Abstract
Pyramidal cells and interneurons expressing parvalbumin (PV), somatostatin (SST), and vasoactive intestinal peptide (VIP) show cell-type-specific connectivity patterns leading to a canonical microcircuit across cortex. Experiments recording from this circuit often report counterintuitive and seemingly contradictory findings. For example, the response of SST cells in mouse V1 to top-down behavioral modulation can change its sign when the visual input changes, a phenomenon that we call response reversal. We developed a theoretical framework to explain these seemingly contradictory effects as emerging phenomena in circuits with two key features: interactions between multiple neural populations and a nonlinear neuronal input-output relationship. Furthermore, we built a cortical circuit model which reproduces counterintuitive dynamics observed in mouse V1. Our analytical calculations pinpoint connection properties critical to response reversal, and predict additional novel types of complex dynamics that could be tested in future experiments.
Highlights
Three major non-overlapping classes of interneurons expressing parvalbumin, somatostatin and vasoactive intestinal peptide make up more than 80% of GABAergic cells of mouse cortex (Rudy et al, 2011)
Beyond the mechanistic explanation for the observed behavior in mice V1, our work provides a very general and powerful framework to explain the dynamics of neural networks with multiple interneuron types, their context-dependent interactions, and the emsergence of counterintuitive effects that may occur across different cortical structures and animals
The E population is in a low activation state the change in inhibition will have a weak effect that will not be able to reverse the response of SST. This observation provides an explanation to the reversal of the response of SST to vasoactive intestinal peptide (VIP) activation when the baseline activity is changed: as we show in Figure 2a and c for low baseline activity, MSV is negative and the presence of an external excitatory current targeting VIP cells will result in a negative response of SST cells and positive response of E, PV and VIP cells, conforming to the disinhibitory hypothesis
Summary
Three major non-overlapping classes of interneurons expressing parvalbumin, somatostatin and vasoactive intestinal peptide ( denoted PV, SST and VIP respectively) make up more than 80% of GABAergic cells of mouse cortex (Rudy et al, 2011). These neurons show cell-type-specific connectivity among themselves and with excitatory (E) neurons (Pfeffer et al, 2013; Jiang et al, 2015) forming a canonical microcircuit in the cortex. In darkness the activation of VIP cells results in an average decrease of SST population activity (Fu et al, 2014), whereas in the presence of visual stimulation the response of SST cells is reversed and its firing rate increases during locomotion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
