Cortical magnetic responses for native and non-native speech sounds: MMNm induced by English /r/ and /l/

Native Japanese-speaking adults have difficulty perceiving the English /r/ and /l/ distinction since these exact sounds are not included in the Japanese phonetic system. To investigate the neural correlate of this phenomenon we recorded cortical magnetic responses (Magnetoencephalography, MEG) from American English (AE) and Japanese (J) speakers using /ra/ and /la/ sounds. A passive oddball paradigm was used to record MMNm, an electromagnetic index of acoustic change detection. Contrary to general expectation from previous findings, MMNm was larger for J than AE speakers. Moreover, a second component identifiable as P3a peaked approximately at 250 ms, was observed only for AE not for J speakers..