Shi C, Davis M
Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06508, USA.
J Neurosci. 1999 Jan 1;19(1):420-30. doi: 10.1523/JNEUROSCI.19-01-00420.1999.
It is well established that the basolateral amygdala is critically involved in the association between an unconditioned stimulus (US), such as a foot shock, and a conditioned stimulus (CS), such as a light, during classic fear conditioning. However, little is known about how the US (pain) inputs are relayed to the basolateral amygdala. The present studies were designed to define potential US pathways to the amygdala using lesion methods. Electrolytic lesions before or after training were placed in caudal granular/dysgranular insular cortex (IC) alone or in conjunction with the posterior intralaminar nuclei of the thalamus (PoT/PIL), and the effects on fear conditioning were examined. Pretraining lesions of both IC and PoT/PIL, but not lesions of IC alone, blocked the acquisition of fear-potentiated startle. However, post-training combined lesions of IC and PoT/PIL did not prevent expression of conditioned fear. Given that previous studies have shown that lesions of PoT/PIL alone had no effect on acquisition of conditioned fear, these results suggest that two parallel cortical (insula-amygdala) and subcortical (PoT/PIL-amygdala) pathways are involved in relaying shock information to the basolateral amygdala during fear conditioning.
众所周知，在经典恐惧条件反射过程中，基底外侧杏仁核在诸如足部电击等无条件刺激（US）与诸如灯光等条件刺激（CS）之间的关联中起着关键作用。然而，关于US（疼痛）输入如何传递到基底外侧杏仁核却知之甚少。本研究旨在使用损伤方法确定通向杏仁核的潜在US通路。在训练前或训练后，单独或与丘脑后内侧核（PoT/PIL）联合，在尾侧颗粒/颗粒下岛叶皮质（IC）进行电解损伤，并检查对恐惧条件反射的影响。IC和PoT/PIL的训练前损伤，但不是单独的IC损伤，阻断了恐惧增强惊吓的获得。然而，训练后IC和PoT/PIL的联合损伤并未阻止条件性恐惧的表达。鉴于先前的研究表明，单独的PoT/PIL损伤对条件性恐惧的获得没有影响，这些结果表明，在恐惧条件反射过程中，两条平行的皮质（岛叶-杏仁核）和皮质下（PoT/PIL-杏仁核）通路参与了将电击信息传递到基底外侧杏仁核。
