Editors' ChoiceNeuroscience

Spreading the Word

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Science Signaling  08 Jul 2008:
Vol. 1, Issue 27, pp. ec248
DOI: 10.1126/scisignal.127ec248

Individual dendritic spines, the receiving ends of synapses, compartmentalize small diffusible molecules. In particular, Ca2+ signals in spines are synapse-specific. However, synapses interact in subtle ways through diffusible postsynaptic factors, which suggests the existence of molecular signals that are activated at individual synapses but that can spread to other synapses. Harvey et al. used 2-photon glutamate uncaging to induce long-term potentiation (LTP)--the electrophysiological correlate of memory--at single spines while imaging Ras activity using 2-photon fluorescence lifetime imaging. Ca2+-dependent Ras activation spread over ~10 micrometers of dendritic length and invaded nearby spines by diffusion. Neighboring synapses along a short stretch of dendrite may thus be coregulated due to this spread of signals downstream.

C. D. Harvey, R. Yasuda, H. Zhong, K. Svoboda, The spread of Ras activity triggered by activation of a single dendritic spine. Science 321, 136-140 (2008). [Abstract] [Full Text]