Determining the properties of a cetral pattern generator by the input-output relation of disconnected motoneurons

HORACIO ROTSTEIN; LIDIA SZCZUPAK; ROCÍO BALDERRAMA

Congreso; Escola Latino Americana de Matemática; 2018

Rhythmic oscillations are ubiquitous in the nervous system and have been implicated incognition and motor behavior in both health and disease. The so-called central patterngenerators (CPGs) are specific type of neuronal circuits that can produce the rhythmicmotor patterns that underlie behaviors such as walking, swimming, crawling andbreathing. Motoneurons respond to these CPG rhythmic patterns and control muscleactivity. The classical dogma establishes that motoneurons do not project back to theCPG. Recent work (Rotstein, Schneider, Szczupak, J. Neuroscie, 2017) has providedconvincing evidence that one type of motoneurons (CV) in the hypothesized CPG thatcontrols the rhythmic motor behavior in the leech hirudo medicinalis sends excitatoryprojections back to the CPG. Because the identity of the hypothesized CPG is not known,these studies have been carried out in an indirect way by looking at the effect thatactivation of one of the motoneurons (CV, on ?one side? of the CPG) has on the other(DE3, on the ?other side? of the CPG) under the assumption that the CPG consists of tworecurrently inhibitory neurons (one activating CV and the other DE3) and by furtherproviding evidence that these two are not connected. In this work we propose amathematical model of the neuronal circuit that can account for the observed patternbehavior in the motoneurons and we explain the underlying biophysical and dynamicmechanisms. Based on these results, we hypothesize the structure of the CPG andnetwork connectivity properties