Optogenetics Pinpoint Neurons That Drive REM Sleep

06 Feb Optogenetics Pinpoint Neurons That Drive REM Sleep

Posted at 23:58h in Author Interviews, Brigham & Women's - Harvard, PNAS, Sleep Disorders by Marie Benz MD FAAD

MedicalResearch.com Interview with:
Christa Van Dort PhD
Department of Anesthesia, Critical Care, and Pain Medicine,
Department of Brain and Cognitive Sciences,
Picower Institute for Learning and Memory,
Massachusetts General Hospital, Harvard Medical School Boston, MA, 02114

Medical Research: What is the background for this study? What are the main findings?

Dr. Van Dort: Sleep is crucial for survival and maintenance of health. Inadequate sleep and sleep disorders impair many brain and body functions such as executive function, the immune system and memory consolidation. The benefits of sleep are dependent on normal sleep physiology and patterns. Natural sleep is composed of non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep alternating every 90 min in humans. Each stage provides different benefits, for example deep NREM sleep is associated with feeling rested and REM sleep is important for learning. Current sleep aids do not effectively restore normal sleep physiology or timing and as a result do not fulfill the important functions of natural sleep. To develop new strategies for reproducing natural sleep, we aimed to understand each component of sleep (NREM and REM sleep) individually and then in combination. Cholinergic neurons have been hypothesized to control REM sleep for many years but no one had been able to test this directly due to limited methodology. Optogenetics solved this problem by giving us the ability to activate selectively the cholinergic neurons in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT).

The primary finding of this study was that cholinergic neurons in the PPT and LDT are sufficient to drive REM sleep from NREM sleep. These cholinergic neurons were important for initiation of REM sleep but not the duration of REM sleep. Understanding REM sleep control is an important first step in reproducing normal sleep patterns and by itself could enhance learning and memory.

Medical Research: What should clinicians and patients take away from your report?

Dr. Van Dort: The long term goal of this research is to apply sleep state control to humans so that we can reproduce normal sleep patterns in people with insomnia and improve their overall health. While it’s not possible to control REM sleep via optogenetics in humans yet, this research lays the foundation for discovery of future treatments for insomnia by telling us which cell types and brain regions are important to regulate REM sleep.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Van Dort: Future studies that carefully examine the role of crucial brain regions in control of NREM and REM sleep will provide key steps to reproduce natural sleep patterns in humans.

Citation:

Optogenetic activation of cholinergic neurons in the PPT or LDT induces REM sleep

Christa J. Van Dort,^a,b,c,1 Daniel P. Zachs,^a,b,c Jonathan D. Kenny,^a,b,c Shu Zheng,^b Rebecca R. Goldblum,^b,c,d Noah A. Gelwan,^a,b,c Daniel M. Ramos,^b,c Michael A. Nolan,^b,c,d Karen Wang,^b,c Feng-Ju Weng,^b,e Yingxi Lin,^b,e Matthew A. Wilson,^b,c and Emery N. Brown^a,b,d,f,1