Changes in formation and elimination of axonal boutons during neuropathic pain. (A) Long-term time-lapse image of the same axonal segments before and after PSL injury. Arrowheads indicate boutons generated (red) or eliminated (blue) when compared with the previous imaging session. Scale bar, 5 μm. (B) Gain and loss rates of the sham control mice show little change over the 2-week imaging period. (C) Gain and loss rates of the neuropathic mice show moderate increase and decrease only during the first 3 days after PSL (*P < 0.05 vs. loss, paired t-test). Sham control: n = 10 mice (367 boutons); PSL: n = 6 mice (167 boutons).