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Here we propose that long-term pain alters the functional connectivity of cortical regions known to be active at rest, i.e., the components of the "default mode network" (DMN).

This DMN (Raichle et al., 2001; Greicius et al., 2003; Vincent et al., 2007) is marked by balanced positive and negative correlations between activity in component brain regions. In several disorders, however, this balance is disrupted (Fox and Raichle, 2007).

Using well validated functional magnetic resonance imaging (fMRI) paradigms to study the DMN (Fox et al., 2005), we investigated whether the impairments of chronic pain patients could be rooted in disturbed DMN dynamics.

Studying with fMRI a group of chronic back pain (CBP) patients and healthy controls while executing a simple visual attention task, we discovered that CBP patients, despite performing the task equally well as controls, displayed reduced deactivation in several key DMN regions.

These findings demonstrate that chronic pain has a widespread impact on overall brain function, and suggest that disruptions of the DMN may underlie the cognitive and behavioral impairments accompanying chronic pain.

[Note: To read more, see news release on this study, "Chronic Pain Harms the Brain."]

Source: The Journal of Neuroscience, February 6, 2008, 28(6):1398-1403; doi:10.1523/JNEUROSCI.4123-07.2008, by Marwan N. Baliki MN, Geha PY, Apkarian AV, Chialvo DR. Departments of Physiology, Anesthesia, and Surgery, and Lurie Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. [E-mail: d-chialvo@northwestern.edu]