Fig. 5. (A) Tetanus-induced augmentation in an A5 alpha lobe-extrinsic neuron. The neuron was identified by intracellular marking and categorized according to Rybak and Menzel (1993). The augmentation effect was very constant in three consecutive tetani, and the neuron returned to its initial sensitivity within 1 min. Therefore, the responses to test stimuli shortly before and after the three tetani were overlaid in the figure. (B) Spike trains of the neuron in A recorded at two intervals after the first tetanus (arrows). The stimulus artefacts mark the test pulses. (C) Augmentation of 11 PE1 neurons. The ordinates give the number of spikes elicited by a single stimulus (± S.D. C), and the abscissa time in s.