FIG. 7.
Variation of the strength of phase locking with CF, stimulus frequency and SR. A Average strength of phase locking, expressed as VS, for responses to tones presented at 70 dB SPL. Abscissa: stimulus frequency. Open symbols: all SRs. Open circles: CFs > 4 kHz. Open squares: CFs < 3 kHz. Dots indicate highly significant differences between VSs for ANFs with CFs < 3 kHz and >4 kHz. Filled symbols: low-SR (≤1 spike/s) ANFs. Filled squares: low-SR ANFs with CFs < 3 kHz. Filled circles: low-SR ANFs with CFs > 4 kHz. Inset: maximal VSs for ANFs in chinchilla (open symbols), cat (solid line), and guinea pig (dashed line). The maximal VSs for chinchilla at frequencies lower and higher than 800 Hz correspond, respectively, to the averages for CFs > 4 and <3 kHz. Cat and guinea pig data are averages computed within 0.1-decade bins (Fig. 3 of Weiss and Rose 1988) from the original data of Johnson (1980) and Palmer and Russell (1986), respectively. B VS for responses to 2.5-kHz tones presented at 70 dB SPL plotted against CF (open symbols). Filled symbols: VS averages, computed in nonoverlapping 1/3-octave CF bands. Black lines: linear fits to the VS values for CFs < 3, 3–4, and >4 kHz. Gray area encompasses responses with presumably saturated VS. CCircles: rate thresholds for 2.5-kHz tones; squares: rate thresholds +10 dB. Horizontal line marks 70 dB SPL, the level of the 2.5-kHz tone stimulus.