Spine neck plasticity regulates compartmentalization of synapses
Nature Neuroscience - 2014 May;17(5):678-85
Jan Tønnesen, Gergely Katona, Balázs Rózsa, U Valentin Nägerl
The team of Valentin Nägerl at the University of Bordeaux has discovered a novel structural mechanism by which neurons can rapidly tune their synapses in response to stimulation.
Dendritic spines have been proposed to transform synaptic signals through chemical and electrical compartmentalization. However, the quantitative contribution of spine morphology to synapse compartmentalization and its dynamic regulation are still poorly understood.
We used time-lapse superresolution STED imaging in combination with FRAP measurements, 2-photon glutamate uncaging, electrophysiology and simulations to investigate the dynamic link between nanoscale anatomy and compartmentalization in live spines of CA1 neurons in mouse brain slices.
We report a diversity of spine morphologies that argues against common categorization schemes, and establish a close link between compartmentalization and spine morphology, where spine neck width is the most critical morphological parameter. We demonstrate that spine necks are plastic structures that become wider and shorter after LTP. These morphological changes are predicted to lead to a substantial drop in spine head EPSP, while leaving overall biochemical compartmentalization preserved.
STED image of dendritic spines (left), scale bar 500 nm; concurrent FRAP experiment to measure diffusional coupling between spines and dendrite (right).
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