The anatomy of cerebral achromatopsia: a reappraisal and comparison of two case reports

Abstract

Brain damage can produce acquired deficits of color perception, or cerebral achromatopsia. In these patients, lesions tend to overlap on a restricted region in the ventral occipitotemporal cortex, close to the reported locations of the putative V4 complex and to foci of increased blood-oxygen-level-dependent (BOLD) activity related to color perception in normal participants. Unilateral lesions give rise to achromatopsia in the contralateral visual field (hemiachromatopsia). Here we present a partial English translation of the first case report of a hemiachromatopsic patient with detailed anatomical evidence (Madame R., Verrey, 1888), and discuss these results in relation to a more recent case report (Madame D., Bartolomeo et al., 1997) of a patient with two consecutive hemorrhagic lesions in the occipitotemporal regions of the two hemispheres. Strikingly, Madame D. developed full-field achromatopsia after the second lesion in the right hemisphere, without having shown any signs of hemiachromatopsia after the first lesion in the left hemisphere. Thanks to the comparison of the reconstructed lesion patterns between the two patients and with the putative location of color-related areas in the human brain, we offer a possible, if speculative, account of this puzzling pattern of anatomo-clinical correlations, based on intra- and inter-hemispheric connectivity.

Keywords: Achromatopsia; Brain damage; Color processing; Occipital lobe; Temporal lobe.