Chudasama Yogita, Wright Katherine S, Murray Elisabeth A
Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.
Biol Psychiatry. 2008 Jun 1;63(11):1084-91. doi: 10.1016/j.biopsych.2007.11.012. Epub 2008 Jan 11.
Although the role of the hippocampus in emotional behavior has long been recognized, the extent to which the hippocampus plays a role in the regulation and expression of emotion in rhesus monkeys has not been systematically explored.
Rhesus monkeys (Macaca mulatta) with excitotoxic lesions of the hippocampal formation and unoperated control animals were assessed on two different types of emotional processing: defensive reactions to a potential predator (experiment 1) and ability to update the value of positive reinforcers, in this case food (experiment 2). Monkeys with aspiration lesions of the perirhinal cortex were also included in this study as an operated control group.
In experiment 1, whereas both operated groups showed reduced latencies to retrieve food located near an innately fear-provoking stimulus, a fake snake, only monkeys with hippocampal lesions displayed reduced defensive reactions to the snake. In experiment 2, both operated groups performed as well as control animals when choosing objects flexibly based on the current value of a food.
These findings dissociate the hippocampus and perirhinal cortex in fear expression and specifically implicate the hippocampal formation in generating responses to stimuli that are potentially threatening.
尽管海马体在情绪行为中的作用早已得到认可，但海马体在恒河猴情绪调节和表达中所起作用的程度尚未得到系统研究。
对海马结构有兴奋性毒性损伤的恒河猴（猕猴）和未手术的对照动物进行了两种不同类型的情绪处理评估：对潜在捕食者的防御反应（实验1）以及更新正强化物（在此为食物）价值的能力（实验2）。本研究还纳入了海马旁皮质有抽吸损伤的猴子作为手术对照组。
在实验1中，虽然两个手术组在获取位于天生引发恐惧的刺激物（一条假蛇）附近的食物时潜伏期均缩短，但只有海马体损伤的猴子对蛇的防御反应减弱。在实验2中，当根据食物的当前价值灵活选择物体时，两个手术组的表现与对照动物相当。
这些发现区分了海马体和海马旁皮质在恐惧表达中的作用，并特别表明海马结构在对潜在威胁刺激产生反应中起作用。
