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. Author manuscript; available in PMC: 2014 Aug 18.
Published in final edited form as: Nat Neurosci. 2013 Aug 25;16(10):1409–1416. doi: 10.1038/nn.3496

Figure 4. Competition of the enlargement and shrinkage of neighboring spines.

Figure 4

(a) Spike timing protocol for the heterosynaptic competition of spine enlargement and shrinkage with 200 nM muscimol. Glutamate uncaging was applied 5 ms before the spike and 10 ms after the spike, and repetitive pairing was performed 80 times (5 Hz). (b) Fluorescence images of a dendrite subjected to the LTP (e) and LTD protocols (s). Scale bar, 2 μm. The soma was located to the right. (c) Volume changes in the spines shown in b subjected to the LTD protocol (s) and its neighbors (n) or to the LTP protocol (e) and its neighbors distal to spines with LTD stimuli (ne). The duration of glutamate uncaging in the LTP protocol was 3 ms. (d) Volume changes in spines subjected to the LTD protocol (14 spines, 14 dendrites, 14 slices, 13 rats) and their neighbors (34 spines, 14 dendrites, 14 slices, 13 rats) and to the LTP protocol (14 spines, 14 dendrites, 14 dendrites, 13 rats) and its distal neighbors (12 spines, 12 dendrites, 11 slices, 11 rats). The duration of glutamate uncaging in the LTP protocol was 1.8 ms (8 spines, 8 dendrites, 8 slices, 7 rats) or 3 ms (6 spines, 6 dendrites, 6 slices, 6 rats). (e) Peak amplitude changes in glutamate-induced currents (2pEPSCs) in spines subjected to the LTP protocol (5 spines, 5 dendrites, 5 slices, 5 rats), LTD protocol (5 spines, 5 dendrites, 5 slices, 5 rats), neighboring spines (6 spines, 5 dendrites, 5 slices, 5 rats) and distant ones (4 spines, 4 dendrites, 4 slices, 4 rats) ≥15 μm from stimulated ones. Glutamate-induced currents were recorded with voltage clamp at a holding potential of −65 mV. (f) Competition of spine enlargement against the spreading shrinkage induced by neighboring spine stimulation with the LTD protocol (muscimol, 200 nM or 50 nM; Supplementary Fig. 7a,b). Enlargement outcompeted shrinkage when spines were subjected to LTP protocols as in a with glutamate uncagings of 1.2 ms, 1.8 ms or 3 ms with 200 nM muscimol and 0.6 ms or 1.2 ms with 50 nM muscimol (Supplementary Fig. 7a,b). *P < 0.05, **P < 0.01 by Steel’s test versus 0 ms. The curves were drawn by eye. (g) The volume changes in spines subjected to the LTP protocol (5 spines, 5 dendrites, 5 slices, 3 rats, 3 ms), the LTD protocol and neighboring spines (23 spines, 5 dendrites, 5 slices, 3 rats) in the presence of dephosphorylated (dp)-cofilin peptide in the patch pipette and 200 nM muscimol. Data are presented as mean ± s.e.m.