Figure 7.
AM and FM are important features for creating selective neural responses. A, B, The FRAs of two neurons. C, This neuron consistently responded to the natural 40 kHz harmonic vocalization (RXN = 0.40), which was predicted by the pure tone model. D, The lack of response to the no-AM variant is indicated by the reduced RXM value, low response similarity (SXY = 0.02), and large, positive selectivity index (D = 0.37). The predicted response was also attenuated as a result of increased power introduced into the inhibitory sideband captured by the model. E, This neuron showed a robust response to the natural 30 kHz vocalization, which was not captured by the model because the spectral power of the vocalization lies outside the FRA of the neuron. F, The response was significantly reduced after removal of the FM from this vocalization.