Clonal relationships impact neuronal tuning within a phylogenetically ancient vertebrate brain structure

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Systems Neuroscience

Background:

• Understanding how neurons develop specific response properties is crucial for neuroscience.
• Studies in mice suggest sister neurons, originating from the same progenitor, connect and respond similarly.
• It remains unclear if these lineage-based rules apply across species and brain regions.

Purpose of the Study:

• To investigate the influence of neuronal lineage on response properties in the optic tectum, a key visual center in vertebrates.
• To determine if sister neurons in the optic tectum exhibit similar receptive field (RF) properties.
• To test if lineage relationships contribute to the fine-scale organization of the retinotectal map.

Main Methods:

• Developed a novel protocol to identify daughter neurons from single tectal progenitor cells in Xenopus laevis tadpoles.
• Utilized in vivo two-photon calcium imaging to record neural activity and characterize RF properties.
• Compared the RF similarity of sister neurons to that of neighboring control neurons.

Main Results:

• Sister neurons in the optic tectum exhibited significantly more similar receptive field center positions than predicted by chance.
• This similarity was greater than observed between neighboring, non-sister neurons.
• Lineage relationships demonstrably influence the precise spatial organization of the retinotectal map.

Conclusions:

• Neuronal lineage is a significant factor in organizing neural circuits beyond the neocortex.
• The findings suggest that lineage-based rules for neural circuit organization are evolutionarily conserved across vertebrates.
• Ontogenetic relationships play a role in establishing the functional topography of sensory maps, such as the retinotectal map.