The effect of age and fixation instability on retinotopic mapping of primary visual cortex
The effect of age and fixation instability on retinotopic mapping of primary visual cortex
复制标题
DOI：
10.1167/iovs.07-1621
复制
发表时间：
2008-08-01
影响因子：
4.4
通讯作者：
Rubin, Gary S.
中科院分区：
文献类型：
--
作者：
Crossland, Michael D.;Morland, Antony B.;Rubin, Gary S.
目的。功能性磁共振成像（fMRI）实验通常在年轻人身上进行，以确定视皮层的视网膜结构，这些年轻人被认为能够在整个试验期间保持稳定的注视。作者量化了年龄和注视稳定性对初级视觉皮层视网膜专题图质量的影响。方法。通过使用 3T fMRI 扫描仪，作者测量了 6 名视力正常的老年人和 6 名年轻人的皮层活动，观察了直径为 30 的不断扩大的闪烁棋盘刺激。记录了显示对视觉刺激的任何血氧水平依赖性（BOLD）活动的扁平初级视觉皮层（V1）的区域以及对刺激的中央3.75（与我们的目标的中央环相关）做出响应的区域。当参与者使用红外凝视追踪器在扫描仪外观察相同的刺激时，测量了注视稳定性。结果。 V1 面积没有与年龄相关的变化。然而，老年观察者对视觉刺激的 V1 活跃比例低于年轻观察者（总体活性：老年观察者 V1 区域的 89.8%，年轻观察者为 98.6%；P < 0.05）。对于目标的中心 3.75，这种效果更为明显（老年受试者，26.4%；年轻受试者，40.7%；P < 0.02）。注视稳定性与年龄或初级视觉皮层活动强度之间不存在显着关系。结论。尽管皮质区域保持不变，但健康老年人在 V1 中的 BOLD 活动比年轻人要少。注视稳定性的正常变化不会对确定视觉皮层视网膜结构的实验的准确性产生显着影响。
PURPOSE. Functional magnetic resonance imaging (fMRI) experiments determining the retinotopic structure of visual cortex have commonly been performed on young adults, who are assumed to be able to maintain steady fixation throughout the trial duration. The authors quantified the effects of age and fixation stability on the quality of retinotopic maps of primary visual cortex.METHODS. With the use of a 3T fMRI scanner, the authors measured cortical activity in six older and six younger normally sighted participants observing an expanding flickering checkerboard stimulus of 30 diameter. The area of flattened primary visual cortex (V1) showing any blood oxygen level-dependent (BOLD) activity to the visual stimulus and the area responding to the central 3.75 of the stimulus (relating to the central ring of our target) were recorded. Fixation stability was measured while participants observed the same stimuli outside the scanner using an infrared gazetracker.RESULTS. There were no age-related changes in the area of V1. However, the proportion of V1 active to our visual stimulus was lower for the older observers than for the younger observers (overall activity: 89.8% of V1 area for older observers, 98.6% for younger observers; P < 0.05). This effect was more pronounced for the central 3.75 of the target (older subjects, 26.4%; younger subjects, 40.7%; P < 0.02). No significant relationship existed between fixation stability and age or the magnitude of activity in the primary visual cortex.CONCLUSIONS. Although the cortical area remains unchanged, healthy older persons show less BOLD activity in V1 than do younger persons. Normal variations in fixation stability do not have a significant effect on the accuracy of experiments to determine the retinotopic structure of the visual cortex.