Perceived pitch typically depends on the fundamental frequency, though the dependence could be mediated solely by the presence of harmonics corresponding to that fundamental frequency. The perception of a pitch without the corresponding fundamental frequency in the physical stimulus is called the pitch of the missing fundamental.[1] Neurons lateral to A1 in marmoset monkeys were found to be sensitive specifically to the fundamental frequency of a complex tone,[19] suggesting that pitch constancy may be enabled by such a neural mechanism.