Akagi Jordão Elisa Mari, Onishi Barbara Kazue Amaral, Xavier Gilberto Fernando
Department of Physiology, Biosciences Institute, University of São Paulo, São Paulo, SP, Brasil.
PLoS One. 2015 Apr 30;10(4):e0125489. doi: 10.1371/journal.pone.0125489. eCollection 2015.
The basolateral amygdala complex (BLA), including the lateral (LA), basal (BA) and accessory basal (AB) nuclei, is involved in acquisition of contextual and auditory fear conditioning. The BA is one of the main targets for hippocampal information, a brain structure critical for contextual learning, which integrates several discrete stimuli into a single configural representation. Congruent with the hodology, selective neurotoxic damage to the BA results in impairments in contextual, but not auditory, fear conditioning, similarly to the behavioral impairments found after hippocampal damage. This study evaluated the effects of muscimol-induced reversible inactivation of the BA during a simultaneous contextual and auditory fear conditioning training on later fear responses to both the context and the tone, tested separately, without muscimol administration. As compared to control rats micro-infused with vehicle, subjects micro-infused with muscimol before training exhibited, during testing without muscimol, significant reduction of freezing responses to the conditioned context, but not to the conditioned tone. Therefore, reversible inactivation of the BA during training impaired contextual, but not auditory fear conditioning, thus confirming and extending similar behavioral observations following selective neurotoxic damage to the BA and, in addition, revealing that this effect is not related to the lack of a functional BA during testing.
基底外侧杏仁核复合体（BLA），包括外侧核（LA）、基底核（BA）和副基底核（AB），参与情境性和听觉恐惧条件反射的习得。BA是海马体信息的主要靶点之一，海马体是一种对情境学习至关重要的脑结构，它将几个离散的刺激整合为一个单一的构型表征。与神经传导路径一致，对BA进行选择性神经毒性损伤会导致情境性恐惧条件反射受损，但不会导致听觉恐惧条件反射受损，这与海马体损伤后发现的行为损伤类似。本研究评估了在同时进行情境性和听觉恐惧条件反射训练期间，毒蝇蕈醇诱导的BA可逆性失活对随后分别测试的对情境和音调的恐惧反应的影响，测试时不给予毒蝇蕈醇。与微量注入赋形剂的对照大鼠相比，在训练前微量注入毒蝇蕈醇的大鼠在不使用毒蝇蕈醇的测试期间，对条件化情境的僵住反应显著降低，但对条件化音调的僵住反应没有降低。因此，训练期间BA的可逆性失活损害了情境性恐惧条件反射，但没有损害听觉恐惧条件反射，从而证实并扩展了对BA进行选择性神经毒性损伤后的类似行为观察结果，此外，还揭示了这种效应与测试期间BA功能缺失无关。
