Stern C E, Passingham R E
Department of Experimental Psychology, University of Oxford, UK.
Exp Brain Res. 1995;106(2):239-47. doi: 10.1007/BF00241119.
The nucleus accumbens (NA), which receives inputs from limbic structures and projects to the motor system, may be important for the association of reinforcement with action. There are projections to the NA from the amygdala and hippocampus. Discrimination and reversal learning tasks which are known to be disrupted by lesions to these areas in monkeys were given to monkeys with lesions of the NA. Twelve monkeys (Macaca fascicularis) were used in the present study. Six of these received ibotenic acid lesions which resulted in considerable cell loss in the NA; the remaining six acted as controls. The first group of six monkeys were taught a visual discrimination task pre-operatively. Post-operatively, these monkeys were tested on visual and spatial discrimination and reversal tasks. A second group of six monkeys were tested on a motor reversal task. The results indicate that ibotenic acid lesions of the NA transiently impair spatial but not visual reversal learning in monkeys. The NA lesions did not impair a monkey's ability to perform visual or spatial discriminations, or the ability to perform the motor learning or motor reversal tasks. Our results suggest that bilateral lesions of the NA in monkeys do not disrupt the ability to discriminate basic properties of reward-related stimuli or the formation of visual stimulus-reward associations. In addition, our results argue against theories which suggest that the NA is important for behavioural switching or general behavioural flexibility. We conclude that the NA may play a more specific role in the association of temporal and spatial cues with movement and reward.
伏隔核（NA）接收来自边缘系统结构的输入并投射到运动系统，可能在强化与动作的关联中起重要作用。杏仁核和海马体有向伏隔核的投射。对患有伏隔核损伤的猴子进行了辨别和逆向学习任务，已知这些任务会因猴子这些区域的损伤而受到干扰。本研究使用了12只猕猴（食蟹猴）。其中6只接受了鹅膏蕈氨酸损伤，导致伏隔核中大量细胞丢失；其余6只作为对照。第一组6只猴子在术前被教导视觉辨别任务。术后，对这些猴子进行视觉和空间辨别及逆向任务测试。第二组6只猴子接受运动逆向任务测试。结果表明，伏隔核的鹅膏蕈氨酸损伤会暂时损害猴子的空间而非视觉逆向学习能力。伏隔核损伤并未损害猴子执行视觉或空间辨别的能力，也未损害其执行运动学习或运动逆向任务的能力。我们的结果表明，猴子双侧伏隔核损伤不会破坏辨别与奖励相关刺激的基本属性或形成视觉刺激 - 奖励关联的能力。此外，我们的结果与认为伏隔核在行为转换或一般行为灵活性方面很重要的理论相悖。我们得出结论，伏隔核可能在时间和空间线索与运动及奖励的关联中发挥更具体的作用。
