Neuroimaging Laboratory, Santa Lucia Foundation, IRCCS, Rome, Italy.
Department of Clinical and Behavioural Neurology, Santa Lucia Foundation, IRCCS, Rome, Italy.
J Neuropsychol. 2020 Mar;14(1):46-68. doi: 10.1111/jnp.12174. Epub 2018 Nov 19.
The role of the hippocampus and neocortical areas in the retrieval of past memories in pre-dementia Alzheimer's disease (AD) patients was investigated. The aim was to assess whether the hippocampus has a temporary role in memory trace formation, according to the Cortical Reallocation Theory (CRT), or whether it continuously updates and enriches memories, according to the Multiple Trace Theory. According to the former theory, hippocampal damage should affect more recent memories, whereas the association cortex is expected to affect memories of the entire lifespan. In the second case, damage to either the hippocampus or the association cortices should affect memories of the entire lifespan. Seventeen patients with amnestic Mild Cognitive Impairment due to AD were submitted to autobiographical (i.e., episodic and semantic personal) memory assessment. Patients underwent MRI for the acquisition of T1-weighted brain volumes. Voxel-based morphometry was used to assess correlations between grey matter (GM) volumes and autobiographical memory. Correlation analyses revealed a strict association between GM volumes in the hippocampus and patients' ability to retrieve the most recent but not the oldest autobiographical memories in both aspects, episodic and semantic. Moreover, patients' GM volumes in the pre-frontal and temporal polar areas were associated with recollection of episodic and semantic events, respectively. Finally, GM volumes in the precuneus and occipital cortex were associated with retrieval of the most recent episodic events. These findings indicate that the hippocampus has a specific time-dependent role; thus, they support the CRT.
本研究旨在调查海马体和新皮质区域在痴呆前期阿尔茨海默病（AD）患者提取过去记忆中的作用。目的是评估海马体是否根据皮质再分配理论（Cortical Reallocation Theory，CRT）在记忆痕迹形成中起暂时作用，还是根据多重痕迹理论（Multiple Trace Theory）不断更新和丰富记忆。根据前者的理论，海马体损伤应影响最近的记忆，而联合皮质预计会影响整个生命周期的记忆。在后一种情况下，无论是海马体还是联合皮质的损伤都应该影响整个生命周期的记忆。17 名因 AD 导致的遗忘型轻度认知障碍患者接受了自传体（即情景和语义个人）记忆评估。患者接受 MRI 以获取 T1 加权脑容积。体素形态计量学用于评估灰质（GM）体积与自传体记忆之间的相关性。相关分析显示，GM 体积在海马体与患者检索最近但不是最古老的情景和语义自传体记忆的能力之间存在严格关联。此外，患者的额极和颞极前皮质区 GM 体积与情景事件的回忆分别相关。最后，顶内沟和枕叶皮质的 GM 体积与最近的情景事件的检索相关。这些发现表明，海马体具有特定的时间依赖性作用；因此，它们支持 CRT。
