The fear circuit revisited: contributions of the basal amygdala nuclei to conditioned fear.
The fear circuit revisited: contributions of the basal amygdala nuclei to conditioned fear.
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DOI：
10.1523/jneurosci.3410-11.2011
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发表时间：
2011-10-26
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影响因子：
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通讯作者：
Paré D
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文献类型：
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作者：
Amano T;Duvarci S;Popa D;Paré D
外侧核（LA）是杏仁核的条件刺激（CS）信息输入站，而中央核内侧区（CeM）是杏仁核向脑干恐惧效应器投射的输出区。然而，LA和CEM之间没有直接联系。作为LA的主要靶点，基底内侧杏仁核（BM）对CeM有很强的投射，是弥合这一差距的良好候选者。与这一概念相一致，据报道，基底核（BM+基底外侧-BL-核）的组合训练后病变消除了条件性恐惧反应，而选择性BL失活则没有。因此，我们研究了BM和BL的相对贡献条件性恐惧使用单位记录和失活蝇蕈醇微量输注大鼠。大约30%的BM和BL神经元获得了强大的响应听觉CS预测脚电击。虽然大多数BL细胞在CS偏移时停止放电，但BM反应通常比CS持续≥ 40 s，与CS后条件性恐惧的持续性平行。这一观察结果表明，BM神经元不是被动中继的快速适应LA输入的CS。令人惊讶的是，BM或BL与蝇蕈醇的独立失活并没有导致条件冻结的减少，即使第二天看到了灭绝回忆缺陷。相反，组合BL-BM失活。总的来说，这些结果支持的概念，基底核参与条件性恐惧的表达和消退，但它们之间存在功能冗余。
The lateral nucleus (LA) is the input station of the amygdala for information about conditioned stimuli (CS), whereas the medial sector of the central nucleus (CeM) is the output region that contributes most amygdala projections to brainstem fear effectors. However, there are no direct links between LA and CeM. As the main target of LA and with its strong projection to CeM, the basomedial amygdala (BM) constitutes a good candidate to bridge this gap. Consistent with this notion, it was reported that combined post-training lesions of the basal nuclei (BM plus basolateral -BL- nucleus) abolish conditioned fear responses whereas selective BL inactivation does not. Thus, we examined the relative contribution of BM and BL to conditioned fear using unit recordings and inactivation with muscimol micro-infusions in rats. Around 30% of BM and BL neurons acquired robust responses to auditory CSs predicting footshocks. While most BL cells stopped firing at CS offset, BM responses typically outlasted the CS by ≥40s, paralleling the persistence of conditioned fear after the CS. This observation suggests that BM neurons are not passive relays of rapidly adapting LA inputs about the CS. Surprisingly, independent inactivation of either BM or BL with muscimol did not cause a reduction of conditioned freezing even though an extinction recall deficit was seen the next day. In contrast, combined BL–BM inactivation did. Overall, there results support the notion that the basal nuclei are involved in conditioned fear expression and extinction but that there is functional redundancy between them.