Figure 1.

Response maps typical of the classes of ICC units exhibiting sustained responses to tones. Driven rates are calculated over a 200 ms tone duration, and spontaneous rates are subtracted to reveal inhibition. At 0 dB attenuation (attn), the sound level is ∼100 dB sound pressure level. A, Type V unit, characterized by EE responses and little to no inhibition. B, Type I unit, characterized by EI responses and sideband inhibition. C, Type O unit, characterized by an island of excitation at low levels of contralateral stimulation turning to inhibition at higher levels. Responses to ipsilateral tones are typically inhibitory.