Narrowband gamma oscillations propagate and synchronize throughout the mouse thalamocortical visual system

Summary

Rhythmic oscillations of neural activity permeate sensory systems. Studies in the visual system propose that broadband gamma oscillations (30 – 80 Hz) facilitate neuronal communication underlying visual perception. However, broadband gamma oscillations within and across visual areas show widely varying frequency and phase, providing constraints for synchronizing spike timing. Here, we analyzed data from the Allen Brain Observatory and performed new experiments that show narrowband gamma (NBG) oscillations (50 – 70 Hz) propagate and synchronize throughout the awake mouse thalamocortical visual system. Lateral geniculate (LGN) neurons fired with millisecond precision relative to NBG phase in primary visual cortex (V1) and multiple higher visual areas (HVAs). NBG in HVAs depended upon retinotopically aligned V1 activity, and neurons that fired at NBG frequencies showed enhanced functional connectivity within and across visual areas. Remarkably, LGN ON versus OFF neurons showed distinct and reliable spike timing relative to NBG oscillation phase across LGN, V1, and HVAs. Taken together, NBG oscillations may serve as a novel substrate for precise coordination of spike timing in functionally distinct subnetworks of neurons spanning multiple brain areas during awake vision.