Sensitivity of cat primary auditory cortex (AI) neurons to the direction and rate of frequency modulation.
Responses of 65 single auditory cortex (AI) neurons to frequency-modulated (FM) sweeps with different rates and direction of frequency change were examined quantitatively. Most units responded differentially depending on the characteristics of the FM sweep stimulus. Sixty-five percent of the units encountered responded at least twice as well for one direction of the FM sweep as for the other direction. Of these direction selective neurons, 67% preferred downward-directed FM sweeps (i.e. changing from high to low frequencies) while only 33% preferred upward-directed FM sweeps. The preference for downward-directed FM sweeps was especially clear in EI cells. In addition, cortical neurons often displayed sensitivity to the rate of frequency modulation (speed sensitivity).
D000161:Acoustic Stimulation; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology / Q000502:physiology*; D002415:Cats; D005072:Evoked Potentials, Auditory; D009474:Neurons / Q000145:classification / Q000502:physiology