Resting-state functional connectivity between the locus coeruleus and the left caudal temporal thalamus was correlated with attention performance and attention decline after acute sleep deprivation, suggesting a potential LC-thalamus-attention mechanism associated with sleep loss.
Key Findings
Results
Functional connectivity between the locus coeruleus and the left caudal temporal thalamus significantly increased after acute sleep deprivation.
Thirty healthy participants with normal sleep patterns underwent resting-state fMRI before and after acute sleep deprivation.
The psychomotor vigilance task (PVT) was used to assess attention performance.
The increase in LC-thalamus FC was specifically localized to the left caudal temporal thalamus.
This finding was observed using resting-state functional magnetic resonance imaging (fMRI).
Results
LC-thalamus functional connectivity during rested wakefulness was correlated with both attention performance and attention decline after acute sleep deprivation.
Baseline (rested wakefulness) LC-thalamus FC predicted subsequent attention decline following sleep deprivation.
The associations were measured between LC-left caudal temporal thalamus FC and PVT-derived attention metrics.
These correlations suggest that individual differences in LC-thalamus connectivity at baseline may predispose individuals to differential vulnerability to sleep loss.
The study involved 30 healthy participants with normal sleep patterns.
Results
The LC-thalamus-attention associations were primarily observed when global signal regression (GSR) was applied during preprocessing.
Sensitivity analyses indicated that the observed relationships between LC-thalamus FC and attention were dependent on the preprocessing choice of GSR.
Similar effects were also observed in other thalamic subregions beyond the left caudal temporal thalamus.
The dependence on GSR indicates that the analytical preprocessing pipeline is a critical methodological consideration for interpreting these results.
The authors note this as a limitation affecting the robustness and generalizability of the findings.
Results
LC-derived functional connectivity patterns were spatially associated with the distribution of the norepinephrine transporter.
Norepinephrine transporter (NET) distribution data were obtained from a public dataset.
The spatial correspondence between LC FC patterns and NET distribution supports the neurochemical specificity of the LC-based FC analysis.
This association suggests that the observed FC patterns reflect noradrenergic pathways originating from the LC.
This validation approach helps confirm that the LC seed region was accurately identified and functionally characterized.
Discussion
The authors describe their findings as pilot results providing a testable framework for future studies with optimized LC imaging and analytical approaches.
The study sample was limited to 30 healthy participants, which the authors characterize as a pilot study.
The authors note the need for optimized LC imaging given the small size and brainstem location of the LC.
The dependence of findings on GSR preprocessing is highlighted as a key analytical challenge requiring further investigation.
The authors propose a LC-thalamus-attention mechanism as a framework rather than a definitive conclusion.
What This Means
This research suggests that a small brain region called the locus coeruleus (LC) — which produces the alertness-related chemical norepinephrine — may play an important role in how sleep deprivation impairs attention. The study had 30 healthy adults undergo brain scans and attention testing both before and after a night of total sleep deprivation. Researchers found that the communication (functional connectivity) between the LC and a part of the thalamus (a brain relay center) increased after sleep loss, and that how strongly these two regions communicated before sleep deprivation could predict how much a person's attention would decline afterward.
An important caveat is that these findings depended heavily on a specific step in how the brain scan data were processed, called global signal regression. When this step was not applied, the associations largely disappeared, which means the results should be interpreted with caution. The researchers also confirmed that the brain connectivity patterns they measured aligned with the known distribution of norepinephrine-related proteins in the brain, lending biological plausibility to their findings.
This research suggests there may be a biological 'LC-thalamus-attention' pathway that contributes to why some people are more vulnerable to the cognitive effects of sleep loss than others. However, because this was a small pilot study and the results were sensitive to how the data were analyzed, the authors stress that larger studies with better imaging techniques are needed before firm conclusions can be drawn.
Ai M, Wu K, Song M, Huo B, Wu Z, Jia H, et al.. (2026). The role of resting-state functional connectivity of locus coeruleus in attention decline after acute sleep deprivation.. Sleep medicine. https://doi.org/10.1016/j.sleep.2026.108769