title: Thalamus provides layer 4 of primary visual cortex with orientation- and direction-tuned inputs.
abstract: Understanding the functions of a brain region requires knowing the neural representations of its myriad inputs, local neurons and outputs. Primary visual cortex (V1) has long been thought to compute visual orientation from untuned thalamic inputs, but very few thalamic inputs have been measured in any mammal. We determined the response properties of ∼ 28,000 thalamic boutons and ∼ 4,000 cortical neurons in layers 1-5 of awake mouse V1. Using adaptive optics that allows accurate measurement of bouton activity deep in cortex, we found that around half of the boutons in the main thalamorecipient L4 carried orientation-tuned information and that their orientation and direction biases were also dominant in the L4 neuron population, suggesting that these neurons may inherit their selectivity from tuned thalamic inputs. Cortical neurons in all layers exhibited sharper tuning than thalamic boutons and a greater diversity of preferred orientations. Our results provide data-rich constraints for refining mechanistic models of cortical computation.
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA.
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Sun
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA.
authors.forename: Zhongchao
authors.initials: Z
authors.lastname: Tan
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA.
authors.forename: Brett D
authors.initials: BD
authors.lastname: Mensh
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA.
authors.forename: Na
authors.initials: N
authors.lastname: Ji
mesh_terms: D000465:Algorithms; D000818:Animals; D001931:Brain Mapping; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D009415:Nerve Net / Q000502:physiology; D059906:Neuroimaging; D009474:Neurons / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation; D017729:Presynaptic Terminals / Q000502:physiology; D013788:Thalamus / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology