School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
Neurosci Lett. 2012 Jan 6;506(1):121-5. doi: 10.1016/j.neulet.2011.10.063. Epub 2011 Nov 2.
Late-phase long-term potentiation (L-LTP) of excitatory synaptic transmission at thalamic input synapses onto the lateral amygdala (T-LA synapses) has been proposed as a cellular substrate for long-term fear memory. This notion is evidenced primarily by previous reports in which the same pharmacological treatments block both T-LA L-LTP and the consolidation of fear memory. In this study, we report that fear conditioning occludes L-LTP at T-LA synapses in brain slices prepared after fear memory consolidation. L-LTP was restored either when synaptic depotentiation was induced prior to L-LTP induction in brain slices prepared from conditioned rats or when brain slices were prepared from conditioned rats that had been exposed to subsequent fear extinction, which is a behavior paradigm known to induce in vivo synaptic depotentiation at T-LA synapses. These results suggest that fear conditioning recruits L-LTP-like mechanisms that are reversible and saturable at T-LA synapses.
晚时程增强（L-LTP）在外侧杏仁核（T-LA）突触的兴奋性突触传递已被提议作为长期恐惧记忆的细胞基础。这一概念主要基于以下先前的报告，其中相同的药理学处理阻断了 T-LA L-LTP 和恐惧记忆的巩固。在这项研究中，我们报告说，在恐惧记忆巩固后制备的脑片中，恐惧条件反射会阻断 T-LA 突触的 L-LTP。当在从条件化大鼠制备的脑片中在 L-LTP 诱导之前诱导突触去极化时，L-LTP 得到恢复，或者当从已经暴露于随后的恐惧消退的条件化大鼠制备脑片时，L-LTP 得到恢复，已知该行为范式在 T-LA 突触处诱导体内突触去极化。这些结果表明，恐惧条件反射招募了可在 T-LA 突触处逆转和饱和的类似 L-LTP 的机制。
