Lau et al. [1] showed that listeners could discriminate differences in the fundamental frequency (F0) of harmonic complex tones containing only very high frequency components, even though the discriminability of those components, when presented alone, was very poor. They attributed this finding to the operation of central pitch-sensitive neurons. We probed the characteristics of the hypothesized neurons by measuring the detection of mistuning of a single harmonic in stimuli similar to those of Lau et al. [1]. We mistuned the 8th harmonic in a complex tone containing harmonics 6–10 of an F0 of 1400 or 280 Hz with components presented either diotically or dichotically (odd harmonics in one ear and even harmonics in the other). Mistuning detection thresholds for both F0s were very low in the diotic condition, consistent with listeners detecting peripheral interactions (“beats”) between nearby harmonics. In the dichotic condition, subjects reported that, for the low F0, the mistuned component “popped out” and this led to good performance. For the high F0, no such effect was heard and performance was close to chance. Thus, if there are pitch-sensitive neurons at very high frequencies, they do not provide a basis for perceptual segregation based on mistuning.