Year: 2025
Type: preprint
Abstract: The day-night cycle drives profound environmental changes, which animals anticipate using the circadian clock. The clock synchronizes with this cycle by extracting features of light that indicate solar elevation. It uses a specialized dynamic range to sense relevant photon rates and precise, extended temporal integration to encode total photon counts. This feature selectivity is distinct from that of visual perception and is thought to arise in the brain. We have found it within the retina’s M1 melanopsin photoreceptors, which signal light to the clock. M1s have heterogeneous intrinsic and synaptic drives, and collectively account for the dynamic range of circadian photoregulation. Both individually and as a population, M1s approach the level of temporal integration observed behaviorally. M1s and behavior match closely when the pupillary light reflex, another M1-driven function, dynamically shapes retinal illumination. Thus, the earliest steps of photoreception are tuned to signifiers of Earth’s rotation.
Authors: Elliott S. Milner, Hannah A. Blume, Navid Mousavi, Michael C. Brown, Franklin Caval-Holme, Nguyen-Minh Viet, Takeharu Nagai, Michael Tri H. Do
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
Awards: G1929716843, G2436317640, Subcellular Origins of Extensive Spatial Integration by Ganglion Cell Photoreceptors, Physiological Mechanisms of Intensity Encoding in Ganglion Cell Photoreceptors, G3384271232, Origins and Transformations of Signals for Circadian Regulation, Boston Intellectual and Developmental Disabilities Research Center, G5948587712, Neurophysiology of Melanopsin Photoreceptors, G7523027036, G7789912157, Properties and Mechanisms of Melanopsin Photoreception, Transformations of photic information in melanopsin pathways, Signal Generation and Processing in the Retinohypothalamic Pathway, Downstream Actions of Biophysical Mechanisms in the Visual System, CORE GRANT FOR VISION RESEARCH, Intrinsically photosensitive retinal ganglion cells and their central projections
OpenAlex ID: W7117766745