Seiple W, Kupersmith M J, Holopigian K
Department of Ophthalmology, New York University Medical Center, New York 10016, USA.
Int J Neurosci. 1995;80(1-4):173-80. doi: 10.3109/00207459508986099.
We measured contrast processing as a function of spatial and temporal frequency using three measurement techniques: psychophysical thresholds, visual evoked potential (VEP) thresholds and VEP amplitudes. Measurements were made using the same stimulus parameters and on the same group of subjects. The agreement among these functions depended upon the particular spatio-temporal stimulus employed and in general, there were more differences than similarities among these measures. For example, VEP derived functions (both amplitude and threshold) peaked at 4 c/deg, whereas, the psychophysical functions peaked at 1 c/deg. VEP amplitude functions were maximum at > or = 3.5 Hz, whereas both psychophysical and VEP sensitivity were maximum at < or = 2.5 Hz. VEP thresholds were broad and low pass in shape and in contrast, the psychophysical and VEP amplitude functions were band pass. In summary, comparisons among these measures of contrast processing must be made with caution.
心理物理学阈值、视觉诱发电位（VEP）阈值和VEP振幅。测量使用相同的刺激参数并在同一组受试者上进行。这些函数之间的一致性取决于所采用的特定时空刺激，总体而言，这些测量之间的差异多于相似之处。例如，VEP衍生函数（振幅和阈值）在4 c/deg处达到峰值，而心理物理学函数在1 c/deg处达到峰值。VEP振幅函数在≥3.5 Hz时最大，而心理物理学和VEP敏感性在≤2.5 Hz时最大。VEP阈值形状宽泛且为低通，相比之下，心理物理学和VEP振幅函数为带通。总之，在这些对比度处理测量之间进行比较时必须谨慎。
