Thwaites Andrew, Wingfield Cai, Wieser Eric, Soltan Andrew, Marslen-Wilson William D, Nimmo-Smith Ian
Department of Psychology, University of Cambridge, Cambridge, UK; MRC Cognition and Brain Sciences Unit, Cambridge, UK.
Department of Psychology, University of Cambridge, Cambridge, UK; Department of Psychology, University of Lancaster, Lancaster, UK.
Vision Res. 2018 Apr;145:1-10. doi: 10.1016/j.visres.2018.01.011. Epub 2018 Apr 12.
In human visual processing, information from the visual field passes through numerous transformations before perceptual attributes such as colour are derived. The sequence of transforms involved in constructing perceptions of colour can be approximated by colour appearance models such as the CIE (2002) colour appearance model, abbreviated as CIECAM02. In this study, we test the plausibility of CIECAM02 as a model of colour processing by looking for evidence of its cortical entrainment. The CIECAM02 model predicts that colour is split in to two opposing chromatic components, red-green and cyan-yellow (termed CIECAM02-a and CIECAM02-b respectively), and an achromatic component (termed CIECAM02-A). Entrainment of cortical activity to the outputs of these components was estimated using measurements of electro- and magnetoencephalographic (EMEG) activity, recorded while healthy subjects watched videos of dots changing colour. We find entrainment to chromatic component CIECAM02-a at approximately 35 ms latency bilaterally in occipital lobe regions, and entrainment to achromatic component CIECAM02-A at approximately 75 ms latency, also bilaterally in occipital regions. For comparison, transforms from a less physiologically plausible model (CIELAB) were also tested, with no significant entrainment found.
在人类视觉处理过程中，来自视野的信息在产生诸如颜色等感知属性之前会经过无数次转换。构建颜色感知所涉及的转换序列可以用颜色外观模型来近似，比如国际照明委员会（2002年）的颜色外观模型，简称为CIECAM02。在本研究中，我们通过寻找其皮层同步化的证据来检验CIECAM02作为颜色处理模型的合理性。CIECAM02模型预测，颜色被分为两个相反的色度成分，即红-绿和青-黄（分别称为CIECAM02-a和CIECAM02-b），以及一个非色度成分（称为CIECAM02-A）。利用脑电图和脑磁图（EMEG）活动的测量来估计皮层活动对这些成分输出的同步化，测量是在健康受试者观看颜色变化的点的视频时进行的。我们发现，在枕叶区域双侧大约35毫秒潜伏期时，皮层活动同步于色度成分CIECAM02-a，在大约75毫秒潜伏期时，也在枕叶区域双侧同步于非色度成分CIECAM02-A。作为比较，我们还测试了一个生理合理性较低的模型（CIELAB）的转换，未发现显著的同步化现象。
