Fig. 2

Wave speeds for different transmission speed and feedback delay distributions in class (A), (B) and (C) of the spatial kernel function K with an excitatory feedback $W\ge 0$. The transmission speed and feedback delay distributions are taken from Eqs. (2) with $c_1=2c_0$ and ${\tau }_1=2{\tau }_0$. Panels a and b give the speeds for class (A), panels c and d for class (B) and panels e and f for class (C). The delays τ in a, c and e are identical to the lowest delays ${\tau }_0$, the transmission speeds c in b, d and f are identical to the lowest transmission speed $c_0$ in the distribution. Other kernel parameters are taken from Fig. 3