Summary: A new study reveals that poor sleep in older adults disrupts the brain’s glymphatic system, responsible for clearing harmful waste and toxins. Researchers found that compromised sleep quality leads to dysfunction in this crucial system, potentially increasing risks for memory decline and cognitive impairments.
Using advanced brain imaging in 72 older adults, the research highlighted that poor sleep negatively impacts connections within brain networks linked to memory performance. These insights emphasize the importance of maintaining good sleep hygiene to support brain health and healthy aging.
Key Facts:
- Sleep and Brain Health: Poor sleep quality impairs the brain’s glymphatic system, crucial for clearing harmful proteins.
- Cognitive Impact: Dysfunctional glymphatic activity due to poor sleep correlates with memory decline in older adults.
- Neural Networks: Sleep quality directly influences brain networks, affecting overall cognitive health and aging.
Source: University of Hong Kong
Poor sleep among older adults is linked to disruptions in the brain’s “waste removal system”, according to researchers at The University of Hong Kong (HKU).
A recent study led by Professor Tatia M.C. Lee, Chair Professor of Psychological Science and Clinical Psychology and May Professor in Neuropsychology at HKU, offers valuable insight into how sleep quality impacts brain functioning.
Many studies have linked poor sleep with a decline in brain functioning. Professor Lee’s team focused on the glial-lymphatic (glymphatic) system, a fluid transport pathway that plays a vital role in clearing waste from the brain. The system’s efficiency is a critical determinant of brain health, particularly in ageing populations.
Professor Lee and her team sought to understand the glymphatic-brain relationship in poor sleepers, which underlies memory decline. Dysfunction of the glymphatic system leads to the accumulation of toxic proteins, and this process has recently been implicated in several neurological disorders, such as Alzheimer’s disease, Parkinson’s disease and epilepsy.
“Sleep quality, brain activities, and glyphamtic functioning are related. Understanding how sleep quality influences the glymphatic system and human brain networks offers valuable insight into the neurophysiological mechanisms underpinning age-related memory change,” Professor Lee said.
The research team studied 72 older adults using functional MRI scans and sleep recordings. The findings indicate that poor sleep quality adversely affects normal brain function by deactivating the restorative glymphatic system.
“The results clearly reveal the effect of sleep on the human brain’s network through the glymphatic system, which in turn affects memory performance in older adults,” said Professor Lee.
“Therefore, maintaining efficient glymphatic functioning seems crucial for promoting healthy aging.”
The results of the study add important evidence that sleep quality affects cognitive health through the underlying neural relationships.
“Impaired memory is a common complaint among older adults with poor sleep quality,” Professor Lee noted.
“Our results provide a novel perspective on the interplay between sleep, the glymphatic system and multimodal brain networks.”
This study was recently published in Molecular Psychiatry in an article entitled “Effects of sleep on the glymphatic functioning and multimodal human brain network affecting memory in older adults”.
About this aging and sleep research news
Author: Jaymee Ng
Source: University of Hong Kong
Contact: Jaymee Ng – University of Hong Kong
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Effects of sleep on the glymphatic functioning and multimodal human brain network affecting memory in older adults” by Tatia M.C. Lee et al. Molecular Psychiatry
Abstract
Effects of sleep on the glymphatic functioning and multimodal human brain network affecting memory in older adults
Understanding how sleep affects the glymphatic system and human brain networks is crucial for elucidating the neurophysiological mechanism underpinning aging-related memory declines.
We analyzed a multimodal dataset collected through magnetic resonance imaging (MRI) and polysomnographic recording from 72 older adults. A proxy of the glymphatic functioning was obtained from the Diffusion Tensor Image Analysis along the Perivascular Space (DTI-ALPS) index.
Structural and functional brain networks were constructed based on MRI data, and coupling between the two networks (SC-FC coupling) was also calculated. Correlation analyses revealed that DTI-ALPS was negatively correlated with sleep quality measures [e.g., Pittsburgh Sleep Quality Index (PSQI) and apnea-hypopnea index].
Regarding human brain networks, DTI-ALPS was associated with the strength of both functional connectivity (FC) and structural connectivity (SC) involving regions such as the middle temporal gyrus and parahippocampal gyrus, as well as with the SC-FC coupling of rich-club connections.
Furthermore, we found that DTI-ALPS positively mediated the association between sleep quality and rich-club SC-FC coupling. The rich-club SC-FC coupling further mediated the association between DTI-ALPS and memory function in good sleepers but not in poor sleepers.
The results suggest a disrupted glymphatic-brain relationship in poor sleepers, which underlies memory decline.
Our findings add important evidence that sleep quality affects cognitive health through the underlying neural relationships and the interplay between the glymphatic system and multimodal brain networks.
