AUTHOR=Ma Caifen , Zhou Ning , Ma Kang , Niu Jiandong , Mi Ting , He Zhenquan , Wen Yujun , Liu Chunhong , He Zhongyi , Niu Jianguo 

TITLE=Neural pathways from hypothalamic orexin neurons to the ventrolateral preoptic area mediate sleep impairments induced by conditioned fear

JOURNAL=Frontiers in Neuroscience

VOLUME=Volume 17 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2023.1122803

DOI=10.3389/fnins.2023.1122803

ISSN=1662-453X

ABSTRACT=Fear and sleep impairments often co-exist, but the underlying mechanisms remain unclear. In the present study, the neural pathways by which conditioned fear induces sleep impairments were identified. The retrograde tracing technique was used to demonstrate the projections from the orexin-containing hypothalamic neurons to the ventrolateral preoptic area (VLPO). By combining retrograde tracing technique and immunofluorescence staining, we found that orexin-VLPO neural pathways are activated by conditioned fear. With optogenetics and cortical electroencephalography (EEG), it was observed that the optogenetic activation of orexin neurons or orexin-VLPO neural pathways significantly decreases sleep time and increases wakefulness time in mice with conditioned fear. A significant decrease in sleep time and an increase in wakefulness time were observed after the injection of orexin-A into the VLPO. The effects of orexin-A in the VLPO were blocked by a pre-administrated dual orexin receptor antagonist (DORA). The results suggest that neural pathways from hypothalamic orexin neurons to the VLPO mediate sleep impairments induced by conditioned fear.