Meunier Martine, Cirilli Laetitia, Bachevalier Jocelyne
Institut des Neurosciences Cognitives de la Méditerranée, Unité Mixte de Recherche 6193, Centre National de la Recherche Scientifique and Aix-Marseille Université, 13602 Marseille, France.
J Neurosci. 2006 Jul 19;26(29):7718-22. doi: 10.1523/JNEUROSCI.1949-06.2006.
Recent efforts to define the functions of the primate rhinal (entorhinal and perirhinal) cortical areas have focused on their interaction with the hippocampus in the mediation of normal memory. Less is known on the functional meaning of their strong connections to the amygdala, a key substrate for emotion. A previous study (Meunier and Bachevalier, 2002) showed evidence that complete rhinal ablations yield changes in monkeys' behavioral responses to affectively salient stimuli. Here, we studied monkeys with separate entorhinal or perirhinal ablations in the same paradigm, where responses were triggered by four stimuli: an unfamiliar human, a conspecific stimulus, a toy snake, and a familiar (generally rewarded) junk object. The two separate lesions produced similar changes, and each replicated the effects of complete rhinal lesions (i.e., attenuated affiliation and enhanced defense). Failure to modulate responses based on previous experience (i.e., memory difficulties) may explain these affective changes. This interpretation does not account, however, for the sparing of some memory-dependent modulations of defense, nor for the lack of correlation between the animals' affective changes and their own recognition memory performance. Alternatively, rhinal damage may introduce a negative bias in the risk assessment of affectively salient stimuli, a proposal more compatible with Gray and McNaughton's (2000) anxiety-centered view of medial temporal functions, than with prominent mnemonic/perceptual functional models of the hippocampal/rhinal duo. Reconciling the two perspectives may improve our understanding of rhinal functions.
近期确定灵长类动物嗅周皮质区域（内嗅皮质和嗅周皮质）功能的研究工作主要聚焦于它们在正常记忆调节过程中与海马体的相互作用。对于它们与杏仁核（情绪的关键基质）的紧密连接所具有的功能意义，我们了解得较少。之前的一项研究（Meunier和Bachevalier，2002年）表明，有证据显示完全切除嗅周皮质会使猴子对情感显著刺激的行为反应发生变化。在此，我们在同一实验范式下研究了分别切除内嗅皮质或嗅周皮质的猴子，实验中的反应由四种刺激引发：一个不熟悉的人、一个同种刺激、一条玩具蛇和一个熟悉的（通常会带来奖励的）废旧物品。这两种单独的损伤产生了相似的变化，并且每种损伤都重现了完全切除嗅周皮质的效果（即情感联系减弱和防御增强）。基于先前经验无法调节反应（即记忆困难）可能解释了这些情感变化。然而，这种解释既无法说明某些依赖记忆的防御调节得以保留的原因，也无法解释动物的情感变化与其自身识别记忆表现之间缺乏相关性的问题。另外，嗅周皮质损伤可能会在对情感显著刺激的风险评估中引入负面偏差，这一观点比海马体/嗅周皮质二元组的突出记忆/感知功能模型更符合Gray和McNaughton（2000年）以焦虑为中心的内侧颞叶功能观点。调和这两种观点可能会增进我们对嗅周皮质功能的理解。
