INSERM U1077, 14000 Caen, France; Université de Caen Basse-Normandie, UMR-S1077, 14000 Caen, France; Ecole Pratique des Hautes Etudes, UMR-S1077, 14000 Caen, France; CHU de Caen, U1077, 14000 Caen, France.
INSERM U1077, 14000 Caen, France; Université de Caen Basse-Normandie, UMR-S1077, 14000 Caen, France; Ecole Pratique des Hautes Etudes, UMR-S1077, 14000 Caen, France; CHU de Caen, U1077, 14000 Caen, France.
Neuron. 2014 Mar 19;81(6):1417-1428. doi: 10.1016/j.neuron.2014.01.026.
Alzheimer's disease (AD) and semantic dementia (SD) are both characterized by severe atrophy in the hippocampus, a brain region underlying episodic memory; paradoxically, episodic memory is relatively preserved in SD. Here, we used intrinsic connectivity analyses and showed that the brain networks differentially vulnerable to each disease converge to the hippocampus in the healthy brain. As neurodegeneration is thought to spread within preexisting networks, the common hippocampal atrophy in both diseases is likely due to its location at the crossroad between both vulnerable networks. Yet, we showed that in the normal brain, these networks harbor different functions, with episodic memory relying on the AD-vulnerable network only. Overall, disease-associated cognitive deficits seem to reflect the disruption of targeted networks more than atrophy in specific brain regions: in AD, over hippocampal atrophy, episodic memory deficits are likely due to disconnection within a memory-related network.
阿尔茨海默病（AD）和语义性痴呆（SD）的特征均为海马体严重萎缩，而海马体是形成情景记忆的脑区；但奇怪的是，SD 患者的情景记忆相对保留。在此，我们采用内在连通性分析并表明，两种疾病中易受影响的大脑网络在健康大脑中汇聚到海马体。由于神经退行性变被认为在预先存在的网络中传播，因此两种疾病中海马体的共同萎缩可能是由于其位于两个易受影响的网络的交汇处。然而，我们发现，在正常大脑中，这些网络具有不同的功能，情景记忆仅依赖于 AD 易损网络。总的来说，与疾病相关的认知缺陷似乎反映了特定脑区萎缩以外的靶向网络的破坏：在 AD 中，除了海马体萎缩之外，情景记忆缺陷可能是由于与记忆相关的网络内的连接中断所致。
