Spectro-temporal receptive fields of midbrain auditory neurons in the rat obtained with frequency modulated stimulation.

Single unit responses at the auditory midbrain of the anesthetized rat were characterized in terms of spectro-temporal receptive field (STRF) using random frequency modulated (FM) tones and peri-spike averaging. STRFs were obtained from 121 FM-sensitive units covering a wide range of characteristic frequency (CF). Roughly half of the neurons showed clearly preferred stimulus time profiles that formed either a single, double or multiple bands. Neurons with a single-band STRF appeared to be sorted into positive or negative directional sensitivity for FM modulation on the basis of their CF either below or above 10 kHz. This directional selectivity is discussed in relation to the most sensitive part of the rat's audiogram.