From sensory periphery to cortex: the architecture of the barrelfield as modified by various early manipulations of the mouse whiskerpad.

The barrelfield is the cortical "map" of the ensemble of vibrissal follicles on the mouse whiskerpad. Earlier, we had shown that the skin of the embryonic whiskerpad, when put in culture before having received its innervation, is capable of producing vibrissal follicles arranged in a pattern similar to that formed in vivo; we had also demonstrated that the destruction of vibrissal follicles, and of the terminals that innervate them, leads to important modifications in the architecture of the barrelfield. Here we report on the architecture of barrelfields made to differ from normal as a consequence of radical modifications produced in the corresponding whiskerpad during gestation and at birth: transplantation of additional whiskerpads; rotations (of 90 degrees and 180 degrees) of one whiskerpad; removal and reimplantation of one whiskerpad; removal of one whiskerpad; and division of the infraorbital nerve. The results of these experiments, in which only the morphological correlates of a sensory cortical map have been studied, strengthen the hypothesis that the role played by the sensory periphery in the establishment of such an entity is, indeed, an important one.