Davis M
Department of Psychiatry, Yale University School of Mcdicine, New Haven, Connecticut, USA.
Biol Psychiatry. 1998 Dec 15;44(12):1239-47. doi: 10.1016/s0006-3223(98)00288-1.
Although there is a close correspondence between fear and anxiety, and the study of fear in animals has been extremely valuable for understanding brain systems that are important for anxiety, it is equally clear that a richer animal model of human anxiety disorders would include measures of both stimulus-specific fear and something less stimulus specific, more akin to anxiety. Studies in patients with posttraumatic stress syndrome indicate these individuals seem to show normal fear reactions but abnormal anxiety measured with the acoustic startle reflex. Studies in rats, also using the startle reflex, indicate that highly processed explicit cue information (lights, tones, touch) activates the central nucleus of the amygdala, which in turn activates hypothalamic and brain stem target areas involved in specific signs of fear. Somewhat less explicit information, such as that produced by exposure to a threating environment for several minutes or by intraventricular administration of the peptide corticotropin-releasing hormone may activate a brain area closely related to the amygdala, called the bed nucleus of the stria terminalis, which in turn activates hypothalamic and brain stem target areas involved in specific signs of fear or anxiety. Because the nature of this information may be less specific than that produced by an explicit cue, and of much longer duration, activation of the bed nucleus of the stria terminalis may be more akin to anxiety than to fear.
尽管恐惧与焦虑之间存在密切关联，并且对动物恐惧的研究对于理解对焦虑至关重要的脑系统极有价值，但同样清楚的是，更丰富的人类焦虑症动物模型将包括特定刺激恐惧的测量以及一些不太具刺激特异性、更类似于焦虑的指标。对创伤后应激综合征患者的研究表明，这些个体似乎表现出正常的恐惧反应，但用听觉惊吓反射测量的焦虑异常。对大鼠的研究，同样使用惊吓反射，表明经过高度处理的明确线索信息（灯光、音调、触摸）会激活杏仁核的中央核，进而激活参与恐惧特定体征的下丘脑和脑干目标区域。不太明确的信息，例如暴露于威胁环境几分钟或脑室内注射肽促肾上腺皮质激素释放激素所产生的信息，可能会激活与杏仁核密切相关的一个脑区，称为终纹床核，它进而激活参与恐惧或焦虑特定体征的下丘脑和脑干目标区域。由于这种信息的性质可能比明确线索产生的信息更不具特异性，且持续时间长得多，终纹床核的激活可能更类似于焦虑而非恐惧。
