Visual Cortex Limits Pop-Out in the Superior Colliculus of Awake Mice

Cereb Cortex. 2017 Dec 1;27(12):5772-5783. doi: 10.1093/cercor/bhx254.


We detect objects more readily if they differ from their surroundings in motion, color, or texture. This increased saliency is thought to be related to increased responses in the visual cortex. The superior colliculus is another brain area involved in vision and especially in directing gaze and attention. In this study, we show that differences in texture orientation also increase responses in the superficial layers of the superior colliculus that receive retinal and cortical input. We found that gratings evoke more neural response when surrounded by orthogonal gratings than when surrounded by parallel gratings, particularly in the awake mouse. This pop-out is not originating from the visual cortex, and silencing visual cortex increased the relative difference in response. A model shows that this can result from retinotopically matched excitation from visual cortex to the superior colliculus. We suggest that the perceptual saliency of a stimulus differing from its surround in a low-level feature like grating orientation could depend on visual processing in the superior colliculus.

Keywords: corticotectal connections; surround suppression; vision.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • GABA-A Receptor Antagonists / pharmacology
  • Mice, Inbred C57BL
  • Microelectrodes
  • Models, Neurological
  • Muscimol / pharmacology
  • Photic Stimulation
  • Pupil / physiology
  • Receptors, GABA-A / metabolism
  • Retina / physiology
  • Superior Colliculi / physiology*
  • Visual Cortex / drug effects
  • Visual Cortex / physiology*
  • Visual Pathways / physiology
  • Visual Perception / physiology*
  • Wakefulness


  • GABA-A Receptor Antagonists
  • Receptors, GABA-A
  • Muscimol