ASA 124th Meeting New Orleans 1992 October

4aPP6. Intervocalic stop consonant representation in the chinchilla auditory nerve.

S. Shyamla Narayan

Donna J. Beehler

Donal G. Sinex

Boys Town Natl. Res. Hospital, 555 N. 30th St., Omaha, NE 68131

The representation of intervocalic voiced and voiceless stop consonants in the chinchilla auditory nerve was studied. Acoustic characteristics of intervocalic stop consonants differ from those of stops in other positions. The stimuli (/ita/, /ida/, /uta/, and /uda/ as spoken by male and female talkers) were presented at 30 and 60 dB SPL. At both stimulus levels, discharge rates of most neurons decreased during the consonant closures. For the voiceless consonant /t/, discharge rates usually decreased to the spontaneous rates. For the voiced consonant /d/, the low-frequency neurons continued to respond to the ``voice bar'' during closure. At 60 dB SPL, the release for all sounds elicited increases in the discharge rates of the higher CF neurons. At 30 dB SPL, the release did not elicit rate increases above the rate during closure in any CF region. At both stimulus levels, the onset of voicing after the release nearly always elicited discharge rate increases. Neurons with CFs below 2 kHz were most likely to respond to voicing. [Work supported by DC00341 to DGS.]