The generation of respiratory rhythms in newborn mammals is critically involved in the rhythmic firing of neurons in the pre-Btzinger complex.Rhythmic activity is a complex nonlinear phenomenon in the nervous system,which manifests as diverse patterns.One special somato-dendritic bursting observed experimentally is the mixed burster.It consists of two or more different types of bursters in each period,involving extremely complex dynamic mechanisms.The introduction of magnetic flow and direct current stimulation plays an important role in regulating the firing pattern of neurons.We explore separately the effects of magnetic flow and current on the rhythmic patterns of mixed bursting within individual preBtzinger complex neurons.By fast and slow decomposition and two-parameter bifurcation analysis,the dynamic mechanism of generation and transition of mixed bursting by magnetic flow and direct current is investigated.The results show that both the magnetic flow and direct current can cause multiple changes in the increase and decrease of the number of somatic bursts in the mixed bursting. Different from other phenomena in which the number of mixed bursting is monotonically increased or decreased,the results show the diversity phenomenon of rhythm activity.The results of the present study may help to reveal and explain the dynamic mechanism of the complex mixed pattern of respiratory rhythm.