Neuroanatomical correlates of episodic encoding and retrieval in young and elderly subjects
Neuroanatomical correlates of episodic encoding and retrieval in young and elderly subjects
复制标题
DOI：
10.1093/brain/awg005
复制
发表时间：
2003-01-01
期刊：
影响因子：
14.5
通讯作者：
Jonker, C
中科院分区：
文献类型：
--
作者：
Daselaar, SM;Veltman, DJ;Jonker, C
病变研究令人信服地表明，内侧颞叶(MTL)和额叶对情景记忆至关重要。人们普遍发现，衰老对情景记忆表现通常有负面影响，这可能与额叶和内侧颞叶脑区的神经功能变化有关。在本研究中，我们使用功能磁共振成像(FMRI)来分别研究编码和提取在年龄相关性记忆衰退中的作用。为此，我们比较了三组在偶然编码(对名词的愉快/不愉快的判断)和随后的提取(识别)过程中获得的大脑活动模式：一组年轻受试者，一组表现出记忆能力下降的老年受试者(ELD-RED)，以及一组表现仍在正常范围内的老年受试者(ELD-NORM)。这使我们能够区分与年龄相关的影响记忆功能的大脑活动变化和那些对记忆功能没有明显影响的变化，因为它们在两个老年组中都存在。与以前关于这一主题的成像研究相反，我们使用(自定进度的)事件相关功能磁共振成像来控制不同组之间的表现水平差异，只包括正确的回答。将成功记忆项目的编码与基线(按左/按右)进行比较，与ELD-RED受试者相比，年轻受试者左侧前MTL区的脑激活显著增加，但与ELD-NORMAL受试者相比，差异无统计学意义。将被正确拒绝的项目(提取尝试)与基线进行比较，ELD-RED组显示出与其他组相比，整个大脑的整体活动明显增加。然而，当正确识别的项目(检索尝试+成功)与正确拒绝的项目(检索尝试)直接比较时，这些差异大大减小，显示出左侧顶叶、脾后和左侧前额前区域的共同活动。因此，我们得出结论，ELD-RED组的表现下降很可能是由于编码过程中MTL功能障碍所致。在检索尝试期间观察到的差异可能反映了策略上的差异。在检索成功方面没有观察到差异，这表明年龄增长不会影响支持信息实际恢复的过程。
Lesion studies have shown convincingly that the medial temporal lobes (MTL) and frontal lobes are critical to episodic memory. Ageing generally has been found to have a generally negative effect on episodic memory performance, which might relate to neurofunctional changes in the frontal and medial temporal brain regions. In the present study, we used functional MRI (fMRI) to investigate separately the contributions of encoding and retrieval to the age-related decline in memory. To this end, we compared brain activity patterns obtained during incidental encoding (pleasant/unpleasant judgements about nouns) and subsequent retrieval (recognition) in three groups: a group of young subjects, a group of elderly subjects showing reduced memory performance (ELD-RED), and a group of elderly subjects who still performed in the normal range (ELD-NORM). This allowed us to differentiate between age-related changes in brain activity that affect memory function and those that do not have an apparent effect on memory function, because they are found in both elderly groups. Contrary to previous imaging studies on this topic, we used (self-paced) event-related fMRI to control for differences in performance level across groups by including correct responses only. Comparing the encoding of successfully remembered items with baseline (press left/press right), the young subjects showed a significant increase in brain activation in the left anterior MTL compared with the ELD-RED but not the ELD-NORM subjects. Comparing correctly rejected items (retrieval attempt) with baseline, the ELD-RED group showed much increased overall activity throughout the brain compared with the other groups. However, when correctly recognized items (retrieval attempt + success) were com pared directly with correctly rejected items (retrieval attempt), these differences were greatly reduced, revealing common activity in the left parietal, retrosplenial and left anterior prefrontal regions. Therefore, we conclude that the reduced performance in the ELD-RED group is likely to be due to MTL dysfunction during encoding. The differences observed during retrieval attempts may reflect strategic differences. The lack of differences observed in relation to retrieval success suggests that ageing does not affect the processes that support the actual recovery of information.