Information encoding by striatal cholinergic interneurons

GABRIEL BAGLIETTO; GONZALO SANCHEZ; GUSTAVO MURER; FERNANDO MONTANI

San Luis Potosí

Workshop; XII Latin American Workshop on Nonlinear Phenomena (LAWNP-2011); 2011

Neurons fire spikes when they are near a bifurcation from resting to spiking activity, and it is the delicate balance of the dynamical currents, and noise adaptation what determines the phase diagram of the neural activity. The mechanisms underlying transitions from resting to spiking activity in a small population of cholinergic interneurons, which are part of the striatal brain reward circuit, remain unknown. Cholinergic neurons are tonically active and present a marked spike-frequency adaptation to current injections. We investigate in the dynamical systems framework the biophysical mechanisms mediating adaptation, and the different ways in which neural information encoding is related to adaptation. More specifically, contrasting dynamical system formalisms with neurophysiological recordings of cholinergic neurons we investigate how a slow outward current inducing spike-frequency adaptation in these tonically active neurons, affects information encoding and determines its phase diagrams and its rhythmic firing activity patterns. The first step towards this end is to find a simple model capable to display the mean features of the behavior of cholinergic interneurons.  This study may help to understand why striatal cholinergic interneurons fail to encode salient environmental signals in the brain of patients with Parkinson's disease.