RT Journal Article SR Electronic T1 Action potential counting at giant mossy fiber terminals gates information transfer in the hippocampus JF bioRxiv FD Cold Spring Harbor Laboratory SP 158444 DO 10.1101/158444 A1 Simon Chamberland A1 Yulia Timofeeva A1 Alesya Evstratova A1 Kirill Volynski A1 Katalin Tóth YR 2017 UL http://biorxiv.org/content/early/2017/07/04/158444.abstract AB Hippocampal mossy fibers have long been recognized as conditional detonators owing to prominent short-term facilitation, but the patterns of activity required to fire postsynaptic CA3 pyramidal neurons remain poorly understood. We show that mossy fibers count the number of spikes to transmit information to CA3 pyramidal cells through a distinctive interplay between presynaptic calcium dynamics, buffering and vesicle replenishment. This identifies a previously unexplored information coding mechanism in the brain.