Brain pulsations and resting-state lag structure in narcolepsy type 1
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium 7 of Oulu University Hospital
Topic of the dissertation
Brain pulsations and resting-state lag structure in narcolepsy type 1
Doctoral candidate
Licentiate of Medicine Matti Järvelä
Faculty and unit
University of Oulu Graduate School, Faculty of Medicine, Research Unit of Health Sciences and Technology
Subject of study
Medicine
Opponent
Professor Markku Partinen, University of Helsinki
Custos
Professor Vesa Kiviniemi, University of Oulu, Oulu University Hospital
Brain pulsations and resting-state lag structure in narcolepsy type 1
Orexin deficiency alters the pulsations driving the brain’s clearance system and communication between neural networks in type 1 narcolepsy
In individuals with type 1 narcolepsy, the pulsations driving brain fluid circulation and communication between neural networks are altered. While the rapid pulsations of the cerebral arteries were weaker in type 1 narcolepsy, the slow vasomotor pulsations were clearly stronger than in healthy controls and, on the other hand, did not differ in strength from the enhanced vasomotor pulsations observed in sleeping controls. These findings suggest that the disease may also affect the function of the brain’s glymphatic clearance system through brain pulsations. In addition, information transfer between neural networks in type 1 narcolepsy was more monotonous than in healthy controls.
Type 1 narcolepsy is a neurological disease in which orexin-producing neurons in the hypothalamus are destroyed, presumably through an autoimmune reaction. Orexin regulates arousal, helps maintain wakefulness, and stabilizes sleep. Its deficiency causes, among other symptoms, severe daytime sleepiness, fluctuations in arousal state, cataplexy, and fragmented nighttime sleep.
This doctoral dissertation examined how type 1 narcolepsy, due to orexin deficiency, affects functional brain networks and brain pulsations. Brain pulsations move intracranial fluids and thus participate in maintaining fluid circulation as well as act as driving forces for brain clearance. In the study, 23 narcolepsy patients as well as 85 awake and 20 sleeping controls were imaged using fast functional magnetic resonance imaging.
The results suggest that orexin deficiency may alter brain fluid dynamics and possibly thereby affect glymphatic clearance. On the other hand, the reduced ability of neural networks to communicate may partly explain the symptoms of the disease. Better understanding of these mechanisms may in the future help identify new therapeutic targets and increase understanding of brain clearance also in diseases that accumulate toxic metabolic products in the brain.
In individuals with type 1 narcolepsy, the pulsations driving brain fluid circulation and communication between neural networks are altered. While the rapid pulsations of the cerebral arteries were weaker in type 1 narcolepsy, the slow vasomotor pulsations were clearly stronger than in healthy controls and, on the other hand, did not differ in strength from the enhanced vasomotor pulsations observed in sleeping controls. These findings suggest that the disease may also affect the function of the brain’s glymphatic clearance system through brain pulsations. In addition, information transfer between neural networks in type 1 narcolepsy was more monotonous than in healthy controls.
Type 1 narcolepsy is a neurological disease in which orexin-producing neurons in the hypothalamus are destroyed, presumably through an autoimmune reaction. Orexin regulates arousal, helps maintain wakefulness, and stabilizes sleep. Its deficiency causes, among other symptoms, severe daytime sleepiness, fluctuations in arousal state, cataplexy, and fragmented nighttime sleep.
This doctoral dissertation examined how type 1 narcolepsy, due to orexin deficiency, affects functional brain networks and brain pulsations. Brain pulsations move intracranial fluids and thus participate in maintaining fluid circulation as well as act as driving forces for brain clearance. In the study, 23 narcolepsy patients as well as 85 awake and 20 sleeping controls were imaged using fast functional magnetic resonance imaging.
The results suggest that orexin deficiency may alter brain fluid dynamics and possibly thereby affect glymphatic clearance. On the other hand, the reduced ability of neural networks to communicate may partly explain the symptoms of the disease. Better understanding of these mechanisms may in the future help identify new therapeutic targets and increase understanding of brain clearance also in diseases that accumulate toxic metabolic products in the brain.
Created 27.5.2026 | Updated 27.5.2026