Correction: In the article “Regulation of Dendritic Spine Density in Cultured Rat Hippocampal Neurons by Steroid Hormones” (Diane D. Murphy and Menahem Segal), which appeared on pages 4059–4068 in the July 1, 1996 issue, the authors would like to correct the following error. A mistake was discovered in the presentation of the error bars in Figures 2, 3, 4, 5, 6. The correct SEMs are as follows, from left to right: Fig. 2: 0.568, 0.92, 0.285, 0.443, 0.871. Fig. 3: 0.288, 0.524, 0.247, 0.25, 0.288, 0.375. Fig. 4: 0.422, 0.345, 0.436, 0.361, 0.394. Fig. 5: 0.372, 0.492, 0.408, 0.643, 0.341, 0.344, 0.139, 0.507. Fig. 6: 0.292, 0.463, 0.256, 0.188, 0.23, 0.457, 0.423, 0.426.
