The lateral posterior thalamic nucleus (LP) is one of the components of the extrageniculate pathway in the rat visual system, and cytoarchitecturally divided into three subdivisions, lateral (LPl), rostromedial (LPrm) and caudomedial potions (LPcm). To clarify differences in the dendritic field and axonal arborization among the three subdivisions, we applied 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 those of LPl neurons. We then analyzed the axonal arborization of LP neurons by reconstructing the axon fibers in the cortex. The main target cortical regions of LPl and LPrm neurons were the secondary and primary visual areas (V2 and V1), whereas those of LPcm neurons were the postrhinal and/or temporal association areas. Furthermore, the principal target cortical layer(s) of LPl neurons in the visual areas was middle layers, but that of LPrm neurons was layer 1. In addition, most LPl neurons formed multiple axonal clusters within the V2 or in the V1 and V2, as opposed to dorsal lateral geniculate nucleus neurons that usually formed a single cluster in the V1. The present study indicates that LPl and LPrm neurons can be categorized to the 'core' and 'matrix' types of thalamic neurons, respectively, and that these neurons play a pivotal role in the visual information processing.