Physiological patterns of simulated excitatory synaptic conductance can cause a slow rate increase. A, Example of a conductance stimulus (bottom), the resulting injected current (middle), and the voltage response (top) in dynamic clamp. B, PSTH of responses to simulated synaptic inputs phase-locked to 500 and 1000 Hz. C, Mean change in firing rate versus the phase-locking frequency imposed on the simulated synaptic inputs (n indicated above each bar). Error bars represent SE (z test, *p < 0.01).