Graphical Abstract Highlights d GABAergic neurons in the SC receive direct input from RGCs d Acute dark induction of wakefulness requires SC GABAergic neurons d VTA dopaminergic neurons receive direct innervations from GABAergic neurons in the SC d VTA dopaminergic neurons are necessary for acute dark induction of wakefulness

Hypersomnolence disorder (HD) is characterized by excessive sleep, which is a common sequela following stroke, infection, or tumorigenesis. HD is traditionally thought to be associated with lesions of wake-promoting nuclei. However, lesions of a single wake-promoting nucleus, or even two simultaneously, did not exert serious HD. Therefore, the specific nucleus and neural circuitry for HD remain unknown. Here, we observed that the paraventricular nucleus of the hypothalamus (PVH) exhibited higher c-fos expression during the active period (23:00) than during the inactive period (11:00) in mice. Therefore, we speculated that the PVH, in which most neurons are glutamatergic, may represent one of the key arousal-controlling centers. By using vesicular glutamate transporter 2 (vglut2Cre) mice together with fiber photometry, multichannel electrophysiological recordings, and genetic approaches, we found that PVHvglut2 neurons were most active during wakefulness. Chemogenetic activation of PVHvglut2 neurons induced wakefulness for 9 hr, and photostimulation of PVHvglut2→parabrachial complex/ventral lateral septum circuits immediately drove transitions from sleep to wakefulness. Moreover, lesioning or chemogenetic inhibition of PVHvglut2 neurons dramatically decreased wakefulness. These results indicate that the PVH is critical for arousal promotion and maintenance.

Intracranial mature teratoma is a rare lesion in adults. Despite several intracranial mature teratomas had been reported not to be located at the midline region, no one was found to be within cerebral falx. Herein, we reported a 37-year-old female patient with an intracranial mature teratoma confined within frontal cerebral falx. Her main complaint was intermitted headache, which could not be relieved recently by taking painkiller. Excepting for mild papilledema, we did not find positive neurological signs on physical examination. CT scanning showed it was a round homogenously hypodense lesion with hyperdense signal at its rim. MRI revealed the lesion was 3.5cm×3.6cm×4.5cm in volume, with uniformed hypointensity on T1WI, hyperintensity on T2WI and enhancement in the capsule. It was totally removed via inter-hemispheric approach, and we found the lesion was confined within the frontal cerebral falx. Postoperatively, it was proved histologically to be a mature teratoma. At three years of fellow up, neither neurological deficits nor recurrent sings on MRI was found. To our best knowledge, this is the first case of intracranial mature teratoma within cerebral falx.

BackgroundHypersomnia is a common and highly impairing symptom marked by pathological excessive sleepiness, which induces suboptimal functioning and poor quality of life. Hypersomnia can be both a primary (e.g., hypersomnolence disorder) and secondary (e.g., tumors, and head trauma) symptom of disorders. However, its underlying mechanisms remain largely unknown.Case PresentationWe report that three clinical cases with lesions around the paraventricular nucleus of the hypothalamus (PVH) area showed excessive daytime sleepiness and a prolonged nocturnal sleep lasting more than 20 h per day. Sleep architecture and subjective daytime sleepiness were examined by polysomnography. These cases were presented with stroke, myelin oligodendrocyte glycoprotein (MOG) antibody associated disorders and neuromyelitis optical spectrum disorder (NMOSD), respectively. Magnetic resonance imaging (MRI) showed lesions around the PVH area in all these three patients. After treatment of their primary disorders, their excessive sleep decreased as the PVH area recovered.ConclusionOur findings suggest that the PVH may play an essential role in the occurrence of hypersomnia.