Posttraining lesion of the superior colliculus interferes with feature-negative discrimination of fear-potentiated startle.
Posttraining lesion of the superior colliculus interferes with feature-negative discrimination of fear-potentiated startle.
复制标题
训练后上丘损伤会干扰恐惧增强惊吓的特征阴性辨别。
DOI：
10.1016/s0166-4328(02)00405-9
复制
发表时间：
2003
影响因子：
2.7
通讯作者：
Falls,WilliamA
中科院分区：
文献类型：
--
作者：
Waddell,Jaylyn;Heldt,Scott;Falls,WilliamA
尽管人们对引发恐惧的神经回路知之甚少，但对减少恐惧的神经回路却知之甚少。本实验研究了上丘(SC)和背侧扣带周围灰质(DPAG)在减少通过特征-否定辨别过程训练的听觉特征所产生的条件性恐惧中的作用。在这个程序中，光加脚电击训练试验是穿插在试验中，光在光之前有噪音，而这种噪音和光的化合物不在脚电击之后。在这种特征阴性辨别训练结束时，大鼠给予兴奋毒性损毁SC或DPAG。使用恐惧强化的惊吓效应来评估恐惧的特征-负向辨别，其中条件性恐惧在操作上被定义为在有光的情况下相对于没有光的情况下增强的惊吓幅度。当噪音特征伴随着光时，对光的恐惧增强的惊吓减少了，这证明了对恐惧的消极辨别。SC的损害，而不是DPAG，干扰了特征--恐惧的负向辨别--强化惊吓，这表明SC在特征-负向恐惧辨别中起作用。在无光条件下，SC和DPAG损毁都促进了惊厥幅度，提示这些结构可能对声惊厥反射起紧张性抑制作用。SC接收多模式感觉信息，并投射参与产生条件性恐惧的前脑区域。因此，SC可以是特征-负识别电路的重要组件。
Though much is known about the neural circuits involved in the elicitation of fear, little is known about the neural circuits responsible for the reduction of fear. The present experiments investigated the contribution of the superior colliculus (SC) and the dorsal periacquaductal gray (dPAG) in the reduction of conditioned fear produced by an auditory feature trained in a feature-negative discrimination procedure. In this procedure, light plus foot shock training trials are interspersed with trials in which the light is preceded by a noise and this noise and light compound is not followed by foot shock. At the end of this feature-negative discrimination training, rats were given excitotoxic lesions of the SC or dPAG. Feature-negative discrimination of fear was assessed with the fear-potentiated startle effect in which conditioned fear is operationally defined as potentiated startle amplitude in the presence versus the absence of the light. Feature-negative discrimination of fear is evidenced by a reduction in fear-potentiated startle to the light when the noise feature accompanies the light. Lesions of the SC, but not the dPAG, interfered with feature-negative discrimination of fear-potentiated startle suggesting that the SC plays a role in feature-negative discrimination of fear. Both SC and dPAG lesions facilitated startle amplitude in the absence of the light suggesting that these structures may exert a tonic inhibition on the acoustic startle reflex. The SC receives polymodal sensory information and is known to project forebrain areas involved in the production of conditioned fear. Thus, the SC may be an important component of the feature-negative discrimination circuit.