Oades R D, Rivet J M, Taghzouti K, Kharouby M, Simon H, Le Moal M
Brain Res. 1987 Mar 17;406(1-2):136-46. doi: 10.1016/0006-8993(87)90778-5.
The performance of rats on the conditioned blocking test of learned inattention was measured in a two-way shuttle avoidance task after sham and dopamine (DA)-depleting lesions of the frontal cortex, septum and ventral tegmental area (VTA). Animals were trained on two sessions with tone and/or light as conditioned stimuli. One group was trained with both stimuli on both sessions. A second group was trained on the first session with one stimulus and on the second with both stimuli. The blocking of conditioning to the added stimulus (b) was tested by presenting the stimuli (a and b) separately and measuring the blocking ratio (avoidance to b/a + b) and response latencies. No deficits were recorded on tests of sensory and motor ability. The VTA group alone showed a hyperlocomotor response to apomorphine treatment and did not acquire the avoidance response. The appearance of blocking in the septal group was delayed until the end of the test session. Blocking was mildly attenuated in the frontal group. DA levels were depleted by about 80% and noradrenaline (NA) levels by, respectively, 20 and 50% in frontal and septal areas. This suggests that the level of DA activity or the balance between the activity of DA and NA in frontal and limbic regions can contribute to efficient associative conditioning and/or the normal ability of rats not to attend to a redundant stimulus.
在对额叶皮质、隔区和腹侧被盖区（VTA）进行假手术和多巴胺（DA）耗竭性损伤后，通过双向穿梭回避任务测量大鼠在习得性注意力条件性阻断测试中的表现。动物在两个阶段接受以音调或/和光线作为条件刺激的训练。一组在两个阶段都接受两种刺激的训练。第二组在第一阶段接受一种刺激的训练，在第二阶段接受两种刺激的训练。通过分别呈现刺激（a和b）并测量阻断率（对b/a + b的回避）和反应潜伏期，来测试对添加刺激（b）的条件反射阻断情况。在感觉和运动能力测试中未记录到缺陷。单独的VTA组对阿扑吗啡治疗表现出运动亢进反应，且未习得回避反应。隔区组的阻断现象出现延迟，直到测试阶段结束。额叶组的阻断现象略有减弱。额叶和隔区的DA水平分别降低了约80%，去甲肾上腺素（NA）水平分别降低了20%和50%。这表明额叶和边缘区域的DA活性水平或DA与NA活性之间的平衡，可能有助于大鼠进行有效的联想性条件反射和/或正常情况下不关注冗余刺激的能力。
