THE NEUROSCIENCES AND MUSIC III—DISORDERS AND PLASTICITY Automatic Brain Responses to Pitch Changes in Congenital Amusia Patricia Moreau, Pierre Jolicœur, and Isabelle Peretz BRAMS, Universit´ e de Montr´ eal, Qu´ ebec, Canada Congenital amusia is a lifelong disorder affecting the processing of pitch. This pitch deficit can be traced down to abnormal brain responses elicited by pitch changes smaller than a semitone in conditions requiring attention. Here, we use the mismatch negativ- ity (MMN) to investigate pre-attentive pitch change detection in 10 amusics and eight matched controls. Results indicate similar MMN in amusics and controls, even for an eighth of a tone change, revealing that the amusic brain can process small pitch changes at a pre-attentive level. Thus, the pitch deficit in congenital amusia may be related to a problem of perceptual awareness. Key words: congenital amusia; auditory ERP; mismatch negativity; pitch change detection Introduction Congenital amusia is a lifelong disorder that is characterized by difficulties in acquiring ba- sic musical skills, such as music perception and recognition despite normal hearing and intelli- gence. 1 Behavioral studies have shown that the deficit underlying congenital amusia is critically dependent upon fine-grained pitch discrimina- tion. 2,3 Indeed, when asked to detect a deviant tone that varies in pitch within a sequence of successive identical tones, amusics have prob- lems detecting pitch changes that are smaller than a semitone. 2 In a recent electrophysiology study, Peretz et al. 4 found that the fine-grained deficits in pitch processing could be related to abnor- mal electrical brain responses. They measured the electroencephalogram (EEG) and used the event-related potential (ERP) method to exam- ine brain responses in amusic individuals while they were monitoring short sequences of tones for the presence of a pitch change. They found Address for correspondence: Patricia Moreau, BRAMS, Universit´ e de Montr´ eal, 1430 Boulevard Mont-Royal, Outremont, Montr´ eal, Qu´ ebec, H2V 4P3, Canada. Voice: +514-343-6111, ext. 2799; fax: +514-343- 5787. patricia.moreau@umontreal.ca that the amusic brain did not respond to pitch deviances smaller than one semitone, whereas the normal brain did so reliably. In contrast, the amusic brain “over-reacted” to large pitch changes, by eliciting an N2 wave (which was not present in normals) and a P3 wave that was almost twice as large as that observed in con- trols’ brains. These results suggest that the pitch deficit underlying congenital amusia might de- pend on limited attentional resources. Here, we tested this attentional hypothesis by assessing the presence of a mismatch nega- tivity (MMN) wave in response to small pitch deviations in amusia. The MMN wave is an ERP component known to reflect pre-attentive change detection. 5 According to a recent study by Braun et al., 6 the MMN should be altered in tune-deafness. However, the tune-deaf popula- tion tested by Braun et al. 6 was selected on dif- ferent criteria than the ones used here. There- fore, it was important to assess the MMN in amusia with the same population and the same experimental context as used previously, 4 under controlled attentional demands. In the present study, we used the MMN to investigate auto- matic pitch change detection in an acoustical context in individuals suffering from congenital amusia. The Neurosciences and Music III—Disorders and Plasticity: Ann. N.Y. Acad. Sci. 1169: 191–194 (2009). doi: 10.1111/j.1749-6632.2009.04775.x c  2009 New York Academy of Sciences. 191