Rémy Florence, Mirrashed Fakhereh, Campbell Barry, Richter Wolfgang
MR Technology, Institute for Biodiagnostics, National Research Council, Winnipeg, Canada.
Neuroimage. 2005 Mar;25(1):253-66. doi: 10.1016/j.neuroimage.2004.10.045. Epub 2004 Dec 10.
Anatomical and functional MRI images were acquired in a group of healthy elderly subjects (n = 11) and a group of patients diagnosed with probable Alzheimer's disease, from mild to moderate severity (n = 8). During functional sessions, verbal episodic Encoding and Recognition tasks were presented to subjects. Both groups were compared in terms of gray matter volume and cerebral activation. Furthermore, in the AD group, correlations between hippocampal gray matter volume and whole-brain activations were examined. When compared to healthy controls, AD patients presented significant gray matter atrophy as well as reduced activations during Encoding and Recognition in the medial temporal lobes and inferior parietal/superior temporal associative areas. In the same regions, the fMRI activity elicited by the Recognition task was positively correlated with hippocampal gray matter volume. Moreover, an increase of left prefrontal activity during Encoding and Recognition was observed in AD patients relative to controls and was correlated with memory performance. This additional activity elicited by episodic memory processes was not found to correlate with the degree of medial temporal atrophy in our group of patients. Our study shows that function in brain regions critical to episodic memory is altered in AD. During episodic Recognition, these functional changes may closely correlate with the progressive structural changes observed in the hippocampal region.
对一组健康老年受试者（n = 11）和一组被诊断为可能患有阿尔茨海默病、病情从轻度到中度的患者（n = 8）进行了解剖学和功能性磁共振成像（MRI）扫描。在功能扫描期间，向受试者呈现言语情景编码和识别任务。对两组的灰质体积和大脑激活情况进行了比较。此外，在阿尔茨海默病组中，研究了海马体灰质体积与全脑激活之间的相关性。与健康对照组相比，阿尔茨海默病患者在内侧颞叶以及顶叶下部/颞叶上部联合区域的编码和识别过程中，出现了显著的灰质萎缩以及激活减少的情况。在相同区域，识别任务引发的功能磁共振成像（fMRI）活动与海马体灰质体积呈正相关。此外，与对照组相比，阿尔茨海默病患者在编码和识别过程中左侧前额叶活动增加，且与记忆表现相关。在我们的患者组中，情景记忆过程引发的这种额外活动与内侧颞叶萎缩程度并无关联。我们的研究表明，阿尔茨海默病患者中对情景记忆至关重要的脑区功能发生了改变。在情景识别过程中，这些功能变化可能与海马体区域观察到的渐进性结构变化密切相关。
