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Structural and functional composition of the developing retinogeniculate pathway in the mouse
- Source :
- Visual neuroscience. 22(5)
- Publication Year :
- 2005
-
Abstract
- The advent of transgenic mice has made the developing retinogeniculate pathway a model system for targeting potential mechanisms that underlie the refinement of sensory connections. However, a detailed characterization of the form and function of this pathway is lacking. Here we use a variety of anatomical and electrophysiological techniques to delineate the structural and functional changes occurring in the lateral geniculate nucleus (LGN) of dorsal thalamus of the C57/BL6 mouse. During the first two postnatal weeks there is an age-related recession in the amount of terminal space occupied by retinal axons arising from the two eyes. During the first postnatal week, crossed and uncrossed axons show substantial overlap throughout most of the LGN. Between the first and second week retinal arbors show significant pruning, so that by the time of natural eye opening (P12–14) segregation is complete and retinal projections are organized into distinct eye-specific domains. During this time of rapid anatomical rearrangement, LGN cells could be readily distinguished using immunocytochemical markers that stain for NMDA receptors, GABA receptors, L-type Ca2+channels, and the neurofilament protein SMI-32. Moreover, the membrane properties and synaptic responses of developing LGN cells are remarkably stable and resemble those of mature neurons. However, there are some notable developmental changes in synaptic connectivity. At early ages, LGN cells are binocularly responsive and receive input from as many as 11 different retinal ganglion cells. Optic tract stimulation also evokes plateau-like depolarizations that are mediated by the activation of L-type Ca2+channels. As retinal inputs from the two eyes segregate into nonoverlapping territories, there is a loss of binocular responsiveness, a decrease in retinal convergence, and a reduction in the incidence of plateau potentials. These data serve as a working framework for the assessment of phenotypes of genetically altered strains as well as provide some insight as to the molecular mechanisms underlying the refinement of retinogeniculate connections.
- Subjects :
- Aging
Patch-Clamp Techniques
genetic structures
Optic tract
Calcium Channels, L-Type
Physiology
Biology
Lateral geniculate nucleus
Retinal ganglion
Receptors, N-Methyl-D-Aspartate
Retina
chemistry.chemical_compound
Mice
Plateau potentials
Receptors, GABA
Neural Pathways
medicine
Animals
Visual Pathways
Geniculate Bodies
Retinal
Immunohistochemistry
Sensory Systems
Axons
Retinal waves
Electrophysiology
Mice, Inbred C57BL
medicine.anatomical_structure
chemistry
Synapses
Female
sense organs
Neuroscience
Subjects
Details
- ISSN :
- 09525238
- Volume :
- 22
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- Visual neuroscience
- Accession number :
- edsair.doi.dedup.....5ae06faf660db27ba00c79df867fcd62