School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
Neurobiol Learn Mem. 2011 Sep;96(2):315-23. doi: 10.1016/j.nlm.2011.06.005. Epub 2011 Jun 13.
The basolateral amygdala (BLA) and medial prefrontal cortex (mPFC) are inter-connected regions involved in fear memory expression. The reciprocal nature of projections between these areas differs along the rostrocaudal extent of BLA. This study investigated the role of functional interactions between BLA and the prelimbic (PL) subregion of mPFC in mediating contextual fear memory. Freezing served as the measure of conditioned fear. Experiments 1-3 examined the effects of left, right or bilateral infusion of bupivacaine into anterior BLA (aBLA), posterior BLA (pBLA) or PL on fear memory expression. Reversible inactivation of left, right or bilateral aBLA impaired fear memory expression. Bilateral inactivation of pBLA or PL also disrupted the expression of fear memory, although left or right inactivation alone had no significant effects in either region. Experiment 4 examined the effects of functionally disconnecting pBLA and PL on contextual fear memory by infusing bupivacaine unilaterally into pBLA and PL in the ipsilateral or contralateral hemisphere. Fear memory expression was impaired by asymmetric inactivation of pBLA and PL; however, a similar effect was also observed with symmetric inactivation of these regions. Bupivacaine infusion did not affect behavior in the open field, likely ruling out non-specific effects of inactivation on innate fear and locomotor activity. These results demonstrate different roles for rostral and caudal BLA in mediating the expression of contextual fear memory. They also raise the possibility that pBLA-PL circuitry is involved in subserving fear memory expression via complex processing mechanisms, although further research is needed to confirm this preliminary finding.
外侧杏仁核（BLA）和内侧前额叶皮层（mPFC）是相互连接的区域，参与恐惧记忆的表达。这些区域之间的投射的相互性质沿着 BLA 的前后延伸而不同。本研究调查了 BLA 与 mPFC 的前额叶（PL）亚区之间的功能相互作用在介导上下文恐惧记忆中的作用。冻结作为条件恐惧的衡量标准。实验 1-3 研究了将布比卡因分别注入前外侧杏仁核（aBLA）、后外侧杏仁核（pBLA）或 PL 对恐惧记忆表达的影响。可逆失活左、右或双侧 aBLA 会损害恐惧记忆的表达。双侧 pBLA 或 PL 的失活也破坏了恐惧记忆的表达，尽管单独失活左或右在这两个区域都没有显著影响。实验 4 通过单侧将布比卡因注入同侧或对侧脑半球的 pBLA 和 PL，研究了功能上分离 pBLA 和 PL 对上下文恐惧记忆的影响。不对称失活 pBLA 和 PL 会损害恐惧记忆的表达；然而，这些区域的对称失活也观察到类似的效果。布比卡因输注不会影响开阔场中的行为，可能排除了失活对先天恐惧和运动活动的非特异性影响。这些结果表明，BLA 的头侧和尾侧在介导上下文恐惧记忆的表达中具有不同的作用。它们还提出了一种可能性，即 pBLA-PL 回路可能通过复杂的处理机制参与恐惧记忆的表达，尽管需要进一步的研究来证实这一初步发现。
