Different cortical projections from three subdivisions of the rat lateral posterior thalamic nucleus: a single-neuron tracing study with viral vectors.
The lateral posterior thalamic nucleus (LP) is one of the components of the extrageniculate pathway in the rat visual system, and is cytoarchitecturally divided into three subdivisions--lateral (LPl), rostromedial (LPrm), and caudomedial (LPcm) portions. To clarify the differences in the dendritic fields and axonal arborisations among the three subdivisions, we applied a single-neuron labeling technique with viral vectors to LP neurons. The proximal dendrites of LPl neurons were more numerous than those of LPrm and LPcm neurons, and LPrm neurons tended to have wider dendritic fields than LPl neurons. We then analysed the axonal arborisations of LP neurons by reconstructing the axon fibers in the cortex. The LPl, LPrm and LPcm were different from one another in terms of the projection targets--the main target cortical regions of LPl and LPrm neurons were the secondary and primary visual areas, whereas those of LPcm neurons were the postrhinal and temporal association areas. Furthermore, the principal target cortical layers of LPl neurons in the visual areas were middle layers, but that of LPrm neurons was layer 1. This indicates that LPl and LPrm neurons can be categorised into the core and matrix types of thalamic neurons, respectively, in the visual areas. In addition, LPl neurons formed multiple axonal clusters within the visual areas, whereas the fibers of LPrm neurons were widely and diffusely distributed. It is therefore presumed that these two types of neurons play different roles in visual information processing by dual thalamocortical innervation of the visual areas.
['Nakamura|Hisashi|H|', 'Hioki|Hiroyuki|H|', 'Furuta|Takahiro|T|', 'Kaneko|Takeshi|T|']
D000818:Animals D001369:Axons D002540:Cerebral Cortex D003712:Dendrites D005822:Genetic Vectors D020647:Lateral Thalamic Nuclei D008297:Male D056347:Neuroanatomical Tract-Tracing Techniques D009474:Neurons D051381:Rats D020318:Rats, Long-Evans D017208:Rats, Wistar D012845:Sindbis Virus D014795:Visual Pathways
extrageniculate pathway axonal arborisation single-neuron labeling Sindbis virus lateral posterior nucleus of the thalamus