Abstract
The processing of spectral and temporal information in the core fields of the left and right auditory cortices of the guinea pig was investigated using optical imaging with a voltage-sensitive dye (RH795). Seventeen guinea pigs were anesthetized with ketamine (80mg/kg) and xylazine (40mg/kg). In order to compare the functional difference between the left and the right auditory cortex, optical imaging patterns to repeated sound ( tone, click, harmonic noise and native sound (Qui sound)) at different repetition rates (4-20 Hz) were recorded from core auditory fields (primary (AI), dorsocaudal (DC) fields) of both sides. Repetition rate transfer functions (RRTF) in field AI were low-pass showing a sharp drop-off in evoked activity per click or noise above 10 Hz but RRTFs in field DC were bandpass with the peak of 8 or 10 Hz. The cut-off frequencies of RRTF in the left cortex were the same as those in the right cortex but the slopes of the RRTF in the left cortex were sharper. On the other hand, The slopes of RRTF per tone or Qui sound in field AI of the wider cortex were gentler than those in the narrower one. We discuss the functional difference between the left and right auditory cortices of guinea pigs. [J Physiol Sci. 2007;57 Suppl:S113]
