Transcranial Magnetic Stimulation of the Default Mode Network to Improve Sleep
Abstract
This project will address the Topic Area of Sleep Disorders. Sleep problems represent one of the major health issues facing the U.S. military. In fact, about 42% of military personnel regularly obtain 5 hours of sleep or less per night, a level that is insufficient to sustain optimal alertness, vigilance, and decision-making. As many as 85% of military Service members meet criteria for a clinically relevant sleep disorder, with approximately 25% having a primary complaint of insomnia (i.e., difficulty falling or staying asleep). Medications such as sleeping pills may be effective in some situations, but may also be contraindicated in operational environments due to their many side effects and other adverse health issues. Because sleep problems are among the top complaints of military personnel and can have profound impacts on force readiness, it is imperative that novel approaches to minimizing insomnia and sleep problems be developed. Difficulty falling and remaining asleep, known as insomnia, is generally believed to be caused by excessive arousal of the brain and body. Most people with insomnia complain that they “can’t turn off” their thoughts, ruminations, and internal dialog. Rather than transitioning normally and quickly from wakefulness to sleep, the insomniac instead replays internal conversations, images, and repetitive worries that maintain a self-perpetuating cycle of self-referential thought and arousal. Brain imaging research has shown that these same internally focused self-reflective thoughts tend to activate a core system in the brain known as the Default Mode Network (DMN). The DMN is usually active when a person is internally focused, such as during daydreaming or mind wandering, but tends to be deactivated when the brain is focused on the external environment. We hypothesize that excess activation and connectivity of this brain network may perpetuate internal conversations, worry, and rumination, preventing the insomniac from falling asleep quickly and remaining asleep. Therefore, the goal of the present study is to use a brain stimulation technique known as transcranial magnetic stimulation (TMS) to target the DMN and slightly reduce its activation before bed. This should result in an easier time falling asleep. For this study, we will recruit 20 healthy individuals and have them come to sleep in the lab on two occasions. On one occasion, they will be stimulated with a type of TMS called continuous theta burst stimulation (cTBS), which will be targeted toward their DMN. They will then try to sleep in the lab while we record their brain waves using a technique known as polysomnography (PSG). On the other occasion, these same individuals will undergo the same procedure, but the TMS machine will be in a deactivated mode to present a “sham” stimulation. Participants will again try to sleep in the lab following the sham treatment while being recorded with PSG. Neither the participants nor the experimenters will know which condition the participant is receiving at the time. This will only be revealed later. Additionally, all participants will receive a brain scan just before and just after the TMS procedures so that we can examine changes in brain connectivity and chemistry. We expect that our participants will sleep better following the cTBS than following the sham condition and that this will be associated with measurable differences in their brain connectivity and brain chemistry. If effective, this project would have identified an innovative and novel approach for improving sleep without using drugs. This would represent an important discovery for sleep science but would also suggest a potential treatment for military personnel with sleep problems. The project would represent a first step in developing this new potential treatment and would provide crucially important preliminary data to guide the design of much larger clinical trials to fully explore the possibilities of thi
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010173
Entities
People
- William D. Killgore
Organizations
- United States Army
- University of Arizona