Meditation modifies brain networks

It has been found that certain areas turn on and certain other areas turn off when you engage in a cognitive task (Raichle et al. (2001)). It has been thought that the brain areas that turn off when you do a task are involved in mind-wandering (see e.g., Christoff et al., 2009) and self-absorbed thought, because that is what you tend to be doing when you're in a psychology experiment and you're not actually doing a task. Now this suggests that meditation, which is intended to decrease mind-wandering and especially self-absorption, may have an influence on this. Indeed, a study by Brewer and colleagues last year found that this "day-dreaming" brain network was relatively deactivated in experienced meditators during their meditation practice. They also found that the brain areas that tended to couple together were affected in meditators compared to control participants. The posterior cingulate, dorsal anterior cingulate, and dorsolateral prefrontal cortices which are often implicated in cognitive control, were more strongly connected with each other not just during meditation but even when the meditators were not practicing. Of course it should be noted that you cannot really infer from a brain what is happening in the mind of a person, so we cannot really conclude that meditators are mind-wandering less, but at least the data are consistent with that. And that is good news, because other research has shown that people that mind-wander a lot tend to be less happy (Killingsworth et al (2010)). Another interesting finding in this study was that they looked at the loving kindness meditation and found that the amygdala, which is typically associated with fear responses, was deactivated in meditators.

A very recent study by Josipovic and colleagues found also that the organization of brain networks changed as meditators practised different types of meditation. While the study by Brewer focused on practitioners of insight meditation, this study focused on Tibetan Buddhist practitioners. This study also looked at how the "mind-wandering-mode" of your brain (also known as the "default mode") turns on, but compared different types of meditation to one another. This was motivated by the idea that as you become more proficient in meditation, you may actually be always on-task, and always be mindful and aware. Josipovic and colleagues compared no meditation, concentration meditation and non-dual awareness meditation in a group of very experienced meditators (8-22 years of practice). During the whole study they were looking at a red fixation dot. They found that during concentration meditation, the two modes of the brain (default mode and task mode) were more correlated than during fixation, but during non-dual awareness meditation they were less correlated. The difference between concentration meditation and non-dual awareness is, the authors claim, that in concentration meditation you focus on the world, whereas during non-dual awareness the outside world and the inside world become one. Of course we don't know what participants are really doing during these meditations, but I think that studying the natural modes of function in which the brain settles during different meditative states is a very promising avenue of research.