Department of Psychology, University of York, Heslington, York, YO10 5DD, UK.
Psychopharmacology (Berl). 2010 Jun;210(3):303-16. doi: 10.1007/s00213-010-1813-z. Epub 2010 Apr 20.
Amygdala dopamine is crucially involved in the acquisition of Pavlovian associations, as measured via conditioned approach to the location of the unconditioned stimulus (US). However, learning begins before skeletomotor output, so this study assessed whether amygdala dopamine is also involved in earlier 'emotional' learning.
A variant of the conditioned reinforcement (CR) procedure was validated where training was restricted to curtail the development of selective conditioned approach to the US location, and effects of amygdala dopamine manipulations before training or later CR testing assessed.
Experiment 1a presented a light paired (CS+ group) or unpaired (CS- group) with a US. There were 1, 2 or 10 sessions, 4 trials per session. Then, the US was removed, and two novel levers presented. One lever (CR+) presented the light, and lever pressing was recorded. Experiment 1b also included a tone stimulus. Experiment 2 applied intra-amygdala R(+) 7-OH-DPAT (10 nmol/1.0 microl/side) before two training sessions (Experiment 2a) or a CR session (Experiment 2b).
For Experiments 1a and 1b, the CS+ group preferred the CR+ lever across all sessions. Conditioned alcove approach during 1 or 2 training sessions or associated CR tests was low and nonspecific. In Experiment 2a, R(+) 7-OH-DPAT before training greatly diminished lever pressing during a subsequent CR test, preferentially on the CR+ lever. For Experiment 2b, R(+) 7-OH-DPAT infusions before the CR test also reduced lever pressing.
Manipulations of amygdala dopamine impact the earliest stage of learning in which emotional reactions may be most prevalent.
杏仁核多巴胺在获得条件性关联方面起着至关重要的作用，这可以通过条件性接近无条件刺激 (US) 的位置来衡量。然而，学习始于运动输出之前，因此本研究评估了杏仁核多巴胺是否也参与了更早的“情感”学习。
验证了条件性强化 (CR) 程序的一种变体，其中训练受到限制，以遏制对 US 位置的选择性条件性接近的发展，并评估了训练前或稍后的 CR 测试中杏仁核多巴胺的影响。
实验 1a 呈现了一个光配对 (CS+) 或未配对 (CS-) 与 US。有 1、2 或 10 个会话，每个会话 4 次试验。然后，去除 US，并呈现两个新的杠杆。一个杠杆 (CR+) 呈现光，并且记录杠杆按压。实验 1b 还包括一个音调刺激。实验 2 在两个训练会话 (实验 2a) 或 CR 会话 (实验 2b) 之前，应用内侧杏仁核 R(+) 7-OH-DPAT（10 nmol/1.0 微升/侧）。
对于实验 1a 和 1b，CS+ 组在所有会话中都更喜欢 CR+ 杠杆。在 1 或 2 个训练会话期间或相关的 CR 测试期间，条件性洞穴接近是低的且非特异性的。在实验 2a 中，训练前的 R(+) 7-OH-DPAT 大大减少了随后的 CR 测试中的杠杆按压，优先在 CR+ 杠杆上。对于实验 2b，CR 测试前的 R(+) 7-OH-DPAT 也减少了杠杆按压。
杏仁核多巴胺的操作影响了学习的最早阶段，在这个阶段，情感反应可能最为普遍。
