本研究使用抑制性逃避學習作業來探討前扣帶皮質 (ACC) 和內側視丘(MT)在恐懼學習中 所扮演的角色。實驗一結果顯示 ACC 的破壞，能影響抑制性逃避學習的短期記憶，而不會 影響其長期記憶的提取。ACC 的破壞並不會影響到動物對電刺激表現出來的反射動作及運 動功能。暫時性阻斷的研究顯示，在動物學習完成之後，即刻注射利多咽(lidocaine)到 ACC，會干擾對此學習的短期記憶。另外一方，MT 的破壞，會同時損害抑制性逃避學習的 短期和長期記憶。在動物學習完成之後，即刻注射利多咽到 MT，會干擾對此學習的短期記 憶。然而如果在動物在抑制性逃避學習完成後，即 24 小時的回憶作業前注射利多咽到 MT 作業並不會影響記憶。此研究結果顯示 ACC 在短期，而非長期的抑制性逃避學習扮演的重 要的角色，而 MT 在則在這類學習的穩固化時有一定的重要性。 The anterior cingulate cortex (ACC) and the medial thalamus (MT) are two of the main components of the medial pain pathway that subserve the affective aspect of the pain experience. The hypothesis of this study is that the ACC is involved in short-term aversive information processing and that the MT is critical to the encoding of unconditioned nociceptive information. The role of these two components in short-term and long-term aversive information processing was investigated by using a step-through inhibitory avoidance task. Behavioral training began one week after brain surgery of the ACC or the MT. The retention tests were given 30 s (short-term) or 24 h (long-term) after training. Firstly, it was shown that pre-training radiofrequency lesions of the ACC impaired the 30 s, but not the 24 h retention test. Microinfusions of lidocaine into the ACC immediately after training impaired the retention test given 10 min later. Secondly, it was shown that pre-training radiofrequency lesions of the MT blocked both the 30 s and the 24 h retention test. However, post-training, but not pre-testing, microinfusions of lidocaine into MT blocked the 24 h retention test. These results suggest that the ACC may play an important role in the nociceptive short-term, but not long-term, information processing. In contrast, MT is possibly important for the consolidation of nociceptive information storage.
