Abstract
Detection of salient objects in the visual scene is a vital aspect of an animal's interactions with its environment. Here, we show that neurons in the mouse superior colliculus (SC) encode visual saliency by detecting motion contrast between stimulus center and surround. Excitatory neurons in the most superficial lamina of the SC are contextually modulated, monotonically increasing their response from suppression by the same-direction surround to maximal potentiation by an oppositely-moving surround. The degree of this potentiation declines with depth in the SC. Inhibitory neurons are suppressed by any surround at all depths. These response modulations in both neuronal populations are much more prominent to direction contrast than to phase, temporal frequency, or static orientation contrast, suggesting feature-specific saliency encoding in the mouse SC. Together, our findings provide evidence supporting locally generated feature representations in the SC, and lay the foundations towards a mechanistic and evolutionary understanding of their emergence.
Highlights
The detection of objects in the environment is crucial for an animal’s ability to efficiently and safely navigate the world
We imaged the most superficial lamina of the stratum griseum superficiale (SGS), which we have recently shown to be enriched with neurons that are highly selective for movement direction (Inayat et al, 2015)
We uncoupled the movement direction between the stimulus center and surround, and determined how superficial SGS (sSGS) responses were modulated by this form of motion contrast (Figure 1C)
Summary
The detection of objects in the environment is crucial for an animal’s ability to efficiently and safely navigate the world. Objects are processed by neurons that respond to specific features in their receptive fields (RFs), such as orientation, movement direction, luminance, and color. Each RF provides a local representation of the visual scene. A vertical bar would ‘pop out’ perceptually when it is surrounded by horizontal bars, but not among other identical vertical bars (Li, 1999). Such saliency computation requires a comparison between local and global visual features at the neuronal level
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
