title: Superior colliculus neurons encode a visual saliency map during free viewing of natural dynamic video.
abstract: Models of visual attention postulate the existence of a saliency map whose function is to guide attention and gaze to the most conspicuous regions in a visual scene. Although cortical representations of saliency have been reported, there is mounting evidence for a subcortical saliency mechanism, which pre-dates the evolution of neocortex. Here, we conduct a strong test of the saliency hypothesis by comparing the output of a well-established computational saliency model with the activation of neurons in the primate superior colliculus (SC), a midbrain structure associated with attention and gaze, while monkeys watched video of natural scenes. We find that the activity of SC superficial visual-layer neurons (SCs), specifically, is well-predicted by the model. This saliency representation is unlikely to be inherited from fronto-parietal cortices, which do not project to SCs, but may be computed in SCs and relayed to other areas via tectothalamic pathways.
authors.affiliation: Centre for Neuroscience Studies, Queen's University, 18 Stuart St, Kingston, Ontario, Canada K7L3N6.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: White
authors.affiliation: IBM Research, Almaden, 650 Harry Road, San Jose, California 95120, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Berg
authors.affiliation: Centre for Neuroscience Studies, Queen's University, 18 Stuart St, Kingston, Ontario, Canada K7L3N6.
authors.forename: Janis Y
authors.initials: JY
authors.lastname: Kan
authors.affiliation: Centre for Neuroscience Studies, Queen's University, 18 Stuart St, Kingston, Ontario, Canada K7L3N6.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Marino
authors.affiliation: Department of Computer Science, University of Southern California, 0781, 941 Bloom Walk, Los Angeles, California 90089, USA.
authors.forename: Laurent
authors.initials: L
authors.lastname: Itti
authors.affiliation: Centre for Neuroscience Studies, Queen's University, 18 Stuart St, Kingston, Ontario, Canada K7L3N6.
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Munoz
mesh_terms: D000818:Animals; D001288:Attention / Q000502:physiology*; D003198:Computer Simulation; D008253:Macaca mulatta; D008297:Male; D023421:Models, Animal; D008959:Models, Neurological; D009434:Neural Pathways; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D012438:Saccades; D012984:Software; D013477:Superior Colliculi / Q000166:cytology / Q000502:physiology*; D013788:Thalamus / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*