Figure 2. Adaptation of neuronal intrinsic excitability.

A, Characteristic neuronal response to intracellular current injection at varying frequencies. Ten pulses were injected during each trial in the current-clamp mode. Insets show responses in expanded time scale. B, Firing probability at varying stimulation frequencies (instristic firing: n = 29; synapse-driven firing: n = 16). C, Normalized spike amplitude plotted against stimulus number. * P<0.05, ** P<0.01.