Year: 2026
Type: preprint
Abstract: Light shapes mammalian physiology and behaviour through hypothalamic pathways, yet how these pathways process visual information in day-active species remains poorly understood. Based largely on work in nocturnal rodents, the suprachiasmatic nucleus (SCN) is classically viewed as a retinal target that encodes ambient illumination for circadian entrainment. We combine anatomical tracing, light-evoked c-Fos mapping and high-density silicon-probe electrophysiology to define visual processing in the suprachiasmatic region of the diurnal murid Rhabdomys pumilio . We find that retinal input and light-evoked activity extend beyond the SCN into rostral and lateral peri-SCN hypothalamus. Within the SCN, neurons encode irradiance with graded changes in maintained firing broadly similar to those observed in parallel recordings of nocturnal Mus domesticus . Across the wider suprachiasmatic region, Rhabdomys neurons show selectivity for more dynamic visual stimuli, including luminance transitions, contrast and temporal structure. Unsupervised clustering identifies five functionally distinct hypothalamic visual response classes with different anatomical distributions. These findings reveal an expanded hypothalamic visual network in a diurnal mammal, placing SCN irradiance coding within a broader system for processing dynamic visual features.
Institution: University of Manchester
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
Awards: Seeing into the future: Proactive adjustments of visual coding by the circadian clock, MELANOPSIN CONTRIBUTION TO PATTERNS DISCIRMINATION IN DIURNAL AND NOCTURNAL RODENTS, Trade Preferences as Development Aid: Theory and Evidence, Daylight vision beyond cone photoreceptors, G4434982853, Out of the dark, how daytime light influences sleep and supports circadian rhythms, Daylight vision beyond cone photoreceptors, G6403752324, G7092465196, Action in Vision, Seeing into the future: Proactive adjustments of visual coding by the circadian clock, Action in Vision
OpenAlex ID: W7212904148