Weisenbach Sara L, Kassel Michelle T, Rao Julia, Weldon Annie L, Avery Erich T, Briceno Emily M, Ajilore Olusola, Mann Megan, Kales Helen C, Welsh Robert C, Zubieta Jon-Kar, Langenecker Scott A
Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA; Research and Development, Jesse Brown VA Medical Center, Chicago, IL, USA.
Int J Geriatr Psychiatry. 2014 Nov;29(11):1104-15. doi: 10.1002/gps.4165. Epub 2014 Jun 20.
Verbal memory difficulties are common among individuals with late-life depression (LLD), though there is limited knowledge about disruptions to underlying cerebral circuitry. The purpose of this study is to examine aberrations to cerebral networks implicated in encoding novel verbal semantic material among older adults with LLD.
Twenty-four older adults with early-onset LLD and 23 non-depressed comparisons participated in the study. Participants completed a word list-learning task while undergoing functional magnetic resonance imaging.
In the context of equivalent recall and recognition of words following scanning and similar hippocampal volumes, patients with LLD exhibited less activation in structures known to be relevant for new learning and memory, including hippocampus, parahippocampal gyrus, insula, and cingulate, relative to non-ill comparisons. An important region in which the LLD group displayed greater activation than the non-depressed comparison group was in left inferior frontal gyrus, an area involved in cognitive control and controlled semantic/phonological retrieval and analysis; this region may be critical for LLD patients to consolidate encoded words into memory.
Functional irregularities found in LLD patients may reflect different modes of processing to-be-remembered information and/or early changes predictive of incipient cognitive decline. Future studies might consider mechanisms that could contribute to these functional differences, including hypothalamic-pituitary-adrenal axis functioning and vascular integrity, and utilize longitudinal designs in order to understand whether functional changes are predictive of incipient cognitive decline.
言语记忆困难在老年抑郁症（LLD）患者中很常见，尽管对潜在脑回路中断的了解有限。本研究的目的是检查LLD老年患者中与编码新言语语义材料相关的脑网络异常。
24名早发性LLD老年患者和23名非抑郁症对照者参与了研究。参与者在进行功能磁共振成像时完成了单词列表学习任务。
在扫描后单词的等效回忆和识别以及海马体积相似的情况下，与非患病对照者相比，LLD患者在已知与新学习和记忆相关的结构中表现出较少的激活，包括海马体、海马旁回、脑岛和扣带回。LLD组比非抑郁症对照组表现出更大激活的一个重要区域是左下额叶回，该区域参与认知控制以及受控的语义/语音检索和分析；该区域可能对LLD患者将编码的单词巩固到记忆中至关重要。
在LLD患者中发现的功能异常可能反映了处理待记忆信息的不同模式和/或预测早期认知衰退的早期变化。未来的研究可能会考虑有助于这些功能差异的机制，包括下丘脑 - 垂体 - 肾上腺轴功能和血管完整性，并采用纵向设计以了解功能变化是否可预测早期认知衰退。
