Sotty F, Sandner G, Gosselin O
Laboratoire de Psychopathologie et Pharmacologie de la Cognition, Unité 405 de l'INSERM, Faculté de Médecine, Strasbourg, France.
Brain Res. 1996 Oct 21;737(1-2):243-54. doi: 10.1016/0006-8993(96)00737-8.
Latent inhibition refers to the fact that the formation of a conditioned association between a conditioned and an unconditioned stimulus is delayed by prior exposure to the conditioned stimulus. Latent inhibition is often investigated in the context of the conditioned emotional response, in which a tone serves as the conditioned and a footshock as the unconditioned stimulus. Such a paradigm was used for the present experiments in which some rats had been pre-exposed to the tone. Two hours after a subsequent exposure to the tone, c-fos immunocytochemistry was used to map activated brain areas. The density of immunoreactive neurones was measured in brain areas involved in audition, fear, stress and memory. For the basic conditioning group, pre-exposure to the tone decreased the density of labelled cells in the auditory system, areas involved in fear and stress and a number of limbic areas, namely the amygdala, the Ammon's horn of the hippocampus and the entorhinal cortex. In contrast, the density increased in three limbic areas: the dentate gyrus, the subiculum and the nucleus accumbens. Taken together, these data suggest that latent inhibition corresponds to alterations of sensory processing which renders difficult to state about the alteration of the transfers of the sensory information to structures involved in the control of emotional responses. As some brain areas show a specific increase of activity in cases of latent inhibition, further studies will investigate how the latter brain areas contribute to the other cell density alterations reported in this study and to the latent inhibition phenomenon itself.
潜伏抑制是指条件刺激与非条件刺激之间条件性联系的形成会因先前对条件刺激的暴露而延迟。潜伏抑制通常在条件性情绪反应的背景下进行研究，其中音调作为条件刺激，足部电击作为非条件刺激。本实验采用了这样的范式，即一些大鼠预先暴露于音调。在随后再次暴露于音调两小时后，使用c-fos免疫细胞化学来绘制激活的脑区。在涉及听觉、恐惧、应激和记忆的脑区测量免疫反应性神经元的密度。对于基础条件反射组，预先暴露于音调会降低听觉系统、涉及恐惧和应激的脑区以及一些边缘脑区（即杏仁核、海马体的海马角和内嗅皮质）中标记细胞的密度。相比之下，三个边缘脑区（齿状回、下托和伏隔核）的密度增加。综合来看，这些数据表明潜伏抑制对应于感觉处理的改变，这使得难以说明感觉信息向参与情绪反应控制的结构的传递变化情况。由于在潜伏抑制情况下一些脑区显示出特定的活动增加，进一步的研究将调查后述脑区如何对本研究中报道的其他细胞密度变化以及潜伏抑制现象本身产生影响。
