Key Brain Circuits Activate When Your Mind is at Rest
What's your brain up to when you close your eyes?
Posted May 09, 2012
People with depression commonly report that their minds are unusually restless, that they wake early in the morning with out of place thoughts that won't stop coming, worries about things they can't do anything about, whether related to their relationships or work or health. During the daytime too, they often feel that their minds won't stop going over and over the same thoughts--sometimes to the point that they have difficulty paying attention to the here-and-now of their own lives. They are 'spaced out,' perhaps, they 'live in their own world.' This type of experience isn't unique to depression, of course, it is also found in various anxiety disorders, such as social anxiety disorder, and in eating disorders too, for instance anorexia.
We are in a new age of psychiatry these days, reaching toward biological explanations for psychiatric disorders. In particular, we are looking for brain circuits that may explain symptoms.
Over the years, in my life as a research psychiatrist, I've done innumerable medication studies, often comparing active medications to placebo in the treatment of various types of depression. Several years ago, when a new MRI machine was installed at the NY State Psychiatric Institute, I reached out to a group of brain imaging researchers newly arrived at the Institute, to ask whether we could combine a clinical trial with repeated brain imaging. Suffice it to say, after a lot of work and terrific collaboration, we were able to get funding for such a project, and after several years--and a lot more work--we were able to complete our study, with 'serial' imaging of depressed patients before and after 10 weeks of treatment with an antidepressant or placebo. For what it's worth, there are only a (small) handful of such studies in the world psychiatric literature, so I'd like to thank my many collaborators in this study, particularly Drs. Bradley Peterson and Jonathan Posner, and my colleagues in the Depression Evaluation Service, especially Drs. Patrick McGrath, Jonathan Stewart, and Deborah Deliyannides, where we treat these patients.
Anyhow, what did we find?
For this first paper, we were looking at what has been called the 'default mode network,' or the DMN, a series of brain centers that--interestingly enough--become MORE active when your mind is at rest.
Not suprisingly, before treatment we found that patients with dysthymia (chronic mild depression) had elevated DMN activity compared to people without a history of depression. The same has been found in other forms of depression, such as acute major depression. But interestingly, after treatment with medication--but not with placebo--the activity of the DMN decreased to the level found in people with no history of depression. In brief, their DMN activity was now apparently NORMAL!
And, if you asked them, the patients in this study--like the patients I treat in my practice--generally reported that their thoughts were no longer rushing out of control, no longer waking them at inopportune moments or distracting them during the daytime.
So, am I just pushing medication on all my depressed patients?
Actually, I'm probably more enthusiastic about what we call 'behavioral interventions.' Most notably, things like meditation, yoga, exercise, relaxation training. Take meditation: recent studies suggest that people who are trained meditators are able to 'modulate' the effect of their DMNs! By disciplined training they are able to turn down those brain circuits. Can people with depression be taught to do the same thing? Studies are underway to test this.(Meds have their place, of course, and sometimes are necessary. but they certainly aren't a be-all or end-all of treatment!)
As I've pointed out in other postings in my PsychologyToday.com blog Heal Your Brain, we are in the age of the New Neuropsychiatry, a discipline that is integrating mind, body, and brain. And has the utmost respect for the idea that the brain is ever-changing, that 'neuroplasticity' continues throughout life.The idea is that any number of types of interventions can affect the structure, function, and connectivity of the brain. Not just the SSRI medications, not just cognitive behavioral therapy, or psychoanalytic psychotherapy, but potentially many different kinds of interventions.
The buzzword these days in the age of New Neuropsychiatry is 'tuning circuits.'
Here with the Default Mode Network, we have an opportunity to figure out whether this is a circuit in need of tuning. It seems like a pretty good candidate, since DMN activity is increased in depression, anxiety disorders, bipolar disorder, and schizophrenia, among other conditions.
Our study is a first step that suggests that it is possible to tune the circuit with medicine. But other studies need to be done, of other medications, with CBT, with meditation, exercise, even computer-based cognitive retraining.
We're just at the beginning of this new age...and there's a lot of great work still to be done!
Posner J, Hellerstein DJ, Klahr K, Stewart JW, McGrath PJ, Peterson BS. Antidepressants normalize the default mode network in patients with dysthymia. JAMA Psychiatry 2013;70(4):373-382