NORMAL AGING OF BRAIN STRUCTURE AND FUNCTION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 目的：用DTI确定白质微结构随年龄的差异，并将局部FA与注意力、工作记忆和加速过程的选择性成分的功能联系起来。 方法：我们测试了71名女性和59名男性，包括单次激发自旋回波平面冠状DTI序列以及快速自旋回波(FSE)和破坏的梯度回声(SPGR)结构序列。其中一些受试者(22名中年人，平均年龄41岁，18名老年人，平均年龄69岁)进行了一项全局/局部视觉操作测试，该测试涉及对取决于右半球功能的全局特征的加工，以及取决于左半球功能的局部细节的加工。 结果：我们发现在局部-全局特征加工中，年龄对注意机制的选择性效应超过了一般的减速效应，包括在老年人选择性注意条件下增强的局部优先效应。我们还发现，老年期的膝部与一致性效应和局部抑制效应显著相关，这表明冲突的局部-全局信息是以推-拉方式在半球间加工的，老年受试者的膝部尺寸变小会引起局部干扰大于全局干扰的不平衡抑制模式。 结论：衰老的视觉空间缺陷可能更多地取决于这一信息在两个大脑半球之间的处理和交换方式，而不是大脑半球功能障碍本身。 在另一项对双回波、自旋回波、3毫米厚的连续冠状磁共振图像上测量的海马体体积的单独分析中，男性和女性都没有显示出海马体体积与年龄之间的显著相关性。相比之下，男性和女性的颞叶皮质灰质体积都随着年龄的增长而显著下降。当只考虑50岁或50岁以上的受试者时，海马体体积与年龄之间缺乏相关性。测量灵敏度足以检测到海马体大小的微小但显著的偏侧性差异，右侧海马体前缘大于左侧。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Aims: Identify age-dependent differences in white matter microstructure with DTI and relate regional FA to function of selective components of attention, working memory, and speeded processes. Methods: We have tested 71 women and 59 men spanning the adult age range in a protocol that includes a single shot spin-echo echo-planar coronal DTI sequence as well as fast spin echo (FSE) and SPoiled Gradient Recalled Echo (SPGR) structural sequences. Some of these subjects (22 middle age, mean age 41 years and 18 elderly, mean age 69 years) performed a Global/Local visuoperceptual test that involves processing of global features, dependent on right hemispheric functioning, and local details, dependent on left hemispheric functioning. Results: We found selective effects of age on attentional mechanisms in local-global feature processing that were beyond general slowing effects including an enhanced local precedence effect in selective but not divided attention conditions in older subjects. We also found significant correlations between the genu of the corpus callosum and the congruency effect and the local inhibition effect suggesting that conflicting local-global information is processed interhemispherically in a push-pull fashion and that reduced genu size of the corpus callosum in older subjects invokes an unbalanced inhibition pattern with greater local than global interference. Conclusions: Visuospatial deficits in aging may depend more on how this information is processed and exchanged between the two hemispheres than on hemispheric dysfunction per se. In a separate analysis of hippocampal volumes measured on dual-echo, spin-echo, 3 mm thick, contiguous coronal magnetic resonance images neither the men nor the women showed significant correlations between hippocampal volumes and age. By contrast, temporal lobe cortical gray matter volumes declined significantly with age both in men and in women. The lack of relationship between hippocampal volume and age endured when only subjects 50 years or older were considered. Measurement sensitivity was adequate to detect the small but significant laterality difference in hippocampal size, with the anterior reaches of the right hippocampus larger than the left.