Coordination of distinct sources of excitatory inputs enhances motion selectivity in the mouse visual thalamus

Abstract

Multiple sources innervate the visual thalamus to influence image-forming vision prior to the cortex, yet it remains unclear how non-retinal and retinal input coordinate to shape thalamic visual selectivity. Using dual-color two-photon calcium imaging in the thalamus of awake mice, we observed similar coarse-scale retinotopic organization between axons of superior colliculus neurons and retinal ganglion cells, both providing strong converging excitatory input to thalamic neurons. At a fine scale of [~]10 {micro}m, collicular boutons often shared visual feature preferences with nearby retinal boutons. Inhibiting collicular input significantly suppressed visual responses in thalamic neurons and specifically reduced motion selectivity in neurons preferring nasal-to-temporal motion. The reduction in motion selectivity could be the result of silencing sharply tuned direction-selective colliculogeniculate input. These findings suggest that the thalamus is not merely a relay but selectively integrates inputs from multiple regions to build stimulus selectivity and shape the information transmitted to the cortex. HIGHLIGHTSChronic dual-color calcium imaging reveals diverse visual tuning of collicular axonal boutons. Nearby collicular and retinal boutons often share feature preferences at [~]10 {micro}m scale Silencing of collicular input suppresses visual responses in the majority of thalamic neurons. Silencing of collicular input reduces motion selectivity in thalamic neurons.