A Hierarchical Neuronal Model for Generation and Online Recognition of Birdsongs
Figure 4
Summary of nonlinear differential equations (1), (3), (4) and (5) (see Text S1 for Eq. (5)) that are used in the hierarchical model for birdsong generation.
Notice that the output at each level is used as an input to the lower level. Typical dynamics of HVC, RA and oscillator (Osc.) levels are given in Figure 5A, 5B and 5C, respectively. Finally, the output of the oscillator level is used in the syrinx equations to produce appropriate sound waves (Figure 6). See Table 1 for the parameters.