A tiny brain region that governs alertness might hold the key to understanding the link between sleep and Alzheimer’s disease.
What your sleep can tell you about your risk of Alzheimer’s disease / © Credits
Changes in brain function related to sleep can occur long before the symptoms of neurodegenerative diseases appear. Scientists have identified a connection between the activity of a small brain area responsible for alertness and the rhythms of REM sleep, which is crucial for memory processes.
This was reported by Earth.com.
At the same time, scientists from the University of Liège emphasize that the results do not yet allow the use of sleep characteristics for diagnosing or predicting Alzheimer’s disease.
The study focused on the locus coeruleus, a tiny cluster of nerve cells in the brainstem. This area releases norepinephrine and is involved in regulating alertness, attention, and the transitions between sleep and wakefulness.
Scientists’ particular interest in the locus coeruleus stems from the fact that pathological changes in tau protein, characteristic of Alzheimer’s disease, can appear here in the early stages.
What the Sleep Study Revealed
The study involved 52 healthy individuals. 34 participants were between 18 and 31 years old, and another 18 were between 50 and 70 years old. Individuals with serious brain diseases, sleep disorders, or other conditions that could significantly affect the results were excluded from the experiment.
After a week of regular sleep patterns, participants spent a night in the laboratory. Using electroencephalography, scientists monitored brain activity, paying special attention to theta rhythm during REM sleep and sigma activity just before its onset.
The activity of the locus coeruleus was assessed separately during the day using functional MRI while volunteers performed two different perception and reaction tasks.
Researchers found that in both age groups, a certain type of stronger daytime response in the locus coeruleus was associated with more pronounced theta activity during REM sleep. A similar link was observed with sigma rhythm immediately before the start of this phase.
However, a different type of task yielded a different result: in older participants, a stronger response from this brain area was associated with less theta activity during REM sleep. No such clear connection was observed in younger volunteers.
Can Sleep Predict Alzheimer’s Disease?
According to the study’s authors, the results may suggest that a certain balance of activity in the system regulating alertness is important for normal REM sleep. However, the study only established a link between the indicators and did not prove that changes in the locus coeruleus directly affect sleep or memory.
Furthermore, the scientists did not investigate tau protein levels, genetic predisposition to Alzheimer’s disease, memory decline, or the future risk of developing the disease in the volunteers.
The study’s author, Gilles Vandewalle, suggests that in the future, sleep could become an accessible marker to help identify individuals with increased vulnerability even before obvious problems arise. However, this requires much larger and longer-term studies.
For now, the scientists’ conclusions are more cautious: the work of the small brain region controlling alertness is linked to certain REM sleep rhythms in healthy individuals. Whether these characteristics can be used for early detection of Alzheimer’s risk remains to be determined.
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