Research shows that around 50% of our awake time we are mind-wandering and one of the reasons why that happens is because our brain has a default mode network. The concept of a default mode network was developed after researchers inadvertently noticed surprising levels of brain activity in experimental participants who were supposed to be “at rest”, so they were not engaged in a specific mental task, but just resting quietly. It’s the network involved in planning, daydreaming and ruminating. It’s also called the “narrative circuitry” because also becomes active when you think about yourself and other people (adding histories to it).
The default mode network is useful because it’s involved in our memory helping us to make a model of the world, predict the future, based on past events. But it has also its drawbacks. Recent research has associated the default mode network with unhappiness, depression, anxiety, schizophrenia, attention-deficit hyperactivity disorder (ADHD) and Alzheimer’s Disease.
Researchers found that the default network is less active during meditation (so avoiding rumination and mind-wandering) and show a greater functional connectivity between this network and regions of the central executive network, related to attention management, suggesting a greater capacity to monitor and manage mind-wandering and self-referential thinking.
How mindfulness practices change the brain?
There is evidence that mindfulness meditation causes changes in the structure and function of brain regions involved in the regulation of attention, emotional regulation, and self-awareness.
One example is the research developed by Dr. Sara Lazar and her team using one experimental group that had an 8 week mindfulness meditation intervention and a control group without. The team studied the differences in amount of grey matter using fMRI neuroimaging techniques. The results showed that as opposed to the control group, the mindfulness training group revealed an increased grey matter (compared to their own baseline before the training) in four different regions:
- the posterior cingulate (associated with mind-wandering and self-relevance)
- left hippocampus (learning and memory)
- temporo parietal junction (helps with empathy and compassion)
- pons (helps in communication between stem and cortex as well as sleep).
Results also demonstrate a decreased amygdala grey matter (area of the brain connected with fear and perceived stress). These changes in the brain structure are coherent with the feedback reported by the participants that described an increase on life quality as well as a decrease on anxiety and stress, mind wandering and insomnia. They also measure cortisol (a stress hormone) and found lower levels of cortisol within participants under mindfulness intervention.
How does the brain change?
If some years ago it was thought that once our “child’s brain” was developed, everything started to decline, we now know that it is not exactly like that. Our brain has the ability to change its shape and function using a phenomenon called neuroplasticity. This means, for example, that grey matter can thicken or shrink and that the connections between neurons can be strengthened or new connections can be created. This also means that our brain structure and activation can be changed according to the experiences we have or even the training we give. So, the same kind of mechanisms that we can use to develop our memory or learn new languages can be used for training our attention and promoting our well-being. That’s what we do with mindfulness practices.
“Repeat those behaviours that are healthy for your brain and break those behaviours and habits that are not. Practice… and build the brain you want”
Lara Boyd, PhD, University of British Colombia