Frequency difference limens of C57BL/6 and DBA/2 mice: relationship to auditory neuronal response properties and hearing impairment.

Frequency difference limens (DLs) were measured in DBA/2 and C57BL/6 mice using an avoidance conditioning procedure and were viewed in relation to previously obtained neurophysiological data. DRA mice had significantly smaller DLs at 12 and 16 kHz, despite progressive sensorineural hearing loss and disrupted tonotopic organization characteristic of this strain. C57 mice had smaller DLs at 8 kHz. Several inferior colliculus (IC) neuronal response properties, that may be related to DL performance, differ between strains. Compared to C57s, a large proportion of DBA neurons respond to 12 and 16 kHz, many more best frequencies (BF, the frequency for which a neuron is most sensitive) fall between 10 and 20 kHz, response ranges are narrow, and neural intensity functions are steep. For C57 mice, a large proportion of neurons respond to 8 kHz, and more neurons have BFs between 5 and 10 kHz.