Distinguished Guest Lecturer
The Computational Magic of the Ventral Stream
Tomaso Poggio
CBCL, McGovern Institute
Massachusetts Institute of Technology
2012-05-10 3:30PM
E0024 Scott Lab
All interested parties are invited.
Refreshments will be served prior to the seminar.
Abstract:
I conjecture that the sample complexity of visual object recognition is mostly due to geometric image transformations and that a main goal of the ventral stream in visual cortex is to learn-and-discount image transformations. From this hypothesis and a few reasonable assumptions about neural mechanisms, I develop a theory predicting that the size of the receptive fields determines which transformations are learned during development; that the transformation represented in each area determines the tuning of the neurons in the area; and that class - specific transformations are learned and represented at the top of the ventral stream hierarchy. A surprising implication of these theoretical results is that the computational goals and some of the tuning properties of cells in the ventral stream may follow rather directly from symmetry properties (in the sense of physics and group theory) of the visual world through a process of unsupervised correlational learning, based on Hebbian synapses.
Bio: Tomaso Poggio is a computational neuroscientist whose recent work focuses on the processes by which the brain learns to recognize and categorize visual objects. His work is important not only towards understanding higher brain function, but also for the mathematical and computer applications of statistical learning.
Poggio is Eugene McDermott Professor in the Department of Brain and Cognitive Sciences and at the Artificial Intelligence Laboratory. He is also Co-Director of the Center for Biological and Computational Learning and was appointed Investigator immediately after the establishment of the McGovern Institute in 2000. He joined the MIT faculty in 1981, after ten years at the Max Planck Institute for Biology and Cybernetics in Tubingen, Germany. He received a Ph.D. in 1970 from the University of Genoa. Poggio is a Foreign Member of the Italian Academy of Sciences and a Fellow of the American Academy of Arts and Sciences.
Host: Mikhail Belkin
