title: Light-dependent development of asymmetry in the ipsilateral and contralateral thalamofugal visual projections of the chick.
abstract: Light-exposure of the chick embryo induces development of asymmetry in the thalamofugal visual projections to the Wulst regions of the forebrain since the embryo is turned so that it occludes its left and not its right eye. This asymmetry can be reversed by occluding the embryo's right eye and exposing its left eye to light. Here we show that three sub-regions of the thalamus (two in the dorsolateral anterior thalami (DLA) and one more caudal) have differing asymmetries of contralateral and/or ipsilateral projections. Hence the effect of asymmetrical light stimulation is regionally specific within the thalamus. Lateralised light stimulation appears to promote the development of ipsilateral projections from DLA pars dorsolateralis pars anterioris and contralateral projections from the caudal regions (the nucleus superficialis parvocellularis especially) but it may suppress the development of contralateral projections from the nucleus dorsolateralis anterior thalami pars lateralis rostralis. We also show that the light stimulation causes lateralised expression of c-fos and receptors for neurotransmitters.
authors.affiliation: Division of Biochemistry and Cellular Biology, National Institute of Neuroscience, NCNP, Tokyo 187-8502, Japan.
authors.forename: Mamiko
authors.initials: M
authors.lastname: Koshiba
authors.forename: Shun
authors.initials: S
authors.lastname: Nakamura
authors.forename: Chao
authors.initials: C
authors.lastname: Deng
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Rogers
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D007839:Functional Laterality / Q000502:physiology / Q000528:radiation effects*; D008027:Light; D009473:Neuronal Plasticity / Q000502:physiology / Q000528:radiation effects; D010775:Photic Stimulation; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism / Q000528:radiation effects; D011978:Receptors, Nicotinic / Q000378:metabolism / Q000528:radiation effects; D012683:Sensory Deprivation / Q000502:physiology; D013687:Telencephalon / Q000166:cytology / Q000196:embryology / Q000254:growth & development* / Q000528:radiation effects*; D013788:Thalamus / Q000166:cytology / Q000196:embryology / Q000254:growth & development* / Q000528:radiation effects*; D014795:Visual Pathways / Q000196:embryology / Q000254:growth & development* / Q000528:radiation effects*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D011978:Receptors, Nicotinic