Bidirectional synaptic plasticity in intercalated amygdala neurons and the extinction of conditioned fear responses
Bidirectional synaptic plasticity in intercalated amygdala neurons and the extinction of conditioned fear responses
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DOI：
10.1016/s0306-4522(02)00455-4
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发表时间：
2002-01-01
期刊：
影响因子：
3.3
通讯作者：
Paré, D
中科院分区：
文献类型：
--
作者：
Royer, S;Paré, D
经典的恐惧调节被认为是基底外侧杏仁核中条件性突触输入增强的结果。那是。条件刺激会激发中央核中的更多神经元，并通过它们投射到脑干和下丘脑。然而，会引起恐惧反应。许多数据表明，恐惧反应的消失并不取决于这些变化的逆转，而是取决于与第一个变化竞争的并行的 NMDA 依赖性学习。因为它们控制从基底外侧杏仁核到中央核的冲动交通。闰细胞团的 GABA 能神经元处于执行第二次学习的理想位置。与这个假设一致。目前的研究表明，基底外侧传入神经的低频和高频刺激分别诱导闰细胞反应的长期抑制（LTD）和增强（LTP）。此外，通过应用NMDA拮抗剂来诱导LTP和LTD。确定这些活动依赖性变化是如何表达的。我们测试了 LTD 和 LTP 诱导是否与配对脉冲促进的修改有关。发射机释放概率的指数。只有 LTP 诱导与配对脉冲促进的变化相关，先前增强的突触的去电位不会恢复配对脉冲促进的修改。表明 LTP 与突触前改变有关。但LTD和去势取决于突触后的变化。综合起来。我们的结果表明，嵌入神经元上的基底外侧突触可以表达 NMDA 依赖性 LTP 和 LTD。与嵌入神经元是条件性恐惧反应消除的可塑性关键位点的可能性一致，最终，这些可塑性事件可能会呈现来自中央核兴奋性神经元的条件性杏仁核反应，从而引发条件性恐惧反应。 (C) 2002 国际广播组织。由爱思唯尔科学有限公司出版。保留所有权利。
Classical fear conditioning is believed to result from potentiation of conditioned synaptic inputs in the basolateral amygdala. That is. the conditioned stimulus would excite more neurons in the central nucleus and, via their projections to the brainstem and hypothalamus. evoke fear responses, However. much data suggests that extinction of fear responses does not depend on the reversal of these changes but on a parallel NMDA-dependent learning that competes with the first one. Because they control impulse traffic from the basolateral amygdala to the central nucleus. GABAergic neurons of the intercalated cell masses are ideally located to implement this second learning. Consistent with this hypothesis. the present study reserved shows that low- and high-frequency stimulation of basolateral afferents respectively induce long-term depression (LTD) and potentiation (LTP) of responses in intercalated cells. Moreover, induction of LTP and LTD is presented by application of an NMDA antagonist. To determine how these activity-dependent changes are expressed. we tested whether LTD and LTP induction are associated with modifications in paired-pulse facilitation. an index of transmitter release probability. Only LTP induction was associated with a change in paired-pulse facilitation, Depotentiation of previously potentiated synapses did not revert the modification in paired pulse facilitation. suggesting that LTP is associated with presynaptic alterations. but that LTD and depotentiation depend on postsynaptic changes.Taken together. our results suggest that basolateral synapses onto intercalated neurons can express NMDA-dependent LTP and LTD. consistent with the possibility that intercalated neurons are a critical locus of plasticity for the extinction of conditioned fear responses, Ultimately, these plastic events may present conditioned amygdala responses from exciting neurons of the central nucleus, and thus from evoking conditioned fear responses. (C) 2002 IBRO. Published by Elsevier Science Ltd. All rights reserved.