title: Changes in fiber arrangement in the retinofugal pathway of the turtle Mauremys leprosa: an evolutionarily conserved mechanism.
abstract: In spite of the numerous reports on the optic fiber distribution in the optic nerve and tract of vertebrates, there have been few studies of the visual pathway in reptiles. The arrangement of fibers in the optic nerve and tract of the turtle Mauremys leprosa was studied by placing a small granule of carbocyanine dye (DiI or DiA) in one of the four quadrants of the retina. The labeled fibers were traced through transverse sections of the retinofugal pathway with confocal microscopy. Retinal axons displayed a quadrant-specific order along the optic nerve. However, retinal ganglion cell axons were re-organized as they passed through the chiasmatic region of the optic pathway. In the optic tract, the nasal and temporal fibers remained intermingled, but there was segregation of dorsal from ventral fibers. This re-ordering is similar to that described in other vertebrates, suggesting the existence of an evolutionarily conserved mechanism.
authors.affiliation: Departamento de Biología Celular, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, Badajoz, Spain.
authors.forename: Matías
authors.initials: M
authors.lastname: Hidalgo-Sánchez
authors.forename: Javier
authors.initials: J
authors.lastname: Francisco-Morcillo
authors.forename: Gervasio
authors.initials: G
authors.lastname: Martín-Partido
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002232:Carbocyanines / Q000378:metabolism; D004396:Coloring Agents / Q000378:metabolism; D007839:Functional Laterality / Q000502:physiology*; D009412:Nerve Fibers / Q000378:metabolism; D009900:Optic Nerve / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism; D012160:Retina / Q000166:cytology* / Q000378:metabolism; D014426:Turtles / Q000033:anatomy & histology* / Q000378:metabolism; D014795:Visual Pathways / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism
chemical_list: D002232:Carbocyanines; D004396:Coloring Agents; C072024:carbocyanine dye DiIC12(3)