Direct and indirect dorsolateral striatum pathways reinforce different action strategies - PubMed (original) (raw)
Direct and indirect dorsolateral striatum pathways reinforce different action strategies
Ana M Vicente et al. Curr Biol. 2016.
Abstract
The basal ganglia, and the striatum in particular, are critical for action reinforcement [1,2]. The dorsal striatum, which can be further subdivided into dorsomedial (DMS) and dorsolateral (DLS) striatum, is mainly composed of two subpopulations of striatal medium spiny projection neurons (MSNs): dopamine D1 receptor-expressing MSNs that constitute the striatonigral or direct pathway (dMSNs); and dopamine D2 receptor-expressing MSNs that constitute the striatopallidal or indirect pathway (iMSNs) [3]. It has been suggested that each pathway has opposing roles in reinforcement, with dMSNs being important to learn positive reinforcement and iMSNs to learn to avoid undesired actions (Go/No-Go) [1]. Furthermore, optogenetic self-stimulation of dMSNs in DMS leads to reinforcement of actions, while self-stimulation of iMSNs leads to avoidance of actions [2]. However, in DLS, which has been implicated in the consolidation of well-trained actions and habits in mice [4,5], both pathways are active during lever-pressing for reward [6]. Furthermore, extensive skill training leads to long-lasting potentiation of glutamatergic inputs into both dMSNs and iMSNs [4]. We report here that, in DLS, both dMSNs and iMSNs are involved in positive reinforcement, but support different action strategies.
Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.
Figures
Figure 1
Optogenetic self-stimulation of striatonigral and striatopallidal DLS neurons supports the reinforcement of different action strategies. (A) Acquisition of lever-pressing for ChR D1-Cre animals (n = 6) and YFP controls (n = 6). (B) Acquisition of lever-pressing for ChR D2-Cre animals (n = 10) and YFP controls (n = 9). (C) Difference in pressing from the first to the last day of training for ChR and YFP D1-Cre, for active and inactive levers. (D) Difference in pressing from the first to the last day of training for ChR and YFP D2-Cre, for active and inactive levers. (E,F) Probability of transition from an active lever press to a subsequent active lever press (versus an inactive press) for (E) ChR D1-Cre and (F) ChR D2-Cre. (G,H) Contingency degradation and reinstatement for (G) D1-Cre and (H) D2-Cre. Mean ± s.e.m. plotted in all graphs; LD: last day of training; CD: contingency degradation day; R: reinstatement day. ∗ denotes p < 0.05.
References
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