RT Journal Article SR Electronic T1 Conditioning by Subthreshold Synaptic Input Changes the Characteristic Firing Pattern of CA3 Hippocampal Neurons JF bioRxiv FD Cold Spring Harbor Laboratory SP 084152 DO 10.1101/084152 A1 Saray Soldado-Magraner A1 Federico Brandalise A1 Suraj Honnuraiah A1 Michael Pfeiffer A1 Urs Gerber A1 Rodney Douglas YR 2017 UL http://biorxiv.org/content/early/2017/03/30/084152.abstract AB Neurons are typically classified according to their intrinsic firing patterns and distinctive morphological features. However, our experiments in the CA3 field of rat hippocampus in vitro revealed that discharge patterns change significantly following a short period of low frequency subthreshold stimulation of the neuron’s afferents. This effect could be reproduced by intrasomatic current pulses and was blocked by kinase inhibitors. Cluster analysis of the firing patterns before and after conditioning revealed systematic transitions towards adapting and intrinsic burst behaviours, irrespective of the initial pattern exhibited by the cell. Using a conductance-based model, we demonstrate that the observed transitions can be mediated by recruitment of calcium and M-type potassium conductances. We conclude that CA3 neurons adapt their conductance profile to the statistics of ongoing activity in their embedding circuits, making their intrinsic firing pattern not a constant signature, but rather the reflection of long-term circuit activity.