Heywood C A, Gaffan D, Cowey A
Department of Experimental Psychology, University of Oxford, UK.
Eur J Neurosci. 1995 May 1;7(5):1064-73. doi: 10.1111/j.1460-9568.1995.tb01093.x.
In human cerebral achromatopsia, extrastriate cortical damage produces a severe or complete loss of colour vision, with relative sparing of non-chromatic vision. The critical lesion appears to be in a medial occipito-temporal area, occupying the lingual and caudal fusiform gyri; positron emission tomography has shown that this cortical region is one of several activated in normal human observers during colour vision tasks. Attempts to find an analogous 'colour centre' in the cortex of monkeys have not been successful. In particular, ablation of cortical area V4, sometimes thought on physiological grounds to be more involved in wavelength and colour coding than any other visual cortical area, produces only mild impairments in colour discrimination. In the present study we tested the colour vision of monkeys after cortical ablations that mainly or entirely spared area V4. One group of monkeys (group AT) received ablations in the temporal lobe anterior to area V4, and a second group (group MOT) received ablations in a medial occipito-temporal area roughly corresponding in cranial location to the lesion that produces human cerebral achromatopsia. The animals in group MOT showed no impairment of their colour vision. Group AT, in contrast, had a severe impairment in chromatic vision, with a relative sparing of non-chromatic vision. Their behaviour was indistinguishable from that of a human patient with total cerebral achromatopsia who had been tested on the same tasks. These results show that area V4 in macaque monkeys is not analogous, and probably not homologous, to the human colour centre. Instead, they suggest that the area of the monkey's brain corresponding to the colour area in the human brain is in the temporal cortex, anterior to area V4.
在人类大脑性全色盲中，纹外皮质损伤会导致严重或完全丧失色觉，而非彩色视觉相对保留。关键病变似乎位于枕颞内侧区域，占据舌回和梭状回尾部；正电子发射断层扫描显示，在正常人类观察者进行色觉任务时，这个皮质区域是被激活的几个区域之一。在猴子的大脑皮质中寻找类似“色觉中枢”的尝试并未成功。特别是，有时基于生理学原因认为皮质V4区比其他任何视觉皮质区更参与波长和颜色编码，切除该区域只会导致颜色辨别能力轻度受损。在本研究中，我们测试了主要或完全保留V4区的皮质切除术后猴子的色觉。一组猴子（AT组）在V4区前方的颞叶进行了切除，另一组猴子（MOT组）在枕颞内侧区域进行了切除，该区域在颅骨位置大致对应于导致人类大脑性全色盲的病变。MOT组的动物色觉没有受损。相比之下，AT组在色觉方面有严重损伤，非彩色视觉相对保留。它们的行为与在相同任务上接受测试的患有完全性大脑性全色盲的人类患者没有区别。这些结果表明，猕猴的V4区与人类色觉中枢不类似，可能也不同源。相反，它们表明猴子大脑中与人类大脑色觉区域相对应的区域位于颞叶皮质，在V4区前方。
