RT Journal Article
SR Electronic
T1 The Impact of SST and PV Interneurons on Nonlinear Synaptic Integration in the Neocortex
JF eneuro
JO eNeuro
FD Society for Neuroscience
SP ENEURO.0235-21.2021
DO 10.1523/ENEURO.0235-21.2021
VO 8
IS 5
A1 Christopher Dorsett
A1 Benjamin D. Philpot
A1 Spencer LaVere Smith
A1 Ikuko T. Smith
YR 2021
UL http://www.eneuro.org/content/8/5/ENEURO.0235-21.2021.abstract
AB Excitatory synaptic inputs arriving at the dendrites of a neuron can engage active mechanisms that nonlinearly amplify the depolarizing currents. This supralinear synaptic integration is subject to modulation by inhibition. However, the specific rules by which different subtypes of interneurons affect the modulation have remained largely elusive. To examine how inhibition influences active synaptic integration, we optogenetically manipulated the activity of the following two subtypes of interneurons: dendrite-targeting somatostatin-expressing (SST) interneurons; and perisomatic-targeting parvalbumin-expressing (PV) interneurons. In acute slices of mouse primary visual cortex, electrical stimulation evoked nonlinear synaptic integration that depended on NMDA receptors. Optogenetic activation of SST interneurons in conjunction with electrical stimulation resulted in predominantly divisive inhibitory gain control, reducing the magnitude of the supralinear response without affecting its threshold. PV interneuron activation, on the other hand, had a minimal effect on the supralinear response. Together, these results delineate the roles for SST and PV neurons in active synaptic integration. Differential effects of inhibition by SST and PV interneurons likely increase the computational capacity of the pyramidal neurons in modulating the nonlinear integration of synaptic output.