Figure 7.

Whole-cell current-clamp recordings of bouton action potentials

(A) Spontaneous bouton action potential bursts (top) and expansion of an initial burst phase (bottom).

(B) Bouton action potential evoked upon incremental 0.3 ms current injections. Action potential amplitude and half-duration are indicated by arrows.

(C) Bouton action potentials evoked by incremental 100 ms current injections. Note that boutons typically fire a single action potential in response to long current injections.

(D) Example train of bouton action potentials (top: 90 × 0.3 ms current injections at 50 Hz, bottom: evoked action potential train). Box: Overlay of the first and last train action potential indicating stable action potential amplitude and action potential broadening upon high-frequency stimulation. Panel (B) was modified from Ritzau-Jost et al. (2021).¹