” said Jerbi, one of the study's co-authors.
“Both practices actively engage attentional mechanisms," he said. "While Vipassana is more challenging for beginners, in mindfulness programs the two techniques are often practiced in alternation."
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Karim Jerbi, professor of psychology at the Université de Montréal
Photo Credit: Amélie Philibert, Université De Montréal
Criticality: the happy medium
In their study, Jerbi and his co-researchers found that both types of meditation produce significant changes in brain dynamics but not in the same way, particularly when it comes to criticality.
A concept borrowed from statistical physics that has been applied in neuroscience for 20 years; criticality refers to an optimal balance between order and chaos. It’s often described as the brain’s “sweet spot” for efficient functioning.
“A brain that lacks flexibility adapts poorly, while too much chaos can lead to malfunction, as in epilepsy,” Jerbi explained.
“At the critical point, neural networks are stable enough to transmit information reliably, yet flexible enough to adjust quickly to new situations. This balance optimizes the brain’s processing, learning and response capabilities.”
In other words, the closer the brain comes to a state of criticality, the more efficiently, flexibly and responsively it can function. This increases capabilities such as task-switching and information storage.
Of the two types of meditation, Vipassana brings the practitioner closer to this critical point, while Samatha produces a somewhat more stable and focused state.
Treating anxiety and depression, too
Jerbi believes the benefits of meditation are not limited to its duration. This is why meditation-based interventions—for conditions such as anxiety, stress and depression—have gained popularity, he said.
In the case of depression, for example, increased brain flexibility can help reduce the activity of the brain circuits associated with rumination, or thoughts going around in circles. Being able to voluntarily direct one’s attention also allows for better emotional self-regulation, a central mechanism of psychological well-being.
“Since meditation is an active state that engages attentional processes; it affects several aspects of brain function, leading to improved well-being and a reduction in stress and symptoms of anxiety and depression,” Jerbi said.
It also seems you don’t have to be an expert with 15,000 hours of practice to benefit from meditation, even though "the brain of a meditation novice doesn’t instantly achieve the states observed in an expert,” Jerbi said.
“And, as with sports or hypnosis, motivation and individual predisposition play a key role.”
Measuring magnetic fields
To study the monks' meditating brains, the researchers used magnetoencephalography, a neuroimaging technology that measures the magnetic fields generated by neural electrical activity.
This non-invasive technique can monitor the brain in real time with exceptional spatial and temporal resolution.
MEG scanners are highly specialized instruments found at only a few university centers in the world, including at Université de Montréal. They are particularly well-suited to studying meditation because they can track the fine-grained brain dynamics of meditative states with unparalleled precision.
The research team also used machine-learning algorithms to analyze the data—not to determine the state of each brain (which they already knew), but to distinguish brain activity during Samatha, Vipassana, and rest.
“This unique combination," said Jerbi, "allowed us to document with unprecedented precision what happens in the meditating brain – and to shed new light on a thousand-year-old tradition."
Published in journal: Neuroscience of Consciousness.
Authors: Annalisa Pascarella, Philipp Thölke, David Meunier, Jordan O’Byrne, Tarek Lajnef, Antonino Raffone, Roberto Guidotti, Vittorio Pizzella, Laura Marzetti, and Karim Jerbi
Source/Credit: Université de Montréal | Béatrice St-Cyr-Leroux
Reference Number: ns010526_01