TITLE:

MODELING ACTIVITY-DEPENDENT SYNAPSE RESTRUCTURING (No. 29)

DATE:

Friday, November 21st, 2003

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Diana W. Verzi, Department of Mathematics, San Diego State University-Imperial Valley Campus

ABSTRACT:

The spread of electrical activity in a dendritic tree is shaped, in part, by its morphology. Conversely, experimental evidence is growing that electrical and chemical activity can slowly shape the morphology of the dendrite. In this theoretical study, the dendritic spines are dynamic elements, with biophysical properties that change in response to patterns of chemical and/or electrical activity. Recent experiments and diagrammatic models suggest that activity-dependent processes can regulate structural modifications in

dendritic spines as well as their distribution along the dendrite. The study considers how local changes in spine structure (minutes to hours) can influence patterns of electrical activity along the dendrite; and how electrical activity due to synaptic events and excitable membrane dynamics can, over time, influence the morphology of the dendrite.

The model presents a slow subsystem for structural synaptic plasticity associated with long-term potentiation (LTP). A perturbation problem evolves naturally when the spine stem shortens since the ratio of spine stem resistance to input resistance is then small and the difference between spine head and dendritic potentials become negligible. An asymptotic expansion of head potential in terms of dendritic potential leads to a reduced model for post-synaptic restructuring that captures the dynamics of the full model in a briefer computational period when the spines are well connected to the dendrite.

HOST:

Antonio Palacios

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