Detection of determinism within time series of irregular burst firing fromthe injured sensory neuron

Irregular burst firing is spontaneously generated by rat dorsal root gangli on neuron after chronic compression. To investigate the time series of burs t firing, we recorded interspike intervals (ISIs) of single-unit firing in vitro and processed the ISIs to obtain interevent intervals (IEIs). Then, t wo non-linear methods were applied to detect deterministic dynamic behavior s in IEI series. No evidence for the existence of determinism was found wit h non-linear prediction method. Using unstable periodic orbit identificatio n method, significant period-1 orbits were identified in all 10 data, perio d-2 orbits in eight, and period-3 orbits in six. The results indicate that there exist significant deterministic behaviors in the time series of irreg ular burst firing from the injured sensory neuron. NeuroReport 11:3295-3298 (C) 2000 Lippincott Williams & Wilkins.