Mathematical Biology Seminar Sharon Crook, Arizona State University Wednesday April 16, 2008 3:05pm in LCB 225 "Modeling activity-dependent changes in dendritic spine structure" Abstract: Recent evidence indicates that the morphology and density of dendritic spines are regulated during synaptic plasticity. High-frequency stimuli that induce long-term potentiation have been associated with increases in the number and size of spines. In contrast, low-frequency stimuli that induce long-term depression are associated with decreases in the number and size of spines. Decreases in spine density also occur due to excitotoxicity associated with very high levels of activity such as during seizures. This activity-dependent structural plasticity exists over a vast range of time scales, from minutes to days or weeks. In this work, developed in collaboration with Steve Baer, we extend previous modeling studies to include calcium-mediated spine restructuring. The models are based on the standard dimensionless cable equation for the changes in membrane potential in a passive dendrite. Additional equations characterize the activity-dependent changes in spine shape along the dendrite. We use computational studies to investigate the interactions between the many activity-dependent spines and to reveal the impact of their collective dynamics on the output properties of the dendrite.