Tone-threshold mapping in the inferior colliculus of the house mouse.

The distribution of lowest tone-response thresholds was examined within 3 different isofrequency planes (10, 20 and 30 kHz) of the inferior colliculus (IC) of the house mouse. Lowest thresholds are located in, or slightly rostrolateral to the center of each isofrequency plane. Thresholds increase centrifugally, although in the rostrolateral direction the increase is less marked. The data show that, in addition to the dorsoventrally oriented tonotopical arrangement, there is a horizontal representation of thresholds within each isofrequency plane of the IC.