How Does Insomnia Affect Brain Function?

After a night of sleep deprivation, the executive control network had a greater decrease in activity during sleep for all participants. The inferior parietal lobule, the posterior cingulate, and the superior medial frontal cortex also had greater deactivation after a night of sleep deprivation for all participants. The sole difference between groups was that the thalamus became less active after a night of sleep deprivation in the controls, compared with patients with insomnia.

Dr. Buysse’s group then administered a course of CBT-I to 13 people with insomnia. When they compared wake and non-REM sleep before and after CBT-I, they found lower metabolism during sleep in the posterior cingulate and precuneus after treatment, compared with before treatment. Treatment thus helped to establish a “more normal pattern,” said Dr. Buysse.

Together, these findings indicate that insomnia can be characterized as a disorder of network dysregulation across sleep–wake states. Treatments for insomnia “seem to work by downregulating brain networks related to self awareness, salience detection, and cognitive control during sleep,” said Dr. Buysse.

Potential Treatment Mechanisms
The best insomnia treatments would address sleep disruption and network dysregulation, he added. Research indicates that meditation and mindfulness strategies affect function in the default mode network, and these approaches can reduce insomnia effectively.

In addition, transcranial magnetic stimulation (TMS) can alter activity in the default mode and executive control networks in a noninvasive way. This technique can improve aspects of cognitive function and suppress some of the self-referential thinking associated with insomnia. “Most of us probably don’t think of TMS as a treatment for insomnia, but maybe that’s an avenue that we’ll need to explore,” said Dr. Buysse.

A major challenge, however, is the small number of certified providers of sleep medicine, compared with the number of people with insomnia. To meet this challenge, neurologists are developing strategies to broaden the reach of effective treatments, said Dr. Buysse. Some strategies involve social media, while others rely on health care providers who are not sleep specialists, such as primary care physicians and nurses.

—Erik Greb