Ralph Freeman

Professor (Vision Science)

Email: freeman@neurovision.berkeley.edu

Research areas: Systems and Computational Neuroscience

Of all the sensory systems, vision is arguably the most important. Our research is concerned with the organization of central visual pathways in the brain. We use a systems approach to study local neural circuits and to address questions on how information is encoded, transmitted and detected. We seek to determine the neural basis of specific visual phenomena and aspects of visual performance. We are also interested in the development and plasticity of vision. What is genetically determined and what is shaped by the early visual environment. In general, we attempt to construct physiologically plausible models or hypotheses whose predictions are subject to experimental verification. Our experiments are usually designed to test the predictions of the models. Neurophysiological approaches are used to carry out experiments in which single neurons or groups of cells are studied. Cross-correlation analysis is used to determine functional interconnections between neurons. Recently, we have pursued questions concerning the relationships between neural and metabolic functions in the cerebral cortex. This area has direct applications to non-invasive imaging approaches such as fMRI.

Selected Publications

Thompson, J.K., Peterson, M., and Freeman, R.D. 2004. High resolution neurometabolic coupling revealed by focal activation of visual neurons Nature Neuroscience 7: 919-920.

Peterson, M., Li, B., and Freeman, R.D. 2004. The Derivation of Direction Selectivity in the Striate Cortex Journal of Neuroscience 24: 3583-3591.

Freeman, R.D. 2003. Cortical Columns: A multi-parameter examination Cerebral Cortex 13: 70-72.

Thompson, J.K., Peterson, M., Freeman, R.D. 2003. Single neuron activity and tissue oxygenation in the cerebral cortex Science 299: 1070-1072.

Li, B., Peterson, M., Thompson, J.K., Duong, T., and Freeman, R.D. 2005. Cross-orientation suppression: monoptic and dichoptic mechanisms are different Journal of Neurophysiology 94: 1645-1650.