Blockade of retinal or cortical activity does not prevent the development of callosal patches normally associated with ocular dominance columns in primary visual cortex
Autor: | Robyn J. Laing, Jaime F. Olavarria, Hsueh Chung Lu |
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Jazyk: | angličtina |
Rok vydání: | 2021 |
Předmět: |
medicine.medical_specialty
genetic structures Physiology Enucleation Biology Brief Communication Corpus Callosum columnar organization chemistry.chemical_compound Cortex (anatomy) Ophthalmology Primary Visual Cortex medicine Animals Rats Long-Evans Visual Cortex tetrodotoxin Retinal segregation Sensory Systems Rats Ganglion Blockade Dominance Ocular medicine.anatomical_structure Visual cortex Long Evans rats chemistry Tetrodotoxin interhemispheric connections Ocular dominance column |
Zdroj: | Visual Neuroscience |
ISSN: | 1469-8714 0952-5238 |
Popis: | Callosal patches in primary visual cortex of Long Evans rats, normally associated with ocular dominance columns, emerge by postnatal day 10 (P10), but they do not form in rats monocularly enucleated a few days before P10. We investigated whether we could replicate the results of monocular enucleation by using tetrodotoxin (TTX) to block neural activity in one eye, or in primary visual cortex. Animals received daily intravitreal (P6–P9) or intracortical (P7–P9) injections of TTX, and our physiological evaluation of the efficacy of these injections indicated that the blockade induced by a single injection lasted at least 24 h. Four weeks later, the patterns of callosal connections in one hemisphere were revealed after multiple injections of horseradish peroxidase in the other hemisphere. We found that in rats receiving either intravitreal or cortical injections of TTX, the patterns of callosal patches analyzed in tangential sections from the flattened cortex were not significantly different from the pattern in normal rats. Our findings, therefore, suggest that the effects of monocular enucleation on the distribution of callosal connections are not due to the resulting imbalance of afferent ganglion cell activity, and that factors other than neural activity are likely involved. |
Databáze: | OpenAIRE |
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