Department of Psychology, University of Washington, Seattle, Washington, USA.
eScience Institute, University of Washington, Seattle, Washington, USA.
Hum Brain Mapp. 2023 Jun 1;44(8):3123-3135. doi: 10.1002/hbm.26267. Epub 2023 Mar 10.
The neural pathways that carry information from the foveal, macular, and peripheral visual fields have distinct biological properties. The optic radiations (OR) carry foveal and peripheral information from the thalamus to the primary visual cortex (V1) through adjacent but separate pathways in the white matter. Here, we perform white matter tractometry using pyAFQ on a large sample of diffusion MRI (dMRI) data from subjects with healthy vision in the U.K. Biobank dataset (UKBB; N = 5382; age 45-81). We use pyAFQ to characterize white matter tissue properties in parts of the OR that transmit information about the foveal, macular, and peripheral visual fields, and to characterize the changes in these tissue properties with age. We find that (1) independent of age there is higher fractional anisotropy, lower mean diffusivity, and higher mean kurtosis in the foveal and macular OR than in peripheral OR, consistent with denser, more organized nerve fiber populations in foveal/parafoveal pathways, and (2) age is associated with increased diffusivity and decreased anisotropy and kurtosis, consistent with decreased density and tissue organization with aging. However, anisotropy in foveal OR decreases faster with age than in peripheral OR, while diffusivity increases faster in peripheral OR, suggesting foveal/peri-foveal OR and peripheral OR differ in how they age.
从中央凹、黄斑和周边视野传递信息的神经通路具有不同的生物学特性。视放射（OR）通过白质中相邻但分开的通路，将来自丘脑的中央凹和周边信息传递到初级视觉皮层（V1）。在这里，我们在 UKBB 数据集（UKBB；N=5382；年龄 45-81 岁）的健康视力受试者的大量扩散 MRI（dMRI）数据上使用 pyAFQ 进行白质束追踪。我们使用 pyAFQ 来描述 OR 中传输中央凹、黄斑和周边视野信息的部分的白质组织特性，并描述这些组织特性随年龄的变化。我们发现：（1）无论年龄如何，中央凹和黄斑 OR 的各向异性分数较高，平均扩散系数较低，平均峰度较高，这与中央凹/旁中央通路中神经纤维密度更高、更有组织有关，（2）年龄与扩散增加和各向异性降低以及峰度降低有关，这与衰老时密度和组织组织减少有关。然而，中央凹 OR 的各向异性随年龄的下降速度比周边 OR 快，而周边 OR 的扩散速度增加较快，这表明中央凹/旁中央 OR 和周边 OR 在衰老方式上存在差异。
