TY - JOUR
T1 - Altered balance of receptive field excitation and suppression in visual cortex of amblyopic macaque monkeys
AU - Hallum, Luke E.
AU - Shooner, Christopher
AU - Kumbhani, Romesh D.
AU - Kelly, Jenna G.
AU - García-Marín, Virginia
AU - Majaj, Najib J.
AU - Anthony Movshon, J.
AU - Kiorpes, Lynne
N1 - Funding Information:
This work was supported by the National Institutes of Health (Grant EY05864 to L.K. and Grant EY22428 to J.A.M., and National Center for Research Resources Grant RR00166 to the Washington National Primate Research Center). We thank Michael Gorman for assistance rearing and behaviorally testing animals, Corey Ziemba for help during experiments, Adam Kohn who helped pilot array recordings in visually normal macaques, and Bob Shapley for comments on the drafted manuscript.
Publisher Copyright:
Copyright © 2017 the Authors.
PY - 2017/8/23
Y1 - 2017/8/23
N2 - In amblyopia, a visual disorder caused by abnormal visual experience during development, the amblyopic eye (AE) loses visual sensitivity whereas the fellow eye (FE) is largely unaffected. Binocular vision in amblyopes is often disrupted by interocular suppression. We used 96-electrode arrays to record neurons and neuronal groups in areas V1 and V2 of six female macaque monkeys (Macaca nemestrina) made amblyopic by artificial strabismus or anisometropia in early life, as well as two visually normal female controls. To measure suppressive binocular interactions directly, we recorded neuronal responses to dichoptic stimulation. We stimulated both eyes simultaneously with large sinusoidal gratings, controlling their contrast independently with raised-cosine modulators of different orientations and spatial frequencies. We modeled each eye’s receptive field at each cortical site using a difference of Gaussian envelopes and derived estimates of the strength of central excitation and surround suppression. We used these estimates to calculate ocular dominance separately for excitation and suppression. Excitatory drive from the FE dominated amblyopic visual cortex, especially in more severe amblyopes, but suppression from both the FE and AEs was prevalent in all animals. This imbalance created strong interocular suppression in deep amblyopes: increasing contrast in the AE decreased responses at binocular cortical sites. These response patterns reveal mechanisms that likely contribute to the interocular suppression that disrupts vision in amblyopes.
AB - In amblyopia, a visual disorder caused by abnormal visual experience during development, the amblyopic eye (AE) loses visual sensitivity whereas the fellow eye (FE) is largely unaffected. Binocular vision in amblyopes is often disrupted by interocular suppression. We used 96-electrode arrays to record neurons and neuronal groups in areas V1 and V2 of six female macaque monkeys (Macaca nemestrina) made amblyopic by artificial strabismus or anisometropia in early life, as well as two visually normal female controls. To measure suppressive binocular interactions directly, we recorded neuronal responses to dichoptic stimulation. We stimulated both eyes simultaneously with large sinusoidal gratings, controlling their contrast independently with raised-cosine modulators of different orientations and spatial frequencies. We modeled each eye’s receptive field at each cortical site using a difference of Gaussian envelopes and derived estimates of the strength of central excitation and surround suppression. We used these estimates to calculate ocular dominance separately for excitation and suppression. Excitatory drive from the FE dominated amblyopic visual cortex, especially in more severe amblyopes, but suppression from both the FE and AEs was prevalent in all animals. This imbalance created strong interocular suppression in deep amblyopes: increasing contrast in the AE decreased responses at binocular cortical sites. These response patterns reveal mechanisms that likely contribute to the interocular suppression that disrupts vision in amblyopes.
KW - Anisometropia
KW - Binocular interaction
KW - Development
KW - Interocular perceptual suppression
KW - Strabismus
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U2 - 10.1523/jneurosci.0449-17.2017
DO - 10.1523/jneurosci.0449-17.2017
M3 - Article
C2 - 28743725
AN - SCOPUS:85029167427
SN - 0270-6474
VL - 37
SP - 8216
EP - 8226
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 34
ER -