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. Dr. Itti and his team recently conducted 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. They found 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. Further, they compared saliency coding in neurons in the primary visual cortex (V1) and the SC. They found that while visual latency was often the same or earlier for V1 neurons than SC superficial visual layer neurons (SCs), the saliency representation emerged earlier in SCs than in V1. Because the dominant input to the SCs arises from V1, these relative timings are consistent with the hypothesis that SCs neurons pool the inputs from multiple V1 neurons to form a feature-agnostic saliency map, which may then be relayed to other brain areas.

Laurent Itti received his MS degree in Image Processing from the Ecole Nationale Superieure des Telecommunications (Paris, France) in 1994, and his PhD in Computation and Neural Systems from Caltech (Pasadena, California) in 2000. He has since then been an Assistant, Associate, and now Full Professor of Computer Science, Psychology, and Neuroscience at the University of Southern California. Dr. Itti's research interests are in biologically-inspired computational vision, in particular in the domains of visual attention, scene understanding, control of eye movements, and surprise. This basic research has technological applications to, among others, video compression, target detection, and robotics. Dr. Itti has co-authored over 150 publications in peer-reviewed journals, books and conferences, three patents, and several open-source neuromorphic vision software toolkits.

Faculty Host: Vincent Ferrera, PhD, Professor of Neuroscience (in Psychiatry); Principal Investigator at Columbia's Zuckerman Institute

For questions about the lecture, please contact [email protected].

Those who wish to meet the speaker during the visit should contact Fabian Silva Munoz.

This seminar is part of the Systems, Cognitive and Computational Neuroscience Seminar Series at Columbia's Zuckerman Institute, which focuses on cognition and decision making research. Internationally renowned speakers present their recent work on these topics using behavioral, neurobiological and computational approaches. Seminars take place approximately every other week on Tuesdays at 4 pm in the Jerome L. Greene Science Center (9th floor).