[Abstract Title]. - Society for Neuroscience

Oxidation-state-dependent interconnections between spines were visible at the dendritic
terminals in the cortex (8 ± 5.6; n = 113 clusters). In the CA3 region of the hippocampus, these
clusters were very large (482 ± 106; n = 106 clusters). These interconnections due to oxidationstate
dependent progression of chemical reaction between the dendritic spines open possibilities
to examine similar oxygenation-state-dependent transient functional connections between the
dendritic spines of adjacent neurons at sites of increased signal intensity seen in fMRI both
during learning and memory retrieval.
Disclosures: K.I. Vadakkan, None.
Poster
239. Structural Plasticity at Synapses I
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 239.20/E17
Topic: B.08.i. Structural plasticity
Support: The DANA Foundation
Title: Ephrin-A2 is required for stabilization of dendritic spines in the developing mouse
somatosensory cortex
Authors: X. YU, T. XU, V. T. CHEW, *Y. ZUO;
Mol. Cell and Devel Biol, UC Santa Cruz, Santa Cruz, CA
Abstract: Tyrosine kinase EphAs and their ligand ephrin-As play important roles in axon
guidance and topographic map formation during brain development. However, their roles in
synapse formation and activity-dependent plasticity remain unclear. Using transcranial twophoton
microscopy, we repeatedly imaged postsynaptic dendritic spines in barrel cortex of
transgenic mice expressing Yellow Fluorescent Protein. Here we show that adolescent ephrin-A2
knockout (KO) mice have significantly higher (>40%) spine elimination over short periods of
time (2, 4 and 8 days) than littermate controls (P