Bohn Ines, Giertler Christian, Hauber Wolfgang
Abteilung Tierphysiologie, Biologisches Institut, Universität Stuttgart, D-70550, Stuttgart, Germany.
Behav Brain Res. 2003 Jul 14;143(1):49-56. doi: 10.1016/s0166-4328(03)00008-1.
The orbital prefrontal cortex (OPFC) is suggested to be part of a circuitry mediating the perception of reward and the initiation of adaptive behavioural responses. In the present study, we investigated in rats changes of goal-directed behaviour after bilateral OPFC-lesions by N-methyl-D-aspartate (NMDA) in more detail. A reaction time (RT) task was used which is sensitive to subtle changes in discriminative guidance of instrumental behaviour by the anticipated reward magnitudes. The task demands conditioned lever release triggered by an imperative stimulus. The upcoming reward magnitude (five or one food pellet) for each trial was randomly chosen and signalled in advance by distinct instructive stimuli. In trained rats, RTs of instrumental responses were determined by the two distinct stimulus-reward magnitude contingencies, i.e. RTs were shorter to the instructive stimulus predictive of the higher reward magnitude. Results show that lesions of the OPFC did not impair discriminative guidance of behavioural responses according to preoperatively acquired stimulus-reward magnitude contingencies. However, guidance of instrumental behaviour was altered in lesioned rats after a reversal of the stimulus-reward magnitude contingencies. The data add further support to the hypothesis that the rat OPFC is not involved in retrieval of acquired stimulus-reward magnitude contingencies but in integration of incentive information to guide behaviour after a reversal of stimulus-reward contingencies.
眶额前皮质（OPFC）被认为是介导奖励感知和适应性行为反应启动的神经回路的一部分。在本研究中，我们更详细地研究了大鼠双侧OPFC被N - 甲基 - D - 天冬氨酸（NMDA）损伤后目标导向行为的变化。使用了一种反应时间（RT）任务，该任务对预期奖励大小对工具性动作辨别性引导的细微变化敏感。该任务要求由命令性刺激触发条件性杠杆释放。每次试验即将到来的奖励大小（五个或一个食物颗粒）是随机选择的，并通过不同的指示性刺激预先发出信号。在经过训练的大鼠中，工具性反应的反应时间由两种不同的刺激 - 奖励大小偶然性决定，即对预测更高奖励大小的指示性刺激的反应时间更短。结果表明，OPFC损伤并未损害根据术前获得的刺激 - 奖励大小偶然性对行为反应的辨别性引导。然而，在刺激 - 奖励大小偶然性反转后，损伤大鼠的工具性动作引导发生了改变。这些数据进一步支持了以下假设：大鼠OPFC不参与获取的刺激 - 奖励大小偶然性的检索，而是参与刺激 - 奖励偶然性反转后引导行为的激励信息整合。
