Functional maturation of striatal cholinergic interneurons during adolescence

CECILIA TUBERT; GONZALO SANCHEZ; LORENA RELA; MARIO GUSTAVO MURER

Huerta Grande, Córdoba

Congreso; XXVI Congreso Anual SAN; 2011

Sociedad Argentina de Investigación en Neurociencias

Acetylcholine released by a small population of interneurons, referred to as ?tonically active neurons? (TANs), is a main modulator of striatal function. The tonic activity of cholinergic interneurons depends on intrinsic mechanisms. Action potentials open Cav channels and activate Ca2+ dependent K+ currents. This leads to an afterhyperpolarization (AHP) with three phases: fAHP, mAHP, and sAHP, which produces the activation of Ih. Previous results show that intrinsic properties of TANs mature during adolescence. We propose that KCNQ channels with atypical properties, activated by Cav through the hipocalcin, mediate a protracted maturation of the AHPs. Increases in one or more components could explain the more marked firing adaptation in adult compared to juvenile TANs. Firing frequency adaptation defines neurons computational properties. Neurons with more marked IsAHP and Ih may act as resonators and codify the signals in the temporal precision of each spike. We propose that differences in the frequency adaptation between juvenile and adult TANs determine how they codify environmental cues during instrumental learning.