TY - JOUR
T1 - Optical imaging of visually evoked responses in the middle temporal area after deactivation of primary visual cortex in adult primates
AU - Collins, Christine E.
AU - Xu, Xiangmin
AU - Khaytin, Ilya
AU - Kaskan, Peter M.
AU - Casagrande, Vivien A.
AU - Kaas, Jon H.
PY - 2005/4/12
Y1 - 2005/4/12
N2 - The middle temporal area (MT) is a visual area in primates with direct and indirect inputs from the primary visual cortex (V1), a role in visual motion perception, and a suggested role in "blindsight." When V1 is deactivated, some studies report continued activation of MT neurons, which has been attributed to an indirect pathway to MT from the superior colliculus. Here we used muscimol to deactivate V1 while optically imaging visually evoked activity in MT in two primates, owl monkeys and galagos, where MT is exposed on the brain surface. The partial loss of V1 inputs abolished all or nearly all evoked activity in the retinotopically matched part of MT. Low levels of activation that persisted in portions of MT that were unstimulated or retinotopically congruent with the blocked portion of V1 appeared to reflect the spread of activity from stimulated to unstimulated parts of MT. Thus, a significant pathway based on the superior colliculus was not demonstrated.
AB - The middle temporal area (MT) is a visual area in primates with direct and indirect inputs from the primary visual cortex (V1), a role in visual motion perception, and a suggested role in "blindsight." When V1 is deactivated, some studies report continued activation of MT neurons, which has been attributed to an indirect pathway to MT from the superior colliculus. Here we used muscimol to deactivate V1 while optically imaging visually evoked activity in MT in two primates, owl monkeys and galagos, where MT is exposed on the brain surface. The partial loss of V1 inputs abolished all or nearly all evoked activity in the retinotopically matched part of MT. Low levels of activation that persisted in portions of MT that were unstimulated or retinotopically congruent with the blocked portion of V1 appeared to reflect the spread of activity from stimulated to unstimulated parts of MT. Thus, a significant pathway based on the superior colliculus was not demonstrated.
KW - Blindsight
KW - Intrinsic connections
KW - Muscimol
KW - V1 lesion
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U2 - 10.1073/pnas.0501762102
DO - 10.1073/pnas.0501762102
M3 - Article
C2 - 15809438
AN - SCOPUS:17244367123
SN - 0027-8424
VL - 102
SP - 5594
EP - 5599
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 15
ER -