FIG. 10.

Examples of selective monopolar tuning for units at two inferior colliculus depths in a cat. Each column shows recorded waveforms at a given IC depth in response to three stimulating channels (inset bottom right channel number). A threshold (horizontal line) was empirically chosen to detect only one to several large-spiking units. Recordings from the 1.2 mm deep recording site (left) show sustained responses to channel 3 MP but not to 1 or 5 MP. In contrast, the recording site at 2.3 mm (right), shows sustained responses to 5 MP but not to 1 or 3 MP. Both recording sites show onset responses to all three stimulating channels. Current levels were 1 MP, 280 μA; 3 MP, 250 μA; and 5 MP, 450 μA. Pulse trains began at 0 ms and ended at 200 ms.