Impaired structure and function of the hippocampus is a valuable predictor of progression from amnestic mild cognitive impairment（a MCI） to Alzheimer＇s disease（AD）. As a part of the medial temporal lobe memory system,the hippocampus is one of the brain regions affected earliest by AD neuropathology,and shows progressive degeneration as a MCI progresses to AD. Currently,no validated biomarkers can precisely predict the conversion from a MCI to AD. Therefore,there is a great need of sensitive tools for the early detection of AD progression. In this review,we summarize the specifi c structural and functional changes in the hippocampus from recent a MCI studies using neurophysiological and neuroimaging data. We suggest that a combination of advanced multi-modal neuroimaging measures in discovering biomarkers will provide more precise and sensitive measures of hippocampal changes than using only one of them. These will potentially affect early diagnosis and disease-modifying treatments. We propose a new sequential and progressive framework in which the impairment spreads from the integrity of fibers to volume and then to function in hippocampal subregions. Meanwhile,this is likely to be accompanied by progressive impairment of behavioral and neuropsychological performance in the progression of a MCI to AD.
目的比较以氯氮平和氯丙嗪维持治疗的精神分裂症患者的认知功能与述情障碍。方法分别纳入以氯氮平、氯丙嗪维持治疗且病情稳定的男性精神分裂症患者各24例,以及男性正常对照24名。采用数字划消测验、言语流畅性测验、连线测验A和B、动物命名测验、Stroop色—词测验、韦氏智力测验中国版木块图、空间广度测验等神经心理测验评估三组被试的认知功能,并采用多伦多述情障碍量表(the twenty-item Toronto alexithymia scale,TAS-20)评估被试述情障碍。结果两患者组所有神经心理测验得分均低于对照组(P=0.02),两患者组TAS-20各因子分及总分均高于对照组(P<0.01),两患者组之间认知功能及述情障碍评分差异均无统计学意义(P>0.05)。多因素线性回归分析显示,氯氮平组注意功能与TAS总分(β=-0.20,P=0.02)相关联,执行功能与TAS情感辨别能力因子(β=-0.26,P=0.03)相关联,空间功能与TAS情感描述能力因子(β=-0.24,P<0.01)相关联;氯丙嗪组注意功能与TAS情感描述能力因子(β=-1.24,P<0.01)相关联,执行功能与TAS情感描述能力因子(β=-0.33,P=0.02)相关联。结论精神分裂症患者在药物维持治疗期仍存在广泛的认知功能损害及述情障碍,且认知损害与述情障碍间具有一定关联。
老年抑郁症（late life depression,LLD）是指老年期（≥60岁）这一特定人群的抑郁症,常伴随认知功能损害[1],近年来老年抑郁症认知功能损害逐渐得到人们关注,本文简要综述老年抑郁症认知功能损害主要领域,并阐述各认知功能领域间相互关系以及抗抑郁药治疗与认知功能相互影响,为伴有认知功能损害的老年抑郁症患者临床治疗提供有价值的信息.
The regional specifi city of hippocampal abnormalities in late-life depression（LLD） has been demonstrated in previous studies. In this study,we sought to examine the functional connectivity（FC） patterns of hippocampal subregions in remitted late-onset depression（r LOD）,a special subtype of LLD. Fourteen r LOD patients and 18 healthy controls underwent clinical and cognitive evaluations as well as resting-state functional magnetic resonance imaging scans at baseline and at ~21 months of follow-up. Each hippocampus was divided into three parts,the cornu ammonis（CA）,the dentate gyrus,and the subicular complex,and then six seed-based hippocampal subregional networks were established.Longitudinal changes of the six networks over time were directly compared between the rL OD and control groups. From baseline to follow-up,the r LOD group showed a greater decline in connectivity of the left CA to the bilateral posterior cingulate cortex/precuneus（PCC/PCUN）,but showed increased connectivity of the right hippocampal subregional networks with the frontal cortex（bilateral medial prefrontal cortex/anterior cingulate cortex and supplementary motor area）. Further correlative analyses revealed thatthe longitudinal changes in FC between the left CA and PCC/PCUN were positively correlated with longitudinal changes in the Symbol Digit Modalities Test（r = 0.624,P = 0.017） and the Digit Span Test（r = 0.545,P = 0.044） scores in the r LOD group. These results may provide insights into the neurobiological mechanism underlying the cognitive dysfunction in r LOD patients.
