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Updated: Jul 4, 2026

Imaging Dendritic Spines in Caenorhabditis elegans
Published on: September 27, 2021
The spread of Ras activity triggered by activation of a single dendritic spine
Christopher D Harvey1, Ryohei Yasuda, Haining Zhong
1Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
Abstract:
In neurons, individual dendritic spines isolate N-methyl-d-aspartate (NMDA) receptor-mediated calcium ion (Ca2+) accumulations from the dendrite and other spines. However, the extent to which spines compartmentalize signaling events downstream of Ca2+ influx is not known. We combined two-photon fluorescence lifetime imaging with two-photon glutamate uncaging to image the activity of the small guanosine triphosphatase Ras after NMDA receptor activation at individual spines. Induction of long-term potentiation (LTP) triggered robust Ca2+-dependent Ras activation in single spines that decayed in approximately 5 minutes. Ras activity spread over approximately 10 micrometers of dendrite and invaded neighboring spines by diffusion. The spread of Ras-dependent signaling was necessary for the local regulation of the threshold for LTP induction. Thus, Ca2+-dependent synaptic signals can spread to couple multiple synapses on short stretches of dendrite.
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