Comprehensive classification of retinal neurons of snakes by single-cell transcriptomics (scRNA-seq) and neural-circuit reconstruction with volume electron microscopy.

• Grant number: 24/16897-4
• Support Opportunities: Research Grants - Young Investigators Grants
• Start date: September 01, 2025
• End date: August 31, 2030
• Field of knowledge: Humanities - Psychology - Physiological Psychology
• Principal Investigator: Einat Hauzman
• Grantee: Einat Hauzman
• Principal researcher abroad: David John Gower
• Institution abroad: Natural History Museum, London, England
• Host Institution: Instituto de Psicologia (IP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Daniela Maria Oliveira Bonci ; Dora Selma Fix Ventura ; Kevin Briggman ; Silke Haverkamp ; Vitor Henrique Corredor

Abstract

The diversity of functions performed by the nervous system depends on the variety of cells that make it up and their specific connectivity patterns for information processing. The vertebrate retina is formed by an organized neural network that is highly conserved in vertebrates, with five classes of neurons. However, specific types of cells within each class of neurons and their signal transmission pathways vary among species, depending on their visual needs, ecology and evolutionary history. In this project, we will investigate the types of neurons and circuitry in the retinas of snakes, a major lineage of vertebrates whose inner retinal features are unknown to science. Based on their fascinating ecomorphological diversity and mysteriously varied retinas, snakes are an ideal system to investigate the diversity and evolution of the types of neurons and visual pathways. We will use two state-of-the-art approaches: i) single-cell/single-nucleus transcriptomics (scRNA-seq/snRNA-seq), for precise and detailed classification of cell types based on gene expression profiles, and ii) comparative analysis of connectomes (detailed maps of neural connections) from high-resolution 3D electron microscopy volume reconstructions. Our comparative analyses will include snake species selected based on their phylogeny, types of retinas and photoreceptors, and ecomorphology, including nocturnal species with duplex retinas (with cones and rods) and diurnal species with "all-cone" retinas (without typical rods), as well as retinas with and without double cones. This highly innovative and audacious project will involve collaboration between researchers from Brazil, the United Kingdom, and Germany, and will provide fundamental gains for the advancement of knowledge in visual neurosciences and research in Brazil and worldwide. (AU)