Rau Vinuta, DeCola Joseph P, Fanselow Michael S
Department of Psychology, University of California, Los Angeles, 415 Hilgard Ave, Los Angeles, CA 90095-1563, USA.
Neurosci Biobehav Rev. 2005;29(8):1207-23. doi: 10.1016/j.neubiorev.2005.04.010. Epub 2005 Aug 10.
Fear is an adaptive response that initiates defensive behavior to protect animals and humans from danger. However, anxiety disorders, such as Posttraumatic Stress Disorder (PTSD), can occur when fear is inappropriately regulated. Fear conditioning can be used to study aspects of PTSD, and we have developed a model in which pre-exposure to a stressor of repeated footshock enhances conditional fear responding to a single context-shock pairing. The experiments in this chapter address interpretations of this effect including generalization and summation or fear, inflation, and altered pain sensitivity. The results of these experiments lead to the conclusion that pre-exposure to shock sensitizes conditional fear responding to similar less intense stressors. This sensitization effect resists exposure therapy (extinction) and amnestic (NMDA antagonist) treatment. The pattern predicts why in PTSD patients, mild stressors cause reactions more appropriate for the original traumatic stressor and why new fears are so readily formed in these patients. This model can facilitate the study of neurobiological mechanisms underlying sensitization of responses observed in PTSD.
恐惧是一种适应性反应，它引发防御行为以保护动物和人类免受危险。然而，当恐惧调节不当时，可能会出现焦虑症，如创伤后应激障碍（PTSD）。恐惧条件反射可用于研究PTSD的各个方面，我们已经开发出一种模型，其中预先暴露于重复电击的应激源会增强对单一情境 - 电击配对的条件性恐惧反应。本章中的实验探讨了这种效应的解释，包括泛化、恐惧的总和或增强、痛觉过敏以及疼痛敏感性的改变。这些实验结果得出结论，预先暴露于电击会使对类似强度较低的应激源的条件性恐惧反应敏感化。这种敏感化效应抵抗暴露疗法（消退）和遗忘（NMDA拮抗剂）治疗。这种模式预测了为什么在PTSD患者中，轻度应激源会引发更适合原始创伤应激源的反应，以及为什么这些患者很容易形成新的恐惧。该模型有助于研究PTSD中观察到的反应敏感化背后的神经生物学机制。
