The Journal of Neuroscience, June 17, 2009, 29(24):7718-8822; doi:10.1523/JNEUROSCI.0157-09.2009
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Brief Communications
Finding the Pitch of the Missing Fundamental in Infants
Chao He1 and
Laurel J. Trainor1,2
1Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, Ontario L8S 4K1, Canada, and 2Rotman Research Institute, Baycrest Centre, University of Toronto, Toronto, Ontario M6A 3E1, Canada
Correspondence should be addressed to Laurel J. Trainor, Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON L8S 4B2, Canada. Email: ljt{at}mcmaster.ca
Pitch perception is critical for the perception of speech and music, for object identification, and for auditory scene analysis, whereby representations are derived for each sounding object in the environment from the complex sound wave that reaches the ears. The perceived pitch of a complex sound corresponds to its fundamental frequency. However, removal of energy at the fundamental does not alter the pitch because adults use the harmonics to derive the pitch (Bendor and Wang, 2005; Trainor, 2008). Although sound frequency is represented subcortically, the integration of harmonics into a representation of pitch does not occur until auditory cortex (Bendor and Wang, 2005). Given that auditory cortex is immature in young infants, we examined the development of cortical representations for pitch by measuring electrophysiological (EEG) responses to pitch changes that required processing the pitch of the missing fundamental. Adults and infants 4 months and older showed a mismatch negativity response to these pitch changes, but 3-month-old infants did not. Thus, cortical representations of the pitch of the missing fundamental emerge between 3 and 4 months of age, indicating that there is a profound change in auditory perception for pitch in early infancy.
Received Jan. 10, 2009;
revised May 11, 2009;
accepted May 16, 2009.
Correspondence should be addressed to Laurel J. Trainor, Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON L8S 4B2, Canada. Email: ljt{at}mcmaster.ca