Organization in "barrels" of layer-IV cells of the S1 cortex in the mouse: effects of lesions or deprivation of the mystacial vibrissa]

In newborn mice the mystacial pads of the upper lips were submitted to different destructive or functionally reducing procedures. The effects on the barrels of the somato-sensory cortex were judged in mature animals and classified into 3 categories: 1. the barrels were present and normal; 2. the cortex was devoid of barrel structures; 3. the barrels were disorganized. Only procedures which involved peripheral lesions, and not those which reduced only the functional level, produced effects as deep as absence or disorganization of the barrels.