# Henry Greenside

## Professor of Physics

### Overview

After working in nonlinear dynamics and nonequilibrium pattern formation for many years, my research group has begun studying problems in theoretical neurobiology in collaboration with Professor Richard Mooney's experimental group on birdsong at Duke University. The main scientific question we are interested in is how songbirds learn to sing their song, which is a leading experimental paradigm for the broader neurobiology question of how animals learn behaviors that involve sequences of time. My group is interested in problems arising at the cellular and network levels (as opposed to behavioral levels). One example is understanding the origin, mechanism, and eventually the purpose of highly sparse high-frequency bursts of spikes that are observed in the nucleus HVC of songbird brains (this is the first place where auditory information seems to be combined with motor information). A second example is to understand how auditory and motor information are combined, e.g., there are data that suggests that the same group of neurons that instruct the respiratory and syringeal muscles to produce song (again in nucleus HVC) are also involved in recognizing song. A third example is trying to understand changes in anatomy (increases in spine stability) that were recently observed in living brain tissue as a bird learns its song.

O'Hern, CS, Egolf, DA, and Greenside, HS. "Lyapunov spectral analysis of a nonequilibrium Ising-like transition." *Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics* 53.4 SUPPL. A (1996): 3374-3386.

Egolf, DA, and Greenside, HS. "Characterization of the transition from defect to phase turbulence." *Physical Review Letters* 74.10 (1995): 1751-1754.

Egolf, DA, and Greenside, HS. "Spatial variation of correlation times for 1D phase turbulence." *Physics Letters A* 185.4 (1994): 395-400.
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Egolf, DA, and Greenside, HS. "Relation between fractal dimension and spatial correlation length for extensive chaos." *Nature* 369.6476 (1994): 129-131.

Bayly, PV, Johnson, EE, Wolf, PD, Greenside, HS, Smith, WM, and Ideker, RE. "A quantitative measurement of spatial order in ventricular fibrillation." *J Cardiovasc Electrophysiol* 4.5 (October 1993): 533-546.

Egolf, DA, and Greenside, HS. "Stochastic to deterministic crossover of fractal dimensions for a Langevin equation." *Physical Review E* 47.5 (1993): 3753-3756.
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Greenside, HS. "Recent advances in chaos theory." *International Conference on Fuzzy Theory and Technology Proceedings, Abstracts and Summaries* (1992): 14--.

Greis, NP, and Greenside, HS. "Implication of a power-law power-spectrum for self-affinity." *Physical Review A* 44.4 (1991): 2324-2334.
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Reiman, AH, and Greenside, HS. "Computation of zero β three-dimensional equilibria with magnetic islands." *Journal of Computational Physics* 87.2 (1990): 349-365.
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Greenside, HS. "Comments on a recent paper by W. Zijl." *International Journal for Numerical Methods in Fluids* 9.10 (October 1989): 1302-1304.
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