fMRI activation of LGN and visual cortex under photopic, mesopic and scotopic luminance levels.
fMRI activation of LGN and visual cortex under photopic, mesopic and scotopic luminance levels.
复制标题
明视、中视和暗视亮度水平下 LGN 和视觉皮层的 fMRI 激活
DOI：
10.1167/15.12.254
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发表时间：
2015
影响因子：
1.8
通讯作者：
Malania
中科院分区：
文献类型：
--
作者：
Greenlee;Siebertz;Rosengarth;Malania
我们调查是否fMRI BOLD反应的视觉通路依赖于光适应水平。12名视力正常的参与者（4名男性，8名女性;年龄21-41岁）进行了功能性磁共振成像（fMRI）测量暗视，中间视觉和明视亮度水平。视觉刺激由以8Hz闪烁的30度径向棋盘刺激组成。刺激以区组设计呈现（12 s刺激，12 s基线）。通过应用2至6个中性密度滤光片（透射率13%）实现明视、中间视和暗视亮度水平，分别产生43（明视）、0.73（中间视）或0.01（暗视）cd/m2的最大亮度。暗适应受试者报告了在中间视觉条件下感知颜色的浦肯野移位和在暗视条件下完全没有颜色感知。使用3 T扫描仪（Siemens Allegra）进行fMRI测量。使用T2* 加权梯度回波平面成像序列（TR= 2s，TE= 30 ms，FA= 90）采集功能图像，该序列由34个横向切片组成（体素大小= 2.5 x 2.5 x 2.5 mm; FoV= 160 x 160 mm）。用SPM 8软件进行数据分析。将图像标准化为丘脑图谱（Krauth等人，2010，Neuroimage，49，2053-2062）。对LGN的基于图谱的大（M）和小细胞（P）体素进行ROI分析。对LGN的BOLD信号中的信号变化百分比进行2（半球）x 3（亮度水平）x 2（M/P ROI）重复测量ANOVA。结果显示亮度水平的显著主效应（随着亮度降低，BOLD响应降低; p<. 001)亮度条件与感兴趣区域之间存在显著的交互作用（M/P; p=. 001）。与早期的研究（Hadjikhani & Tootell，2000，Human Brain Mapping，9，55-63）一致，在视网膜定位定义的V1中，我们发现对于暗视亮度水平，在中央凹的投影区中没有激活。
We investigated whether the fMRI BOLD response in the visual pathway depends on the light adaptation level. Twelve normal-sighted participants (4 males, 8 females; age 21-41 years) with functional magnetic resonance imaging (fMRI) were measured under scotopic, mesopic and photopic luminance levels. The visual stimulation consisted of a 30-degree radial checkerboard stimulus flickering at 8 Hz. The stimuli were presented in a block design (12 s stimulation, 12 s baseline). Photopic, mesopic and scotopic luminance levels were achieved by applying 2 to 6 neutral density filters (transmission 13%) resulting in a maximal luminance of 43 (photopic), 0.73 (mesopic) or 0.01 (scotopic) cd/m 2, respectively. Dark-adapted subjects reported a Purkinje-shift in perceived colors under mesopic conditions and the total absence of color perception under scotopic conditions. fMRI measurements were conducted using a 3T scanner (Siemens Allegra). Functional images were acquired with a T2*-weighted gradient echo planar imaging sequence (TR= 2s, TE= 30 ms, FA= 90) consisting of 34 transverse slices (voxel size= 2.5 x 2.5 x 2.5 mm; FoV= 160 x 160 mm). Data analysis was performed with SPM8. Images were normalized to the Thalamus Atlas (Krauth et al., 2010, Neuroimage, 49, 2053-2062). ROI-analysis was conducted on the atlas-based magno (M)-and parvocellular (P) voxels of the LGN. A 2 (hemispheres) x 3 (luminance levels) x 2 (M/P ROIs) repeated-measurements ANOVA was conducted on the percent signal changes in the BOLD signal for the LGN. Results show a significant main effect of luminance level (decreasing BOLD response with decreasing luminance; p<. 001) and a significant interaction between luminance condition and ROI (M/P; p=. 001). In agreement with an earlier study (Hadjikhani & Tootell, 2000, Human Brain Mapping, 9, 55–63), in retinotopically defined V1 we found no activation in the projection zone of the fovea for the scotopic luminance level.