PI: Heidemann IBN: 9603640 Nerve cells, or neurons, are cells for which shape is critical for connections to distant targets. We understand very little about how the long structures, called neurites, are formed and become distinct for receiving information (a dendrite) or sending information (an axon). Recent studies have suggested that physical tension produced during development may have a role in determining the axonal or dendritic polarity as a cell elongates. This project, a collaboration between a biologist and a physicist, utilizes a novel technique of microscopically applying calibrated tension using fine glass needles on brain cells in culture, to characterize the cellular response to tension, the possible production of tension by parts of the neurite, and the crucial issue of whether tension can determine morphological polarity of the developing cell at a critical stage. Results from this innovative, multi-disciplinary collaboration could provide a potential breakthrough in understanding a key aspect of neuronal development, and be important beyond neuroscience to developmental biology and to cell biology.