Information processing by living systems
The Physics of Living Matter group in the Department of Physics and Astronomy at the University of Pennsylvania studies how organisms gather, process and respond to information. Much of our work focuses on computation and communication in the brain, but group members also work on cell signaling and regulatory networks. The group exploits theoretical and computational approaches from physics, statistics and computer science, and relies on experimental data gathered both within our lab and by collaborators at Penn and elsewhere.
Current experimental work in the group explores the adaptation of networks of neurons in the retina to stimulus statistics. Many of our physiological studies are based on multi-electrode array recordings. We have developed a simple, scalable and efficient new algorithm for sorting spikes recorded by such arrays.
Ongoing theoretical work concerns the organization of cortical maps (e.g. the place map in hippocampus, the orientation map in V1, and the "shape map" in Inferotemporal Cortex), and the application of Bayesian statistics to decision making in the brain. One goal of this work is understand the functional advantages conferred by the diversity of cell types and circuit architectures in the brain. We also apply information theory and techniques developed in neuroscience for data analysis and for understanding of network function, to analogous problems in the study of signaling and regulatory networks in cells. Recently, members of the lab have begun apply statistical techniques to understand the diversity of immune repertoire.
Both the theoretical and experimental effort are guided by the hypothesis that biological systems are adapted to the statistical structure of the stimuli that they encounter in their environments, subject to the constraints of biological computation This hypothesis can generate testable predictions if such statistical structure can be measured reliably.