Figure 5. Hypothetical model showing the interaction between excitatory and inhibitory inputs. (A) Frequency-threshold response tuning curves showing the inputs to a neuron in the central auditory pathway. Neurons in the central auditory pathway receive excitatory inputs (solid line) and inhibitory inputs (hatched area). In this model, the CF of the inhibitory input is located at a frequency slightly higher than the excitatory input. The hypothetical neuron produces an excitatory response if the excitatory input has a lower threshold than the inhibitory input. (B) Hypothetical excitatory response area resulting from the inputs shown in panel A. (C) Discharge rate-level function of the model when the frequency of the tone is near the excitatory CF. At low sound levels, the discharge rate increases monotonically because the neuron is only activated by the excitatory inputs. However, at higher intensities, the inhibitory inputs are activated. This inhibits the discharge rate at suprathreshold intensities resulting in a nonmonotonic rate-level function (from Salvi et al, 1998 with permission).