COGNITIVE NEUROSCIENCE AND NEUROPSYCHOLOGYSimultaneous pitches are encoded separately in auditory cortex: an MMNm studyFujioka, Takakoa; Trainor, Laurel J.a b c; Ross, BernhardaAuthor Information aRotman Research Institute, Baycrest, University of Toronto bDepartment of Psychology, Neuroscience and Behaviour cMcMaster Institute for Music and the Mind, McMaster University, Hamilton, Canada Correspondence to Takako Fujioka, PhD, Rotman Research Institute, 3560 Bathurst Street, Toronto, Ontario, M6A 2E1, Canada Tel: +1 416 785 2500 x 3413; fax: +1 416 785 2862; e-mail: email@example.com Received 26 November 2007; accepted 4 December 2007 NeuroReport: February 12th, 2008 - Volume 19 - Issue 3 - p 361-366 doi: 10.1097/WNR.0b013e3282f51d91 Buy Metrics Abstract This study examined whether two simultaneous pitches have separate memory representations or an integrated representation in preattentive auditory memory. Mismatch negativity fields were examined when a pitch change occurred in either the higher-pitched or the lower-pitched tone at 25% probability each, thus making the total deviation rate of the two-tone dyad 50%. Clear MMNm was obtained for deviants in both tones confirming separate memory traces for concurrent tones. At the same time, deviants to the lower-pitched, but not higher-pitched, tone within the two-tone dyad elicited a reduced MMNm compared to when each tone was presented alone, indicating that the representations of two pitches are not completely independent. © 2008 Lippincott Williams & Wilkins, Inc.