NEURAL MECHANISMS OF MOTIVATION AND REWARD

为了量化猴子的动机状态，我们开发了一种行为 猴子面临同样的任务要求， 但对工作量的预期不同 需要获得果汁奖励 在每次试验中，猴子都必须 手动地响应在视觉刺激的颜色的变化， 视频监控中心。 一种改进的变比钢筋 使用进度表，其中通过以下方式指示获得奖励的进度 位于所述颜色刺激物上方的第二视觉提示。 猴子的 准确性和延迟随着奖励时间的增加而显著提高， closer. 由于行为需求保持不变， 业绩似乎反映了积极性的提高。 当一只猴子 给予静脉注射可卡因作为奖励而不是果汁，暗示的效果 动物获得奖励的过程被打乱了。 这种范式 将被用于研究直接在有关神经元的活动， 腹侧纹状体和相关结构的动机水平， 果汁或可卡因奖励。

To quantify motivational state in monkeys, we have developed a behavioral paradigm in which monkeys are faced with the same task demands from trial to trial but with different expectancies regarding the amount of work needed to earn a juice reward. On each trial, the monkey is required to respond manually to a change in the color of a visual stimulus in the center of a video monitor. A modified variable-ratio reinforcement schedule is used in which progress toward earning a reward is indicated by a second visual cue located above the color stimulus. The monkey's accuracy and latency improve dramatically as the time of reward gets closer. Since the behavioral demands remain constant, the improvement in performance appears to reflect increased motivation. When a monkey was given intravenous cocaine for reward instead of juice, the effect of cueing the animal's progress toward earning a reward was disrupted. This paradigm will be used in studies directed at relating the activity of neurons in the ventral striatum and associated structures to levels of motivation for juice or cocaine reward.