We investigated bursting behavior in rodent trigeminal neurons. The es
sential mechanisms operating in the biological systems were determined
based on testable predictions of mathematical models. Bursting activi
ty in trigeminal motoneurons is consistent with a traditional mechanis
m employing a region of negative slope resistance in the steady-state
current-voltage relationship (Smith, T. G. 1975. Nature. 253:450-452).
However, the bursting dynamics of trigeminal interneurons is inconsis
tent with the traditional mechanisms, and is far more effectively expl
ained by a new model of bursting that exploits the unique stability pr
operties associated with spike threshold (Baer, S. M., T. Emeux, and J
. Rinzel. 1989. SIAM J. Appl. Math. 49:55-71).