Duifhuis Pitch : Neuromagnetic representation and auditory modeling 1

24 When a high harmonic is removed from a cosine-phase harmonic complex, we hear a 25 sine tone pop out of the perception; the sine tone has the pitch of the high harmonic while the 26 tone complex has the pitch of its fundamental frequency, f0. This phenomenon is commonly 27 referred to as Duifhuis Pitch (DP). This paper describes, for the first time, the cortical 28 representation of DP observed with magnetoencephalography. In Experiment 1, conditions 29 that produce the perception of a DP were observed to elicit a classic onset response in 30 auditory cortex (P1m, N1m, P2m), and an increment in the sustained field (SF) established in 31 response to the tone complex. Experiment 2 examined the effect of the phase spectrum of the 32 complex tone on the DP activity: Schroeder-phase negative waves elicited a transient DP 33 complex with a similar shape to that observed with cosine-phase waves but with much longer 34 latencies. Following the transient DP activity, the responses of the negative and positive 35 Schroeder-phase waves converged and the increment in the SF slowly died away. In the 36 absence of DP, the two Schroeder-phase conditions with low peak factors both produced 37 larger SFs than cosine-phase waves with large peak factors. A model of the auditory 38 periphery that includes coupling between adjacent frequency channels is used to explain the 39 early neuromagnetic activity observed in auditory cortex. 40 41 42 43 44 45 46 47 48 49 List of abbreviations 50 AEF auditory evoked field 51 BMM basilar membrane motion 52 BTL Bradley-Terry-Luce technique 53 COS cosine phase 54 DP Duifhuis Pitch 55 f0 fundamental frequency 56 GT-AFB gammatone auditory filterbank 57 HCT harmonic complex tone 58 HG Heschl’s gyrus 59 MEG magnetoencephalography 60 MP musical pitch 61 PT Planum temporale 62 RAND random phase wave 63 SCHR+/positive/negative Schroeder phase 64 SF sustained field 65 SIN sine phase 66 SSR steady-state response 67 TL-AFB transmission-line auditory filterbank 68 69 70 71 72 73 74 75