Wang Jianli, Eslinger Paul J, Smith Michael B, Yang Qing X
Center for Nuclear Magnetic Resonance Research, Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
J Gerontol A Biol Sci Med Sci. 2005 Apr;60(4):510-4. doi: 10.1093/gerona/60.4.510.
The function of human olfaction declines with advancing age. An important question centers on whether functional alterations to olfactory brain structures accompany age-related behavioral changes. In the present study, we tested the hypothesis that aged adults have intact though reduced activity in the central olfactory system using functional magnetic resonance imaging (fMRI).
University of Pennsylvania Smell Identification Test (UPSIT) was used to test the smell function of 11 young (23.9 +/- 1.6 years) and 8 aged (66.4 +/- 4.4 years) healthy participants. Then, the participants received fMRI at 3.0 T with lavender and spearmint as stimulants. After fMRI, the participants provided ratings for the odorants' intensity and pleasantness.
The average UPSIT score of the aged adults was 34.1 +/- 1.5, which was significantly lower than that of the young adults (37.3 +/- 1.1) (p =.0004). Both age groups showed significant activation in major olfactory brain structures, including the primary olfactory cortex, entorhinal cortex, hippocampus and parahippocampal cortex, thalamus, hypothalamus, orbitofrontal cortex, and insular cortex and its extension into the inferior lateral frontal region. The aged adults showed less brain activity in olfactory structures (p =.022), consistent with lower ratings of odor intensity and UPSIT scores. Activation intensity in bilateral primary olfactory cortex areas and right insular cortex was also comparatively weaker (p <.019).
Results demonstrate that significant activation in aged adults can be observed in all the olfactory brain structures that are activated in young adults, but with lower activation volume and intensity. This finding provides a necessary baseline for further investigations in olfaction and aging.
人类嗅觉功能随年龄增长而衰退。一个重要问题聚焦于嗅觉脑结构的功能改变是否伴随与年龄相关的行为变化。在本研究中，我们使用功能磁共振成像（fMRI）来检验老年成年人中枢嗅觉系统活动虽有所降低但仍保持完整这一假设。
使用宾夕法尼亚大学嗅觉识别测试（UPSIT）对11名年轻（23.9±1.6岁）和8名老年（66.4±4.4岁）健康参与者的嗅觉功能进行测试。然后，参与者在3.0T的条件下接受fMRI检查，以薰衣草和留兰香作为刺激物。fMRI检查后，参与者对气味剂的强度和愉悦度进行评分。
老年成年人的UPSIT平均得分为34.1±1.5，显著低于年轻成年人（37.3±1.1）（p=0.0004）。两个年龄组在主要嗅觉脑结构中均表现出显著激活，包括初级嗅觉皮层、内嗅皮层、海马体和海马旁皮层、丘脑、下丘脑、眶额皮层、岛叶皮层及其延伸至下外侧额叶区域。老年成年人在嗅觉结构中的脑活动较少（p=0.022），这与较低的气味强度评分和UPSIT得分一致。双侧初级嗅觉皮层区域和右侧岛叶皮层的激活强度也相对较弱（p<0.019）。
结果表明，在年轻成年人中被激活的所有嗅觉脑结构在老年成年人中均可观察到显著激活，但激活量和强度较低。这一发现为嗅觉与衰老的进一步研究提供了必要的基线。
