Dopamine D2R Upregulation in Ventral Striatopallidal Neurons Does Not Affect Pavlovian or Go/No-Go Learning

• Published in: Behavioral neuroscience 2021-06, Vol.135 (3), p.369-379
• Main Authors: Martyniuk, Kelly M., Dandeneau, Michelle, Balsam, Peter D., Kellendonk, Christoph
• Format: Article
• Language: English
• Subjects: Animal; Animal Learning; Associative learning; Auditory discrimination learning; Basal Ganglia; Classical Conditioning; Dopamine; Dopamine D1 receptors; Dopamine D2 receptors; Extinction (Learning); Female; Go/no-go discrimination learning; Hyperactivity; Learning; Male; Mice; Motivation; Neostriatum; Neural Receptors; Neurons; Observational learning; Operant conditioning; Pallidum (ventral); Reinforcement; Reward Learning; Rewards; Synaptic transmission; Up-regulation
• ISSN: 0735-7044; 1939-0084
• DOI: 10.1037/bne0000403

Ventral striatal dopamine is thought to be important for associative learning. Dopamine exerts its role via activation of dopamine D1 and D2 receptors in the ventral striatum. Upregulation of dopamine D2R in ventral striatopallidal neurons impairs incentive motivation via inhibiting synaptic transmission to the ventral pallidum. Here, we determined whether upregulation of D2Rs and the resulting impairment in ventral striatopallidal pathway function modulates associative learning in an auditory Pavlovian reward learning task as well as Go/No-Go learning in an operant based reward driven Go/No-Go task. We found that upregulation of D2Rs did not affect Pavlovian learning or the extinction of Pavlovian responses, and neither did it alter No-Go learning. We however observed a delay in the Go component of the task which may indicate a deficit in learning though it could also be attributed to the established locomotor hyperactivity of the mice. In combination with previously published findings, our data suggest that D2Rs in ventral striatopallidal neurons play a specific role in regulating motivation by balancing cost/benefit computations but do not necessarily affect associative learning.