File:Bourne Harris 2012 F4.png

Dramatic structural synaptic scaling revealed by ssEM following induction of LTP by TBS in the mature hippocampus. (a) EM and (ai) reconstruction of a small thin spine (category T, head diameter <0.45 mm). (b) EM and (bi) reconstruction of a medium thin spine (category T, head diameter >0.45 mm but <0.6 mm). (c) EM and (ci) reconstruction of a mushroom spine (M, head diameter >0.6 mm). (d) Small thin spines were significantly reduced in number (P < 0.05) while (e) PSDs on all remaining spines were significantly enlarged (**P < 0.01; *P < 0.05). (f) Reconstructions of control and LTP dendrites demonstrate equal summed PSD area per micron length of dendrite, despite large differences in their average synapse size and density. Scale cube = 0.5 mm on a side. (g) Average summed PSD area per micron length of dendrite is the same for dendrites across all times in the control and TBS-LTP conditions.Adapted from Bourne and Harris [4].