Predominantly linear summation of metabotropic postsynaptic potentials follows coactivation of neurogliaform interneurons

eLife

Gábor Tamás¹  Gergely Komlósi¹  Gáspár Oláh¹  Judith Baka¹  Attila Ozsvár¹  Gábor Molnár¹ 

[1] MTA-SZTE Research Group for Cortical Microcircuits of the Hungarian Academy of Sciences,, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary;

关键词: cerebral cortex;    interneuron;    microcircuit;    GABA;    synaptic transmission;    Mouse;    Rat;   

DOI  :  10.7554/eLife.65634

来源: eLife Sciences Publications, Ltd

【 摘 要 】

Summation of ionotropic receptor-mediated responses is critical in neuronal computation by shaping input-output characteristics of neurons. However, arithmetics of summation for metabotropic signals are not known. We characterized the combined ionotropic and metabotropic output of neocortical neurogliaform cells (NGFCs) using electrophysiological and anatomical methods in the rat cerebral cortex. These experiments revealed that GABA receptors are activated outside release sites and confirmed coactivation of putative NGFCs in superficial cortical layers in vivo. Triple recordings from presynaptic NGFCs converging to a postsynaptic neuron revealed sublinear summation of ionotropic GABAA responses and linear summation of metabotropic GABAB responses. Based on a model combining properties of volume transmission and distributions of all NGFC axon terminals, we predict that in 83% of cases one or two NGFCs can provide input to a point in the neuropil. We suggest that interactions of metabotropic GABAergic responses remain linear even if most superficial layer interneurons specialized to recruit GABAB receptors are simultaneously active.

【 授权许可】

CC BY