Lead
The brain does not stop tracking where the eyes are looking just because the eyelids are shut. A team of neuroscientists at Vrije Universiteit Amsterdam has shown that gaze-related activity persists throughout the cerebral cortex and cerebellum even when participants close their eyes and, remarkably, continues during sleep. The finding challenges a long-held assumption in resting-state fMRI research that the signals picked up from a motionless person with closed eyes are essentially free of eye-movement contamination, and it suggests that gaze could serve as a hidden behavioral dimension coloring much of what we think we know about the brain’s intrinsic activity.
The study, posted July 16 on bioRxiv as a preprint that has not yet undergone peer review, used a refined MR-based eye-tracking technique to reconstruct gaze behavior from fMRI data while participants lay still with their eyes closed, both while awake and while asleep. The results reveal a degree of gaze-brain coupling that is larger and more widespread than previously suspected, spanning sensory, motor, and association regions alike.
What they found
Zachary Nudelman and Matthias Nau used a scalable eye-tracking method that infers gaze direction from the same fMRI signals routinely collected during resting-state scans. Because the eyes act as moving dipoles in the static magnetic field of an MRI scanner, their orientation shifts create measurable perturbations in the raw data. The researchers extracted these gaze proxy signals and correlated them with BOLD (blood-oxygen-level-dependent) activity across the whole brain.
The coupling was widespread. Gaze-related activity appeared not only in classical visual areas of the occipital lobe but also in the frontal eye fields, parietal cortex, somatosensory regions, motor cortex, cingulate gyrus, and large swaths of the cerebellum, an anatomical distribution far exceeding what is typically attributed to oculomotor control. The cerebellum, in particular, showed robust gaze-dependent signals, consistent with its role in coordinating fine motor output including eye movements.
Crucially, these patterns largely persisted when participants fell asleep. While the strength of coupling did shift in certain regions (some areas showed slightly reduced gaze-brain correlation during sleep, others remained stable), the overall architecture of gaze-dependent activity remained intact. The brain continued to show organized activity tied to the inferred position of the eyes even in the absence of visual input or conscious awareness.
The gaze signals also mattered for how connectivity between brain regions is measured. When the researchers computed standard resting-state functional connectivity (the correlation of BOLD activity between pairs of brain regions), they found that controlling for gaze systematically altered the results. Functional connectivity estimates shifted when gaze was accounted for, in some cases substantially, indicating that eye-movement artifacts are not randomly distributed noise but structured signals that can masquerade as neural connectivity.
Why it matters
Resting-state fMRI is one of the most widely used tools in human neuroscience. Researchers scan participants who lie still with their eyes closed and interpret the resulting BOLD fluctuations as the brain’s intrinsic functional architecture (the default mode network, the salience network, the frontoparietal control networks, and so on). The assumption baked into thousands of published studies is that eyes-closed rest yields a relatively pure measure of these networks, uncontaminated by the large visual and oculomotor transients that occur when eyes are open and moving.
This study undermines that assumption. If gaze-related signals are pervasive during eyes-closed rest and sleep, then a portion of what resting-state fMRI captures is not purely neural but reflects the brain processing where the eyes are pointing, even in darkness and even during unconsciousness. For studies of consciousness itself (which often rely on comparing brain activity in wakeful rest, sleep, and disorders of consciousness), failing to account for this hidden gaze dimension could confound results.
The findings also open a new door. If eye-brain dynamics remain organized during sleep, gaze tracking could become a window into states of consciousness that are otherwise opaque. Clinicians might one day infer a patient’s level of awareness from gaze-related brain signatures, or researchers might use gaze proxies to track the depth of sleep or anesthesia without disturbing the sleeper.
Limits
As a preprint, this work has not been independently verified by peer review. The gaze reconstruction method, while clever, is indirect: it infers eye position from field perturbations rather than measuring eye movements directly. Validation against concurrent electrooculography or video-based eye tracking in the dark would strengthen the approach.
The sleep data come from a nap paradigm, not a full overnight sleep study, and it remains unclear whether the gaze-brain coupling observed during light sleep extends to deeper NREM stages or to REM sleep, where rapid eye movements are a defining feature. The sample size is modest, and individual variability in gaze patterns during rest is not yet well characterized. Finally, because the gaze signal is extracted from the same BOLD data used to compute connectivity, the risk of circular analysis (removing shared variance that is partly neural) requires careful statistical controls that the authors acknowledge.
Bottom line
Where the eyes go, the brain follows, even when the eyes are closed and the person is asleep. This study shows that gaze-dependent activity is a widespread and structured feature of fMRI signals during eyes-closed rest, one that bleeds into functional connectivity estimates and persists across states of consciousness. The results argue for a reexamination of resting-state methods and suggest that what we have been calling intrinsic brain activity may be, in part, a conversation between the brain and its own hidden gaze dynamics.
Source
Nudelman, Z., & Nau, M. (2026). Brain-wide gaze-dependent activity during eyes-closed rest and sleep. bioRxiv. https://doi.org/10.64898/2026.07.10.737751 (preprint, not yet peer-reviewed).