Hemispheric balance in processing attended and non-attended vowels and complex tones.

We compared cortical processing of attended and non-attended vowels and complex tones, using a whole-head neuromagnetometer, to test for possible hemispheric differences. Stimuli included vowels [a] and [i], spoken by two female Finnish speakers, and two complex tones, each with two pure tone components corresponding to the first and second formant frequencies (F1-F2) of the vowels spoken by speaker 1. Sequences including both vowels and complex tones were presented to eight Finnish males during passive and active (phoneme/speaker/complex tone identification) listening. Sequences including only vowels were presented to five of the subjects during passive listening and during a phoneme identification task. The vowel [i] spoken by speaker 1 and the corresponding complex tone were frequent, non-target stimuli. Responses evoked by these frequent stimuli were analyzed. Cortical activation at approximately 100 ms was stronger for the complex tone than the vowel in the right hemisphere (RH). Responses were similar during active and passive listening. Hemispheric balance remained the same when the vowel was presented in sequences including only vowels. The reduction of RH activation for vowels as compared with complex tones indicates a relative increase of left hemisphere involvement, possibly reflecting a shift towards more language-specific processing.

[1]  Riitta Salmelin,et al.  Auditory cortical activation in Finnish and Swedish speaking Finns: a magnetoencephalographic study , 2002, Neuroscience Letters.

[2]  E. Yund,et al.  Human brain specialization for phonetic attention. , 1999, Neuroreport.

[3]  M Yumoto,et al.  Brain lateralization for mismatch response to across- and within-category change of vowels , 2001, Neuroreport.

[4]  D. Poeppel,et al.  Towards a functional neuroanatomy of speech perception , 2000, Trends in Cognitive Sciences.

[5]  Riitta Hari,et al.  Selective listening modifies activity of the human auditory cortex , 2004, Experimental Brain Research.

[6]  A Schnitzler,et al.  Native language, gender, and functional organization of the auditory cortex. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[7]  R Hari,et al.  Deviant auditory stimuli activate human left and right auditory cortex differently. , 1996, Cerebral cortex.

[8]  R. Ilmoniemi,et al.  Language-specific phoneme representations revealed by electric and magnetic brain responses , 1997, Nature.

[9]  R. Zatorre,et al.  Spectral and temporal processing in human auditory cortex. , 2001, Cerebral cortex.

[10]  Alan C. Evans,et al.  Interhemispheric anatomical differences in human primary auditory cortex: probabilistic mapping and volume measurement from magnetic resonance scans. , 1996, Cerebral cortex.

[11]  R. Hari,et al.  Responses of the human auditory cortex to vowel onset after fricative consonants , 2004, Experimental Brain Research.

[12]  Jonas Obleser,et al.  Gender differences in functional hemispheric asymmetry during processing of vowels as reflected by the human brain magnetic response , 2001, Neuroscience Letters.

[13]  R. Ilmoniemi,et al.  Auditory cortex evoked magnetic fields and lateralization of speech processing , 2000, Neuroreport.

[14]  W. Singer,et al.  Interhemispheric asymmetries of the modular structure in human temporal cortex. , 2000, Science.

[15]  P. Medvick,et al.  A neuromagnetic study of selective auditory attention. , 1991, Electroencephalography and clinical neurophysiology.

[16]  P. Chauvel,et al.  Neuromagnetic source localization of auditory evoked fields and intracerebral evoked potentials: a comparison of data in the same patients , 2001, Clinical Neurophysiology.

[17]  R Salmelin,et al.  Left-hemisphere dominance for processing of vowels: a whole-scalp neuromagnetic study. , 1999, Neuroreport.

[18]  H. Rowley,et al.  A hemispherically asymmetrical MEG response to vowels. , 1999, Neuroreport.

[19]  J. Nedzelski.  Advances in Audiology , 1985 .

[20]  R. Ilmoniemi,et al.  Functional Specialization of the Human Auditory Cortex in Processing Phonetic and Musical Sounds: A Magnetoencephalographic (MEG) Study , 1999, NeuroImage.

[21]  F. Bloom,et al.  Modulation of early sensory processing in human auditory cortex during auditory selective attention. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[22]  R. Hari.  The neuromagnetic method in the study of the human auditory cortex , 1990 .

[23]  Alan C. Evans,et al.  Neural mechanisms underlying melodic perception and memory for pitch , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[24]  R. Näätänen.  Attention and brain function , 1992 .

[25]  B. Anderson,et al.  Anatomic asymmetries of the posterior superior temporal lobes: a postmortem study. , 1999, Neuropsychiatry, neuropsychology, and behavioral neurology.

[26]  K Mathiak,et al.  Encoding of temporal speech features (formant transients) during binaural and dichotic stimulus application: a whole-head magnetencephalography study. , 2000, Brain research. Cognitive brain research.

[27]  R Kakigi,et al.  Hemispheric lateralization in an analysis of speech sounds. Left hemisphere dominance replicated in Japanese subjects. , 2000, Brain research. Cognitive brain research.

[28]  R. Salmelin,et al.  Cortical processing of change detection: dissociation between natural vowels and two-frequency complex tones. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[29]  R. Ilmoniemi,et al.  Magnetoencephalography-theory, instrumentation, and applications to noninvasive studies of the working human brain , 1993 .

[30]  Bernd Lütkenhöner,et al.  High-Precision Neuromagnetic Study of the Functional Organization of the Human Auditory Cortex , 1998, Audiology and Neurotology.

[31]  D. Poeppel,et al.  Task-induced asymmetry of the auditory evoked M100 neuromagnetic field elicited by speech sounds. , 1996, Brain research. Cognitive brain research.

[32]  C Pantev,et al.  Magnetic and electric brain activity evoked by the processing of tone and vowel stimuli , 1995, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[33]  I. Johnsrude,et al.  A common neural substrate for the analysis of pitch and duration pattern in segmented sound? , 1999, Neuroreport.

[34]  J. Mäkelä,et al.  Hemispheric differences in processing tone frequency and amplitude modulations. , 1999, Neuroreport.