Development of auditory sensitivity of altricial birds: absolute thresholds of the generation of evoked potentials.

The thresholds of the generation of EP in the L field of two to nine day old pied flycatcher nestlings in response to monotonal bursts of varied frequency were investigated. The entire range of auditory sensitivity was divided into three channels on the basis of the character of the age-related dynamics of the thresholds (two to nine days of life): low-frequency (0.3-1.6 kHz), middle- (1.5-4.0 kHz), and high-frequency (5.0-8.0 kHz). Widening of the auditory range in the direction of high frequencies on the 4th to 5th days of nest life was demonstrated. It was shown that the development of auditory sensitivity continues in all three channels in the post-embryonic period (two to nine days after hatching), and that each of these is characterized by its own thresholds time course.