Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.

We measured the ability of three macaque monkeys with unilateral removal of primary visual cortex to detect 9 degrees, 200-ms targets presented at random in the upper or lower quadrants of the normal and hemianopic visual fields. The white or variously coloured target could differ from the backgroun...

Popoln opis

Bibliografske podrobnosti
Main Authors: Cowey, A, Stoerig, P
Format: Journal article
Jezik:English
Izdano: 2001
_version_ 1826303462498893824
author Cowey, A
Stoerig, P
author_facet Cowey, A
Stoerig, P
author_sort Cowey, A
collection OXFORD
description We measured the ability of three macaque monkeys with unilateral removal of primary visual cortex to detect 9 degrees, 200-ms targets presented at random in the upper or lower quadrants of the normal and hemianopic visual fields. The white or variously coloured target could differ from the background in both colour and luminance, or in either of them. Blue and red targets were detectable at any luminance contrast, but green and white targets were barely or not at all detectable at and near isoluminance in the hemianopic field. Blue and red targets were better detected than white targets at the same luminance difference. However, when both the target and the background were dynamically luminance-masked, detection in the hemianopic field failed at isoluminance whatever the colour. In addition, the monkeys were unable to discriminate between simultaneously presented red and green or blue and green targets in the hemianopic field when both targets had similar luminance contrast with the background. Two hemianopic patients tested on a subset of the tasks performed similarly to the monkeys. Together, the results indicate that the residual colour-opponent system that survives damage to V1 is involved in the detection of chromatic changes but cannot sustain simultaneous discrimination between pairs of colours.
first_indexed 2024-03-07T06:03:04Z
format Journal article
id oxford-uuid:ece32c84-d70a-415d-a3ce-3b09190e6e7a
institution University of Oxford
language English
last_indexed 2024-03-07T06:03:04Z
publishDate 2001
record_format dspace
spelling oxford-uuid:ece32c84-d70a-415d-a3ce-3b09190e6e7a2022-03-27T11:20:47ZDetection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ece32c84-d70a-415d-a3ce-3b09190e6e7aEnglishSymplectic Elements at Oxford2001Cowey, AStoerig, PWe measured the ability of three macaque monkeys with unilateral removal of primary visual cortex to detect 9 degrees, 200-ms targets presented at random in the upper or lower quadrants of the normal and hemianopic visual fields. The white or variously coloured target could differ from the background in both colour and luminance, or in either of them. Blue and red targets were detectable at any luminance contrast, but green and white targets were barely or not at all detectable at and near isoluminance in the hemianopic field. Blue and red targets were better detected than white targets at the same luminance difference. However, when both the target and the background were dynamically luminance-masked, detection in the hemianopic field failed at isoluminance whatever the colour. In addition, the monkeys were unable to discriminate between simultaneously presented red and green or blue and green targets in the hemianopic field when both targets had similar luminance contrast with the background. Two hemianopic patients tested on a subset of the tasks performed similarly to the monkeys. Together, the results indicate that the residual colour-opponent system that survives damage to V1 is involved in the detection of chromatic changes but cannot sustain simultaneous discrimination between pairs of colours.
spellingShingle Cowey, A
Stoerig, P
Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.
title Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.
title_full Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.
title_fullStr Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.
title_full_unstemmed Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.
title_short Detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans.
title_sort detection and discrimination of chromatic targets in hemianopic macaque monkeys and humans
work_keys_str_mv AT coweya detectionanddiscriminationofchromatictargetsinhemianopicmacaquemonkeysandhumans
AT stoerigp detectionanddiscriminationofchromatictargetsinhemianopicmacaquemonkeysandhumans