Postnatal development of absolute auditory thresholds in kittens.

Measured postnatal development of absolute auditory thresholds in kittens from birth up to 1 mo of age. UCRs to pure tones were observed for Ss up to Day 12, and CRs were used from Day 10 onward. At 1 day after birth, the first noticeable responses were obtained in 4 of 11 Ss at frequencies of .5–2 kHz. At 2 days of age, 12 of 16 responded. Thresholds remained high (above 100 db) up to the 6th day, but the range of behaviorally effective frequencies extended from .2 to 6 kHz. All CR thresholds at Day 10 and most at Day 12 were significantly lower than those measured by UCRs. From 10 days onward, all threshold curves showed a characteristic sensitivity optimum at 4 kHz. For frequencies below 1 kHz, maximum sensitivity was reached at Day 15; for frequencies up to 20 kHz, at Day 20; and for even higher frequencies, at Day 30. At 1 mo of age, the frequency range was adultlike. Results closely follow structural maturation of the acoustic pathway and demonstrate limitations of the ability for acoustical communication during the 1st wk of life. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)