Ventral arkypallidal neurons modulate accumbal firing to promote reward consumption

Abstract

A pause in firing of nucleus accumbens shell (NAcSh) neurons is critical for reward consumption; however, the substrate driving this pause is unknown. While ventral pallidal (VP) activity encodes reward value, the specific roles of VP subpopulations in computation and expression of this value are poorly understood. Here, we establish that inhibitory input from the VP is crucial for reward-related inhibition of NAc firing. A sparse, non-canonical subpopulation of VP neurons, the so-called "ventral arkypallidal (vArky)" neurons makes inhibitory synaptic contacts throughout the NAcSh, and drives inhibition of NAcSh neurons in vivo. Moreover, endogenous calcium activity of vArky neurons predicted subsequent reward consumption behavior, while optogenetically activating this pathway increased reward consumption by amplifying hedonic value of reward. Classically, the VP is considered downstream of the NAc; however, our results challenge this view and establish that vArky neurons in the VP promote reward consumption via potent modulation of NAcSh firing.

An open-source device for measuring food intake and operant behavior in rodent home-cages

“…Since its original publication, we have redesigned the FED twice and here present the 3 rd version of FED, which revamps our original design and adds the ability to measure operant behavior, as well as a unique "angled" pellet dispenser mechanism that is resistant to jamming. We distributed the design for FED3 online and it has been used to study how specific neural circuit manipulations alter food motivation (Mazzone et al, 2020;Sciolino et al, 2019;Vachez et al, 2021), how weight-loss alters food motivation (Matikainen-Ankney et al, 2020), and how food motivation is altered in a stress-susceptible mouse population (Rodriguez et al, 2020). FED3 is a stand-alone solution for home-cage operant training, enabling researchers to understand not just total food intake, but also motivation for and learning about food rewards.…”

“…Due to wiring, connecting FED3 to external hardware likely requires FED3 to be used outside of the home-cage, or to modify the home-cage system. This has been done by multiple labs to synchronize the output of FED3 with fiber-photometry recordings (London et al, 2018;Mazzone et al, 2020), electrophysiological recordings (London et al, 2018), optogenetic stimulation (Vachez et al, 2021), and video tracking (Krynitsky et al, 2020;Li et al, 2019); and 4) FED3 is open-source and all design files and code are freely available online. This enables users to modify the code and hardware to achieve new functionality.…”

Feeding Experimentation Device version 3 (FED3): An open-source home-cage compatible device for measuring food intake and operant behavior

“…Since its original publication, we have redesigned the FED twice and here present the 3 rd version of FED, which revamps our original design and adds the ability to measure operant behavior, as well as a unique "angled" pellet dispenser mechanism that is resistant to jamming. We distributed the design for FED3 online and it has already been used to study how specific neural circuit manipulations alter food motivation (Mazzone et al, 2020;Sciolino et al, 2019;Vachez et al, 2020), how weight-loss alters food motivation (Matikainen-Ankney et al, 2020), and how food motivation is altered in a stress-susceptible mouse population (Rodriguez et al, 2020).…”

“…Due to its small size it can also be placed inside of other equipment where wires might be impractical, such as within an indirect calorimetry system; 3) FED3 has a programmable output that allows it to easily synchronize with other equipment. This has already been used by multiple labs to synchronize the output of FED3 with fiber-photometry recordings (London et al, 2018;Mazzone et al, 2020), electrophysiological recordings (London et al, 2018), optogenetic stimulation (Vachez et al, 2020), and video tracking (Krynitsky et al, 2020;Li et al, 2019); and 4) FED3 is open-source with all design files and code freely available online. This enables users to modify the code and hardware to achieve new functionality.…”

Distinct threat and valence signals in rat nucleus accumbens core

“…Coefficient of variance is a relative measure of the variability of spike firing, with small values indicating less variation in inter-spike intervals (more regular firing), and large values more variability (less regular firing) (Saeb-Parsy and Dyball, 2003; Moaddab et al, 2015). Waveform peak-valley duration was the x-axis distance between the valley of depolarization and the peak of after-hyperpolarization with smaller values indicating narrow waveforms (Gage et al, 2010; Gittis et al, 2011; Vachez et al, 2021).…”