Muldal AM, Lillicrap TP, Richards BA, Akerman CJ. Clonal relationships impact neuronal tuning within a phylogenetically ancient vertebrate brain structure.
Curr Biol 2014;
24:1929-33. [PMID:
25127219 PMCID:
PMC4151134 DOI:
10.1016/j.cub.2014.07.015]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023]
Abstract
Understanding how neurons acquire specific response properties is a major goal in neuroscience. Recent studies in mouse neocortex have shown that “sister neurons” derived from the same cortical progenitor cell have a greater probability of forming synaptic connections with one another [1, 2] and are biased to respond to similar sensory stimuli [3, 4]. However, it is unknown whether such lineage-based rules contribute to functional circuit organization across different species and brain regions [5]. 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 [6]. Tectal neurons possess well-defined spatial receptive fields (RFs) whose center positions are retinotopically organized [7]. 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. To test this prediction, we developed a protocol to unambiguously identify the daughter neurons derived from single tectal progenitor cells in Xenopus laevis tadpoles. We combined this approach with in vivo two-photon calcium imaging in order to characterize the RF properties of tectal neurons. Our data reveal that the RF centers of sister neurons are significantly more similar than would be expected by chance. Ontogenetic relationships therefore influence the fine-scale topography of the retinotectal map, indicating that lineage relationships may represent a general and evolutionarily conserved principle that contributes to the organization of neural circuits.
We perform in vivo fate mapping of single progenitors in Xenopus laevis optic tectum
Two-photon calcium imaging reveals similar receptive fields in sister tectal neurons
Clonal relationships influence the fine-scale topography of the retinotectal map
This supports a conserved influence of lineage on neuronal response properties
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