AUTHOR=Schulz Jan M. , Kay Jim W. , Bischofberger Josef , Larkum Matthew E. 

TITLE=GABAB Receptor-Mediated Regulation of Dendro-Somatic Synergy in Layer 5 Pyramidal Neurons

JOURNAL=Frontiers in Cellular Neuroscience

VOLUME=15

YEAR=2021

URL=https://www.frontiersin.org/journals/cellular-neuroscience/articles/10.3389/fncel.2021.718413

DOI=10.3389/fncel.2021.718413

ISSN=1662-5102

ABSTRACT=<p>Synergistic interactions between independent synaptic input streams may fundamentally change the action potential (AP) output. Using partial information decomposition, we demonstrate here a substantial contribution of synergy between somatic and apical dendritic inputs to the information in the AP output of L5b pyramidal neurons. Activation of dendritic GABA<sub><italic>B</italic></sub> receptors (GABA<sub><italic>B</italic></sub>Rs), known to decrease APs <italic>in vivo</italic>, potently decreased synergy and increased somatic control of AP output. Synergy was the result of the voltage-dependence of the transfer resistance between dendrite and soma, which showed a two-fold increase per 28.7 mV dendritic depolarization. GIRK channels activated by dendritic GABA<sub><italic>B</italic></sub>Rs decreased voltage-dependent transfer resistances and AP output. In contrast, inhibition of dendritic L-type Ca<sup>2+</sup> channels prevented high-frequency bursts of APs, but did not affect dendro-somatic synergy. Finally, we show that NDNF-positive neurogliaform cells effectively control somatic AP via synaptic activation of dendritic GIRK channels. These results uncover a novel inhibitory mechanism that powerfully gates cellular information flow in the cortex.</p>