Visually evoked responses in extrastriate area MT after lesions of striate cortex in early life

Lesions of striate cortex [primary visual cortex (V1)] in adult primates result in blindness. In contrast, V1 lesions in neonates typically allow much greater preservation of vision, including, in many human patients, conscious perception. It is presently unknown how this marked functional differenc...

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Bibliographic Details
Published in:The Journal of neuroscience 2013-07, Vol.33 (30), p.12479-12489
Main Authors: Yu, Hsin-Hao, Chaplin, Tristan A, Egan, Gregory W, Reser, David H, Worthy, Katrina H, Rosa, Marcello G P
Format: Article
Language:English
Subjects:
Age Factors
Animals
Blindness, Cortical - physiopathology
Brain Mapping
Callithrix
Denervation
Electrophysiology
Evoked Potentials, Visual - physiology
Female
Male
Models, Neurological
Photic Stimulation - methods
Primates
Scotoma - physiopathology
Signal-To-Noise Ratio
Visual Cortex - growth & development
Visual Cortex - physiology
Visual Fields - physiology
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Summary:Lesions of striate cortex [primary visual cortex (V1)] in adult primates result in blindness. In contrast, V1 lesions in neonates typically allow much greater preservation of vision, including, in many human patients, conscious perception. It is presently unknown how this marked functional difference is related to physiological changes in cortical areas that are spared by the lesions. Here we report a study of the middle temporal area (MT) of adult marmoset monkeys that received unilateral V1 lesions within 6 weeks of birth. In contrast with observations after similar lesions in adult monkeys, we found that virtually all neurons in the region of MT that was deprived of V1 inputs showed robust responses to visual stimulation. These responses were very similar to those recorded in neurons with receptive fields outside the lesion projection zones in terms of firing rate, signal-to-noise ratio, and latency. In addition, the normal retinotopic organization of MT was maintained. Nonetheless, we found evidence of a very specific functional deficit: direction selectivity, a key physiological characteristic of MT that is known to be preserved in many cells after adult V1 lesions, was absent. These results demonstrate that lesion-induced reorganization of afferent pathways is sufficient to develop robust visual function in primate extrastriate cortex, highlighting a likely mechanism for the sparing of vision after neonatal V1 lesions. However, they also suggest that interactions with V1 in early postnatal life are critical for establishing stimulus selectivity in MT.
ISSN:0270-6474
1529-2401
1529-2401
DOI:10.1523/jneurosci.0844-13.2013