Robson A G, Holder G E, Moreland J D, Kulikowski J J
Visual Sciences Lab, Moffat Building, Faculty of Life Sciences, University of Manchester, PO Box 88, Manchester, UK.
Vis Neurosci. 2006 Mar-Apr;23(2):275-83. doi: 10.1017/S0952523806232115.
To assess the effects of macular pigment optical density (MPOD) on isoluminant stimuli and to quantify MPOD electrophysiologically, MPOD distribution profiles were obtained in normal subjects using minimum motion and minimum flicker photometry. Isoluminance of VEP stimuli was determined using minimum flicker and tritan confusion lines were determined using a minimum distinct border criterion. Onset-offset and reversal VEPs to isoluminant red/green, blue/green, and subject-specific tritan gratings of different diameters were recorded from the same 14 subjects tested psychophysically. VEPs were additionally recorded to annular gratings. Chromatic VEP selectivity was assessed by Fourier analysis and as an index; onset negativity/(onset negativity + onset positivity). Peak MPOD varied between 0.2-0.8. Chromatic onset VEPs to all isoluminant 3-deg fields were predominantly negative. Larger blue/green and tritan stimuli elicited VEPs with additional positive, achromatic components; for 9-deg gratings, peak MPOD showed negative correlation with the power of the VEP fundamental (r = -0.70) and with the selectivity index (r = -0.83). Annular gratings elicited chromatic-specific B/G VEPs but only when isoluminance was determined for the annulus. Chromatic selectivity loss in VEPs to large B/G or Tritan gratings can be used to estimate subject-specific MPOD. An important implication is that isoluminant Tritan stimuli with short-wavelength components must be restricted in size in order to optimize koniocellular selectivity.
为评估黄斑色素光密度（MPOD）对等亮度刺激的影响并通过电生理方法对MPOD进行量化，我们使用最小运动和最小闪烁光度法在正常受试者中获取了MPOD分布曲线。使用最小闪烁法确定VEP刺激的等亮度，使用最小可分辨边界标准确定蓝黄色混淆线。从14名接受心理物理学测试的同一受试者中记录了对不同直径的等亮度红/绿、蓝/绿和受试者特异性蓝黄色光栅的起始-偏移和反转VEP。还记录了对环形光栅的VEP。通过傅里叶分析评估色觉VEP选择性，并将其作为一个指标：起始负波/（起始负波+起始正波）。峰值MPOD在0.2 - 0.8之间变化。对所有等亮度3°视野的色觉起始VEP主要为负波。较大的蓝/绿和蓝黄色刺激引发的VEP带有额外的正性、非彩色成分；对于9°光栅，峰值MPOD与VEP基波功率呈负相关（r = -0.70），与选择性指数呈负相关（r = -0.83）。环形光栅引发了色觉特异性的蓝/绿VEP，但仅当确定环的等亮度时才会出现。对大的蓝/绿或蓝黄色光栅的VEP色觉选择性丧失可用于估计受试者特异性MPOD。一个重要的启示是，为了优化小细胞选择性，必须限制具有短波长成分的等亮度蓝黄色刺激的大小。
