Retinogeniculate axons undergo eye-specific segregation in the absence of eye-specific layers.
Spontaneous retinal activity mediated by cholinergic transmission regulates the segregation of retinal ganglion cell axons in the lateral geniculate nucleus of the thalamus into eye-specific layers. The details of how the layers form are unknown. Mice lacking the beta2 subunit of the neuronal nicotinic acetylcholine receptor lack ACh-mediated waves and as a result, do not form eye-specific layers at any stage of development. However, during the second postnatal week, beta2-/- mice have glutamate-mediated waves. Here we show that after the first postnatal week, even in the absence of layers, retinothalamic axons segregate into an unlayered, patchy distribution of eye-specific regions. These results indicate that spontaneous neural activity may independently regulate eye-specific segregation and the formation of layers at the developing retinothalamic projection.
Muir-Robinson
Gianna
G
Neurobiology Section, Biology Division, University of California San Diego, La Jolla, California 92093, USA.
Hwang
Bryan J
BJ
Feller
Marla B
MB
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D005829:Geniculate Bodies / Q000166:cytology / Q000254:growth & development*; D007700:Kinetics; D051379:Mice; D018345:Mice, Knockout; D017470:Receptors, Glutamate / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000235:genetics; D012160:Retina / Q000166:cytology / Q000254:growth & development*; D012165:Retinal Ganglion Cells / Q000166:cytology*; D014795:Visual Pathways
D017470:Receptors, Glutamate; D011978:Receptors, Nicotinic