Hemispheric lateralization in an analysis of speech sounds - Left hemisphere dominance replicated in Japanese subjects

Evoked magnetic responses to speech sounds [R. Naatanen, A. Lehtokoski, M. Lennes, M. Cheour, M. Huotilainen, A. Iivonen, M. Vainio, P. Alku, R.J. Ilm oniemi, A. Luuk, J. Allik, J. Sinkkonen and K. Alho, Language-specific phon eme representations revealed by electric and magnetic brain responses. Natu re, 385 (1997) 432-434.] were recorded from 13 Japanese subjects (right-han ded). Infrequently presented vowels ([o]) among repetitive vowels ([e]) eli cited the magnetic counterpart of mismatch negativity, MMNm (Bilateral, nin e subjects; Left hemisphere alone, three subjects; Right hemisphere alone, one subject). The estimated source of the MMNm was stronger in the left tha n in the right auditory cortex. The sources were located posteriorly in the left than in the right auditory cortex. These findings are consistent with the results obtained in Finnish [R. Naatanen, A. Lehtokoski, M. Lennes, M. Cheour, M. Huotilainen, A. Iivonen, M.Vainio, P.Alku, R.J. Ilmoniemi, A. L uuk, J.,Allik, J. Sinkkonen and K. Alho, Language-specific phoneme represen tations revealed by electric and magnetic brain responses. Nature, 385 (199 7) 432-434.][T. Rinne, K. Alho, P. Alku, M. Holi, J. Sinkkonen, J. Virtanen , O. Bertrand and R. Naatanen, Analysis of speech sounds is left-hemisphere predominant at 100-150 ms after sound onset. Neuroreport, 10 (1999) 1113-1 117.] and English [K. Alho, J.F. Connolly, M. Cheour, A. Lehtokoski, M. Huo tilainen, J. Virtanen, R. Aulanko and R.J. Ilmoniemi, Hemispheric lateraliz ation in preattentive processing of speech sounds. Neurosci. Lett., 258 (19 98) 9-12.] subjects. Instead of the Plm observed in Finnish [M. Tervaniemi, A. Kujala, K. Alho, J. Virtanen, R.J. Ilmoniemi and R. Naatanen, Functiona l specialization of the human auditory cortex in processing phonetic and mu sical sounds: A magnetoencephalographic (MEG) study. Neuroimage, 9 (1999) 3 30-336.] and English [K. Alho, J.F. Connolly, M. Cheour, A. Lehtokoski, M. Huotilainen, J. Virtanen, R. Aulanko and R.J. Ilmoniemi, Hemispheric latera lization in preattentive processing of speech sounds. Neurosci. Lett., 258 (1998) 9-12.] subjects, prior to the MMNm, M60, was elicited by both rare a nd frequent sounds. Both MMNm and M60 sources were posteriorly located in t he left than the right hemisphere. (C) 2000 Elsevier Science B.V. All right s reserved.