Conrad Cheryl D
Arizona State University, Department of Psychology.
Nonlinearity Biol Toxicol Med. 2005;3(1):57-78. doi: 10.1080/15401420490900245.
This review evaluates the effects of glucocorticoids (GCs), the adrenal steroids released in response to stress, on memory functions requiring the hippocampus in animals and humans. The data support the hypothesis that the learning function between GCs and hippocampal-dependent memory is modulated by 1) the aversive nature of the learning paradigm and 2) stage of memory processing (acquisition, consolidation, retrieval). When tasks are minimally aversive, the glucocorticoid receptor (GR) mediates an inverted U-shaped relationship between GC levels and hippocampal function, while the mineralocorticoid receptor (MR) mediates attentional processes and/or reaction to novelty. This inverted U-shaped relationship during minimally aversive training paradigms describes GC-mediated memory processing at both acquisition and consolidation. In contrast, highly aversive paradigms activate the amygdala and elevate GCs as part of the training procedure, revealing a nonlinear inverted U-shaped relationship during acquisition and a positive linear function during consolidation. Thus, highly aversive tasks that activate the amygdala shift the memory function from an inverted U-shaped curve to a linear representation between GC levels and memory consolidation.
本综述评估了糖皮质激素（GCs），即机体在应激状态下释放的肾上腺类固醇，对动物和人类中需要海马体参与的记忆功能的影响。数据支持以下假设：糖皮质激素与海马体依赖性记忆之间的学习功能受到1）学习范式的厌恶性质和2）记忆处理阶段（获取、巩固、检索）的调节。当任务的厌恶程度最低时，糖皮质激素受体（GR）介导糖皮质激素水平与海马体功能之间呈倒U形关系，而盐皮质激素受体（MR）介导注意力过程和/或对新奇事物的反应。在最低厌恶程度的训练范式中，这种倒U形关系描述了获取和巩固过程中糖皮质激素介导的记忆处理。相比之下，高度厌恶的范式会激活杏仁核并在训练过程中提高糖皮质激素水平，在获取过程中呈现非线性倒U形关系，在巩固过程中呈现正线性函数关系。因此，激活杏仁核的高度厌恶任务会将记忆功能从倒U形曲线转变为糖皮质激素水平与记忆巩固之间的线性关系。
