Stress, Spines and New Memories

Rutgers University New Brunswick, New Brunswick NJ

Investigators

Abstract

Shors, Tracey 0217403 STRESS, SPINES & NEW MEMORIES Dendritic spines are tiny protrusions that exist by the tens of thousands on many excitatory neurons in the brain, including those in the hippocampal formation. Spines are potential sites of synapse formation and thus represent a means for neuronal integration. Based on their potential for conferring associations between neurons, it has been hypothesized that they are involved in the encoding of experience. Exposure to an acute stressful experience greatly increases the density of dendritic spines in the hippocampal formation of the male rat. This effect is robust and persistent - lasting at least 24 hrs after the event has ceased. The effect is also regionally specific in that it is evident on pyramidal neurons in area CA1 of the hippocampus but not in the somatosensory cortex. The primary goal of the proposed experiments is to identify the neuronal and hormonal mechanisms that are responsible for the experience-induced change in spine density. Specifically, experiments will be done to determine whether activation of the NMDA type of glutamate receptors is necessary for inducing the persistent increase in spine density. It will also be determined whether the presence of the major stress hormones, glucocorticoids, is necessary for the stress effects on synaptic anatomy. Although dendritic spines were identified over 100 years ago, their functional significance has remained elusive. The results from these studies should provide important insight into their functional significance and the mechanisms that mediate their plasticity.