Neuro Deep Dive: Brain Networks You Should Know About
- Katya Bownas RN, PMH-BC
- Feb 5
- 3 min read
For years scientists have worked to understand the human brain; how it functions, why it malfunctions, and how to remedy dysfunction. As the world of neuroscience progresses, we continue to learn more and more about the brain and how its structures dictate our cognition, emotions, and actions. Understanding the brain’s networks and connections helps us better understand how to treat mental and physical health conditions and reach optimal brain performance. It is estimated that around 21 million adults in the United States have had at least one major depressive episode, and in 2017 the WHO reported depression as the leading cause of disability worldwide.
In the recent past, it was believed that the primary causes of conditions such as depression and anxiety were imbalances in neurotransmitters (dopamine, serotonin, norepinephrine, etc.), causing symptoms such as fatigue, executive dysfunction, and worry or dread. New discoveries in neuroscience tell us that these symptoms may actually be a result of dysfunction in certain key brain networks responsible for regulating these aspects of mood, attention, and activity. There are three networks you should know about that play important roles in cognition and mental health: the central executive network (or frontoparietal network), the salience network, and the default mode network.
The central executive network is believed to be responsible for managing the demands of cognitively challenging, goal-oriented tasks and, as the name implies, executive functioning (aka your ability to complete an action). When this network is impaired due to acute or chronic stress, environmental, or genetic factors, it may result in inability to follow through on a task, perceived lack of motivation, impulse control issues, and other symptoms. Dysfunction within this network has been found in many psychiatric and neurological conditions from depression to Alzheimer’s to autism, and research into the implications of and treatment options for dysfunction in this network is on-going.
The default mode network is active and in use during relaxation, when a person is daydreaming, meditating, or not actively performing cognitive or physical tasks. It is the “default”, chill setting of your brain. It is important that this network functions adequately and that we are able to utilize these pathways during times of rest - if the brain is unable to make use of this more downregulated network, it can lead to hyperactivation and symptoms such as restlessness, anxiety, and worry. Alternatively, if the brain is not able to switch out of this default mode, we may see symptoms like the ones named above: an inability to “get up and go” as well as difficulties with attention and concentration.
The salience network is a key player in allowing your brain to shift between the CEN and the DMN. The salience network is sometimes referred to as the “moderator” or “switch” of the brain, switching between the more active CEN and the DMN as needed based on external and internal stimuli. The word salience means importance, so it is this network’s job to determine what tasks, activities, or other inputs are important to us, and respond accordingly. Disruption or misfiring in the salience network can be connected to many maladaptive behaviors, impairments, and symptoms in disorders such as depression, chronic pain, anxiety, insomnia, and as well as many other psychiatric disorders.
Disruption in these networks can occur for a variety of reasons, including physical trauma (TBI, stroke), chronic stress, psychiatric conditions, genetics and neurodegenerative diseases. These disease and injury processes can cause these networks to falter by acting on different components, such as neurotrophic (brain protecting) factors and neural plasticity. Once disruption occurs within these networks, it can be difficult to return to baseline functioning without outside intervention to help restore communication and growth within the brain.
Treatments that help to improve cortical excitability, communication, and plasticity such as neurofeedback, ECT, and transcranial magnetic stimulation (TMS) - have shown great promise in improving the functioning of these essential networks and decreasing patients’ symptoms. TMS in particular is proving to be highly effective at treating many challenging and debilitating mental health conditions with particular efficacy in the treatment of treatment resistant Major Depressive Disorders. Lifestyle factors such as diet, exercise, sleep, and hydration are also key players in overall brain health and are essential adjunctive care when considering a more involved treatment.
Stay tuned for our next newsletter in which we will be covering neural plasticity, neurotrophic factors, and their role in healthy brain functioning.
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