Neuronal mechanisms underlying visual object recognition

The long-term goal of our research is an understanding of the neuronal computations that support the brain's remarkable ability to recognize visual objects. The key computational challenge of object recognition is the extraction of object identity irrespective of visual clutter, object position, size, pose and illumination. Our working hypothesis is that a series of brain processing stages gradually transform pixel-based images of the world into patterns of neuronal activity that emphasize object identity and discount object position, size, view, and illumination. Several lines of evidence suggest that these high level neuronal representations are conveyed by neuronal responses in a cortical region called the inferotemporal cortex (IT). For instance, IT lesions can disrupt object recognition, and some IT neurons have the remarkable property of strong selectivity for complex objects (e.g. faces and other shapes) and relative invariance to object position and size. Thus, our current studies are focused on understanding the IT neuronal representation, how it is produced, and its role in object recognition. Our primary experimental tool is single and multi-neuron recording in awake, non-human primates, engaged in recognition tasks. We also employ psychophysical techniques so that neuronal responses can be directly correlated with the animal's behavior, and compared with that of humans. We interact closely with theoretical neuroscientists exploring computational models of recognition and cognitive neuroscientists studying homologous areas of the human brain to both guide our experiments and to test ideas suggested by the experimental data. We hope that our studies of the brain's object representations will contribute to a deep understanding of the neuronal mechanisms that underlie memory and cognition, will enable the creation of artificial vision systems and visual prostheses, and will assist in the development of molecular and behavioral techniques to aid those suffering from learning and memory disabilities.