Have you ever wondered what your brain does when you are seemingly doing nothing? Obviously, you can decide what you will think of, but you cannot decide to “shut down” the activity of your brain. Researchers have found that even when we are “resting” there are active networks in our brain and that these networks are very similar across people. One of these networks – designated the default mode network (DMN; see image below) – is of particular interest to me (and thousands of neuroscientists) because activity in that network reflects an internal mode of cognition that we are just beginning to understand.
The connections among brain regions in the DMN are active when individuals are not focused on the external environment. We can easily identify DMN connections using our imaging tools when individuals are left to think to themselves undisturbed. For example, listening to the whooshing and loud noises of the fMRI scanner. Now, the phrase “internal mode of cognition” is a very abstract concept and a recent study has provided empirical support that the DMN is one of the most abstract networks in the brain. What does this abstractness mean for thought, cognition, and brain health?
In terms of thought and cognition, research shows that the harder and more cognitively demanding a particular task is, the less the DMN is activated. Interestingly, this decreased activation of the DMN is also affected by popular relaxation methods such as yoga and meditation. Specifically, researchers who examined brain activation during meditation using functional MRI, found decreased activation of regions related to the DMN. The researchers also suggested that meditation training can increase the synchronization of activation between DMN regions that are related to the awareness of the ‘self’.
Focusing on one thing such as breathing during meditation affects the functional connections of the DMN. This has been shown by the Dalai Lama himself as he meditated within an MRI scanner. Researchers are currently looking into the precise mechanisms of how meditation changes the synchronization of neural networks and how this results in improved higher order cognitive and emotional functions.
All in all, don’t be swayed by the seemingly simplistic term of the ‘default mode network.’ The DMN is complex and abstract and we are only beginning to understand how it interacts with other networks in typical brains and in neuropsychiatric disorders. So the next time you lie in bed, thinking that you’re thinking about nothing, remember how complex the intrinsic activity of your brain actually is at that very moment.
Tzipi Horowitz-Kraus is a neuroscientist, as well as member of the Organization for Human Brain Mapping (OHBM) and writes for the Communications/Media Team. The OHBM Media Team brings cutting edge information and research on the human brain to your laptops, desktops and mobile devices in a way that is neurobiologically pleasing. For more information about brain mapping, follow www.humanbrainmapping.org/blog or @OHBMSci_News