Murty Vishnu P, Sambataro Fabio, Das Saumitra, Tan Hao-Yang, Callicott Joseph H, Goldberg Terry E, Meyer-Lindenberg Andreas, Weinberger Daniel R, Mattay Venkata S
National Institutes of Health, Bethesda, MD, USA.
J Cogn Neurosci. 2009 Oct;21(10):1920-33. doi: 10.1162/jocn.2009.21130.
Healthy aging has been shown to modulate the neural circuitry underlying simple declarative memory; however, the functional impact of negative stimulus valence on these changes has not been fully investigated. Using BOLD fMRI, we explored the effects of aging on behavioral performance, neural activity, and functional coupling during the encoding and retrieval of novel aversive and neutral scenes. Behaviorally, there was a main effect of valence with better recognition performance for aversive greater than neutral stimuli in both age groups. There was also a main effect of age with better recognition performance in younger participants compared to older participants. At the imaging level, there was a main effect of valence with increased activity in the medial-temporal lobe (amygdala and hippocampus) during both encoding and retrieval of aversive relative to neutral stimuli. There was also a main effect of age with older participants showing decreased engagement of medial-temporal lobe structures and increased engagement of prefrontal structures during both encoding and retrieval sessions. Interestingly, older participants presented with relatively decreased amygdalar-hippocampal coupling and increased amygdalar-prefrontal coupling when compared to younger participants. Furthermore, older participants showed increased activation in prefrontal cortices and decreased activation in the amygdala when contrasting the retrieval of aversive and neutral scenes. These results suggest that although normal aging is associated with a decline in declarative memory with alterations in the neural activity and connectivity of brain regions underlying simple declarative memory, memory for aversive stimuli is relatively better preserved than for neutral stimuli, possibly through greater compensatory prefrontal cortical activity.
健康衰老已被证明可调节简单陈述性记忆背后的神经回路；然而，负面刺激效价对这些变化的功能影响尚未得到充分研究。我们使用血氧水平依赖性功能磁共振成像（BOLD fMRI），探究了衰老对新的厌恶场景和中性场景编码与检索过程中的行为表现、神经活动及功能耦合的影响。行为学上，效价存在主效应，两个年龄组中对厌恶刺激的识别表现均优于中性刺激。年龄也存在主效应，年轻参与者的识别表现优于年长参与者。在成像层面，效价存在主效应，与中性刺激相比，在厌恶刺激的编码和检索过程中，内侧颞叶（杏仁核和海马体）的活动增加。年龄也存在主效应，年长参与者在编码和检索过程中，内侧颞叶结构的参与度降低，前额叶结构的参与度增加。有趣的是，与年轻参与者相比，年长参与者的杏仁核 - 海马体耦合相对减少，杏仁核 - 前额叶耦合增加。此外，在对比厌恶场景和中性场景的检索时，年长参与者前额叶皮质的激活增加，杏仁核的激活减少。这些结果表明，尽管正常衰老与陈述性记忆衰退以及简单陈述性记忆背后脑区的神经活动和连接改变有关，但厌恶刺激的记忆可能比中性刺激的记忆保存得相对更好，这可能是通过更大程度的前额叶皮质代偿性活动实现的。
