Arrigo Alessandro, Calamuneri Alessandro, Mormina Enricomaria, Gaeta Michele, Quartarone Angelo, Marino Silvia, Anastasi Giuseppe Pio, Aragona Pasquale
Department of Biomedical Sciences and Morphological and Functional Images University of Messina, Messina, Italy.
Department of Neurosciences, University of Messina, Messina, Italy.
Invest Ophthalmol Vis Sci. 2016 Jan 1;57(1):1-5. doi: 10.1167/iovs.15-18082.
To study optic radiations connectivity by means of advanced magnetic resonance imaging (MRI) approaches, noninvasively, in vivo, in healthy human brains.
Sixteen healthy subjects (nine males, age range, 25-40 years) were included in this study. Morphologic and diffusion data were acquired by means of a 3T MRI scanner. Using an advanced tractographic technique, based on probabilistic constrained spherical deconvolution algorithm, postprocessing analyses were performed. Statistical analysis was carried out using the 2-tailed Wilcoxon rank sum test. Outcome measure was the percentage distribution of optic radiations streamlines in different cortical visual areas (V1-V5). The latter were detected by means of Juelich probabilistic histologic atlas.
Average connectivity analyses revealed that the optic radiations are mainly distributed in V1 (47.46% ± 5.5) and V2 (32.45% ± 3.98); furthermore, direct connections with V3 (7.81 ± 3.06), V4 (4.22% ± 1.82), and V5 (8.06% ± 2.65) were also detected.
In the present study, the connectivity profile of optic radiations, obtained by means of algorithms not affected by the limitations of other tractographic techniques, such as diffusion tensor imaging, was shown in healthy human brains. Interestingly, direct connections with V4 were detected for the first time in humans; moreover, further support on the possible existence of V5 connections was provided. Our findings showed new connections between lateral geniculate nuclei and cortical visual areas, giving a further possible comprehension of the phenomena leading to the visual signals elaboration.
采用先进的磁共振成像（MRI）方法，在健康人脑体内进行无创性研究，以探讨视辐射的连通性。
本研究纳入了16名健康受试者（9名男性，年龄范围25 - 40岁）。通过3T MRI扫描仪获取形态学和扩散数据。使用基于概率约束球面反卷积算法的先进纤维束成像技术进行后处理分析。采用双尾Wilcoxon秩和检验进行统计分析。结果指标是视辐射纤维束在不同皮质视觉区域（V1 - V5）的百分比分布。后者通过朱利希概率组织学图谱检测。
平均连通性分析显示，视辐射主要分布在V1（47.46% ± 5.5）和V2（32.45% ± 3.98）；此外，还检测到与V3（7.81 ± 3.06）、V4（4.22% ± 1.82）和V5（8.06% ± 2.65）的直接连接。
在本研究中，通过不受其他纤维束成像技术（如扩散张量成像）限制的算法获得了健康人脑视辐射的连通性概况。有趣的是，首次在人类中检测到与V4的直接连接；此外，还为V5连接的可能存在提供了进一步支持。我们的研究结果显示了外侧膝状体与皮质视觉区域之间的新连接，为导致视觉信号加工的现象提供了进一步的可能理解。
