The somatosensory cortex is the main cortical sensory area of rodents, who heavily rely on tactile input from their whiskers to gain information on their surroundings. Two ascending pathways convey information from the whiskers to the cortex. The lemniscal pathway sends inputs to the ventro-posteromedial (VPM) thalamocortical axons, which target neurons in layers Vb and discrete areas of layer IV of somatosensory cortex forming anatomically distinguishable barrels and generating a topographic map of the whisker pad. The paralemniscal pathway involves the posterior medial (POm) nucleus of the thalamus, which projects to layer I and Va of somatosensory and motor cortex. In the present study, I investigate the role of specific inputs in the development of POm thalamocortical projections. The main finding of this study is that interrupting peripheral input during a critical period of development in wild type mice does not affect significantly the connectivity and morphology of the POm projections. I also show that the POm is a heterogeneous nucleus, containing distinct subtypes of projection neurons in anatomically distinct territories. Finally, since the POm also receives strong input from the cerebral cortex, I am assessing in current experiments the role of this descending input in the development of POm thalamocortical connectivity. Together these results demonstrate that the ascending input to the POm nucleus of the thalamus does not play a critical role in the development of POm thalamocortical projections. Instead, the cortical input is more likely to affect the developmental wiring of these projections.