In the article “Spatiotemporal Dynamics of Sensory Responses in Layer 2/3 of Rat Barrel Cortex Measured In Vivo by Voltage-Sensitive Dye Imaging Combined with Whole-Cell Voltage Recordings and Neuron Reconstructions,” by Carl C. H. Petersen, Amiram Grinvald, and Bert Sakmann, which appeared on pages 1298-1309 of the February 15, 2003 issue, not all of the neurons shown in the superposition of Figure 5 have the soma located in the D2 barrel. The idealized barrel maps should be annotated with the row and arc axes, without specific reference to individual barrel names. In the bottom left panel, the superposition of axons was not correctly centered. They were mistakenly shifted ∼50 μm upward toward the C row relative to the idealized barrel map. These corrections do not affect the quantitation or conclusion that axons predominantly spread along the row orientation of the barrel map.