Dirk M. Bucher
(Ph.D., Free University of Berlin, Germany, 2001)

Assistant Professor of Neuroscience

bucher@whitney.ufl.edu

Bucher Lab site

Plasticity and Homeostasis in Motor Systems

Our lab uses the central pattern generating networks (CPGs) found in the stomatogastric ganglion (STG) of lobsters and crabs to ask a series of questions concerning the regulation and variability of neuron and network properties and activity. CPGs are networks found in both vertebrate and invertebrate nervous systems that generate rhythmic activity for crucial behaviors like walking, swimming, and breathing. The STG contains only about 30 neurons and the connectivity is established, which makes it an ideal test bed for regulation of network output.

Homeostatic mechanisms have been investigated in a variety of systems at the level of intrinsic membrane properties and synaptic strengths in single neurons. However, ultimately, behavior depends on the performance of entire networks. We combine anatomical and imaging techniques, electrophysiology and biophysical measurements to investigate how tightly neuronal and synaptic properties need to be regulated to achieve functional network performance, and how such regulation can be achieved at the cellular and synaptic level.

Current Project

A neuron’s identity and function is determined by its morphology, the densities and spatial distribution of its specific types of receptors and ion channels, and its synaptic connections within the network. These features are all subject to dynamic regulation and must be matched to the functional requirements in the face of changing environmental and behavioral demands, both during growth and development, and in adult life. Homeostatic mechanisms are needed to ensure that dynamic changes occur only within certain boundaries that keep neuron and network activity in a functional range. We are only beginning to understand how nervous systems strike a balance between altering individual neurons and synapses in the name of plasticity, while maintaining long-term stability in neuronal system function. Our research focuses on the question of how stability of network function is achieved through regulation of neuronal properties, including morphology, synaptic and intrinsic membrane properties.

Personnel

Dirk M. Bucher, Assistant Professor, Department of Neuroscience
Alex W. Ballo, Laboratory Technician
Veronica Garcia, Research Technician

Selected Publications

Bucher, D. (in press). Central Pattern Generators. In: The New Encyclopedia of Neuroscience (Squire L, Albright T, Bloom F, Gage F, Spitzer N, eds). Amsterdam : Elsevier.

Marder, E., Bucher, D. (2007) Understanding circuit dynamics using the stomatogastric nervous system of lobsters and crabs. Ann Rev Physiol 69:291-316.

Bucher, D., Johnson, C.D., Marder, E. (2007) Neuronal morphology and neuropil structure in the stomatogastric ganglion of the lobster, Homarus americanus. J Comp Neurol 501(2):185-205.

Bucher, D., Taylor, A.L., and Marder, E. (2006; Epub, Feb. 22, 2006) Central pattern generating neurons simultaneously express fast and slow rhythmic activities in the stomatogastric ganglion. J Neurophysiol. 95:3617-3632.

Marder, E., Bucher, D., Schulz, D.J., and Taylor, A.L. (2005) Invertebrate central pattern generation moves along. Curr Biol 15: R685-699.

Marder, E. and Bucher, D. (2005) Robustness in Neuronal Systems: The Balance Between Homeostasis, Plasticity, and Modulation. In: Robust Design: A Repertoire of Biological, Ecological, and Engineering Case Studies., edited by E. J. New York: Oxford University Press.

Bucher, D., Prinz, A.A., and Marder, E. (2005) Animal-to-animal variability in motor pattern production in adults and during growth. J Neurosci 25: 1611-1619.

Pulver, S.R., Bucher, D., Simon, D.J., and Marder, E. (2005) Constant amplitude of postsynaptic responses for single presynaptic action potentials but not bursting input during growth of an identified neuromuscular junction in the lobster, Homarus americanus. J Neurobiol 62: 47-61.

Prinz, A.A., Bucher, D., and Marder, E. (2004) Similar network activity from disparate circuit parameters. Nat Neurosci 7: 1345-1352.

Büschges, A., Ludwar, B., Bucher, D., Schmidt, J., DiCaprio, R.A. (2004) Synaptic drive contributing to rhythmic activation of motoneurons in the deafferented stick insect walking system. Eur J Neurosci 19:1856-1862.

Bucher, D., Thirumalai, V., and Marder, E. (2003) Axonal dopamine receptors activate peripheral spike initiation in a stomatogastric motor neuron. J Neurosci 23: 6866-6875.

Bucher, D., Akay, T., DiCaprio, R.A., Buschges, A. (2003) Interjoint coordination in the stick insect leg-control system: the role of positional signaling. J Neurophysiol 89:1245-1255.

Marder, E. and Bucher, D. (2001) Central pattern generators and the control of rhythmic movements. Curr Biol 11: R 986-996.