The Dorsolateral Striatum Competes with Visual Discrimination Learning

Monday, September 22, 2014 — Poster Session I
12:00 p.m. – 2:00 p.m.	FAES Academic Center	NIAAA	NEURO-4

* FARE Award Winner

Authors

• H.C. Bergstrom
• C.L. Pickens
• C.R. Pinard
• O. Bukalo
• L.R. Halladay
• A. Holmes

Abstract

Brain processes of reward learning are essential for shaping and guiding decision-making. The dorsolateral striatum (DLS) is required for mediating various forms of reward learning but precisely how the DLS contributes to reward learning, and which of the various components of reward learning it mediates is unknown. Here we investigated DLS-mediated reward learning using optogenetic tools in vivo in combination with a touchscreen visual discrimination task. Prior to learning, a viral construct (rAAV8/CAG-ArchT-GFP) was expressed in the DLS of C57BL/6J mice. We found DLS inhibition at the time when mice made a response facilitated the rate of learning, as compared to a control group expressing an inactive virus (rAAV8/CAG-GFP). This surprising result demonstrates that the DLS interferes with reward learning (stimulus-response) associations. Facilitation of learning was already evident at the first (of multiple) training sessions, suggesting the DLS engages reward-learning processes at its earliest stages. By contrast, DLS inhibition at the time when mice collected the reward did not impact performance, indicating the DLS does not process (at least not directly) response outcome signals (reward receipt). Overall, these findings support a dynamic model of DLS-mediated functioning in which the DLS competes with stimulus-response relationships at the earliest stages of learning.

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