Neural Activity in the Ventral Pallidum Encodes Variation in the Incentive Value of a Reward Cue

Abstract

There is considerable individual variation in the extent to which reward cues are attributed with incentive salience. For example, a food-predictive conditioned stimulus (CS; an illuminated lever) becomes attractive, eliciting approach toward it only in some rats ("sign trackers," STs), whereas others ("goal trackers," GTs) approach the food cup during the CS period. The purpose of this study was to determine how individual differences in Pavlovian approach responses are represented in neural firing patterns in the major output structure of the mesolimbic system, the ventral pallidum (VP). Single-unit in vivo electrophysiology was used to record neural activity in the caudal VP during the performance of ST and GT conditioned responses. All rats showed neural responses to both cue onset and reward delivery but, during the CS period, STs showed greater neural activity than GTs both in terms of the percentage of responsive neurons and the magnitude of the change in neural activity. Furthermore, neural activity was positively correlated with the degree of attraction to the cue. Given that the CS had equal predictive value in STs and GTs, we conclude that neural activity in the VP largely reflects the degree to which the CS was attributed with incentive salience.

Optogenetic Inhibition of Ventral Pallidum Neurons Impairs Context-Driven Salt Seeking

“…Thus, it is unknown whether mechanisms for salt seeking are the same as, or dissociable from, those for the primary motivation to consume salt. One likely candidate for regulating salt-seeking is the VP, a key region for motivated behavior (Cromwell and Berridge, 1993;Smith et al, 2009;Root et al, 2015;Ahrens et al, 2016). Of note, VP neurons do not normally respond to cues predicting an aversive salt outcome (Tindell et al, 2009).…”

For Value or for Worth? Part 1: Speaking Syllogistic Attractors of Appropriations in a Thought-Action-Mood-Space

“…Cued temptation also correlates with activity in the mesolimbic output structure ventral putamen [37]. In primates and rats [38] the ventral striatum and ACC seem central to effort-discounting, while in fMRI [39] the posterior OFC and insula seemingly are ignited by anticipated worth processed in 5+DA~.…”

Ventral pallidum neurons signal relative threat

“…The VP is consistently implicated in reward processes 20,[23][24][25][26][27][28] . VP neurons acquire firing to reward-predictive cues [29][30][31] and show differential firing to cues predicting different reward sizes 32,33 . VP neurons change their firing when a taste changes from palatable to aversive 34 .…”