The cortical evoked response elicited by nine plosives in normal hearing listeners

P1-N1-P2 complex reflecting pre-attentive processing of sound presents several temporally overlapping and spatially distributed neural sources in or near primary auditory cortex. This study investigated cortical evoked responses to the P1-N1-P2 complex to determine the perceptual contributions of the acoustic features.

Eleven young native-speaking Korean adults with normal hearing participated. The stimuli were three bilabial, three alveolar, and three velar syllables, and each place of articulation had one lax, one tense, and one aspirate syllable as the manner of articulation.

The results indicate the cortical responses to the velar syllables significantly differed from the bilabial and alveolar groups at the P1-N1 and N1-P2 interamplitude. However, there is no significant difference in the cortical responses between Korean lax and tense syllables, which is significant for English phonology in terms of voice onset time. Further, the cortical responses to aspirate syllables significantly differed from two other groups in the interamplitude, demonstrating that the /t(h)a/ syllable had the largest response at N1-P2 interamplitude.

Different speech sounds evoked different P1-N1-P2 patterns in the place and the manner of articulation in terms of interamplitude, but not of the latency and interlatency although further studies should be followed.