Clonal relationships impact neuronal tuning within a phylogenetically ancient vertebrate brain structure.
Bottom Line: To address this question, we examined the influence of lineage on the response properties of neurons within the optic tectum, a visual brain area found in all vertebrates.If lineage relationships do not influence the functional properties of tectal neurons, one prediction is that the RF positions of sister neurons should be no more (or less) similar to one another than those of neighboring control neurons.Our data reveal that the RF centers of sister neurons are significantly more similar than would be expected by chance.
Affiliation: Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.Show MeSH
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Mentions: To reveal the architecture of the tectum and to probe the functional properties of tectal neurons, we then injected the calcium indicator dye Oregon Green BAPTA1-AM (OGB1-AM) into the region encompassing the dextran-labeled neurons. Images taken before and after the OGB1-AM injection enabled us to confirm 45 animals in which the dextran-labeled neurons could still be clearly distinguished, and the different tectal layers were clearly demarcated [12, 13] (Figure 2A). Each clone was comprised of 2–7 fluorescently labeled neurons. The majority of clones (25 out of 45; 56%) spanned multiple cell-dense layers of the tectum, and, in the remainder (20 out of 45; 44%), the neurons were restricted to the same layer (Figure 2B). Across all clones, there was a strong tendency for neurons derived from the same progenitor to be situated within nearby cell-dense layers (p < 2 × 10−5, bootstrap test; Figure 2C; Supplemental Experimental Procedures).
Affiliation: Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK.