DMN’s Importance in Mental Health

 

    “What is the Default Mode Network”  

Do you ever just drift off and someone suddenly snaps you back to reality. Ever had moments where you just mindlessly think about the future, the past, or even just completely “zone out.” Well, that is caused by your Default Mode Network (DMN), and not many people know the role the DMN plays in the brain. In the field of neuroscience, the default mode network (DMN) is composed of numerous systems in the brain including the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), precuneus, and the angular gyrus. These brain regions play critical roles in memory collection and formation, attention, self-processing, information processing, emotion regulation, metalizing, and various other cognitive tasks. The DMN has been linked to various forms of mental illness, these include patients with Alzheimer’s Disease (AD), along with those who suffer from Parkinson’s Disease (PD), and individuals who suffer from posttraumatic stress disorder (PTSD). Throughout this blog post, we will be looking over the connections between the DMN and mental health problems.

            Looking at the article “Posttraumatic Stress Disorder in Associated with a Dysrhythmia across the Visual Cortex and the Default Mode Network,” Kevin Clancy and his team hypothesized that there is a connection between a decrease in alpha activity and the ability to filter out sensory input across the DMN hubs. The DMN pertains to the resting brain, while alpha activity is the main electrical component of the resting brain. The team found that with increased visual input, patients with PTSD demonstrated reduced alpha frequency directed connectivity with hubs of the DMN, the posterior cingulate cortex (PCC) and the medial prefrontal cortex (mPFC). This presents a therapeutic target for individual who suffer from PTSD. There are numerous studies focused on the connection between the DMN and mental health problems. Looking at the article “Default Mode Network Complexity and Cognitive Decline in Mild Alzheimer’s Disease,” Matthias Grieder and his team examined the connection between two hubs of the DMN in relation to Alzheimer’s Disease. They found disruptions when it comes to functional connectivity between two hubs of the DMN in patients with Alzheimer’s disease (AD), this disruption was a decrease in DMN functional connectivity between the posterior cingulate cortex (PCC) and the right side of the hippocampus. These disruptions lead to disturbance in information processing, transfer of information to different regions in the brain, processing personal information, decision making, spatial cognition, and inevitably, the processing of memories.

            Both these teams and articles focused on the connection between hubs of the DMN and mental illnesses such as PTSD and Alzheimer’s Disease. Clancy and his team looked the decrease in alpha connectivity in the PCC and the mPFC in patients with PTSD whereas Grieder and his team looked at disruptions in connectivity in the PCC and the right side of the hippocampus in patients with Alzheimer’s Disease. Different approaches but both found disruptions in connectivity involved in two different, but very important mental problems. More work is being done regarding the connection between the DMN and other mental problems such as chronic depression and Parkinson’s disease. There is deeper work to be done when looking at the disruptions in connectivity between hubs of the DMN and mental health problems as both teams have found, but for mental problems such as rumination and depression, there are various things to do to stay health. Activities to help boost positivity include reading, hiking, watching the sun or moon rise and set, swimming, and various other positive actives that allows you to leave your mind but do so in a positive way.

References:

Clancy, K. J., Andrzejewski, J. A., Simon, J., Ding, M., Schmidt, N. B., & Li, W. (2020). Posttraumatic Stress Disorder Is Associated with α Dysrhythmia across the Visual Cortex and the Default Mode Network. eNeuro, 7(4), ENEURO.0053-20.2020. https://doi.org/10.1523/ENEURO.0053-20.2020

Grieder, M., Wang, D. J. J., Dierks, T., Wahlund, L. O., & Jann, K. (2018). Default Mode Network Complexity and Cognitive Decline in Mild Alzheimer's Disease. Frontiers in neuroscience, 12, 770. https://doi.org/10.3389/fnins.2018.00770

Buckner R. L. (2013). The brain's default network: origins and implications for the study of psychosis. Dialogues in clinical neuroscience, 15(3), 351–358. https://doi.org/10.31887/DCNS.2013.15.3/rbuckner