Changes in P300 neural correlates during voice-pitch discrimination under conditions supporting F0-based auditory segregation

Previous event-related potential (ERP) studies have examined effects of tone frequency, level, and duration on P300 amplitude and latency during two-tone frequency discrimination using the oddball paradigm. However, these studies have focused outside voice-pitch frequency range, where fundamental frequency (F0) differences are critical for auditory scene segregation. The current study investigates how F0 differences and moderate tone levels influence P300 amplitude and latency during two-tone F0 discrimination. Younger adults with normal hearing heard standard and deviant tones in oddball paradigm. The standard tone had an F0 of 100 Hz, while deviant tone had F0s of 103, 106, 126, and 179 Hz, corresponding to F0 differences of 3, 6, 26, and 79 Hz. Tones were 400 ms duration and presented at 65 or 75 dB SPL. F0 difference and duration were selected to ensure reliable F0 discrimination and segregation. P300 responses were examined by analyzing ERPs for standard and deviant trials. Mean parietal P300 amplitudes were significantly higher from 6 Hz to 26 Hz and 26 Hz to 79 Hz at both levels, whereas mean parietal P300 latencies were significantly shorter at 79 Hz than at 26 Hz. Higher behavioral discrimination performance (d') was significantly related to stronger mean parietal P300 amplitudes but not to shorter mean parietal P300 latencies. These findings suggest that P300 amplitude provides a more informative index of the neural processing underlying two-tone voice-pitch discrimination when F0-based segregation cues are available.