Correction: In the article “A Circadian Clock in the Olfactory Bulb Controls Olfactory Responsivity” by Daniel Granados-Fuentes, Alan Tseng, and Erik D. Herzog, which appeared on pages 12219–12225 of the November 22, 2006 issue, errors were made in describing the effects of olfactory bulbectomy on locomotor activity in mice. In the Abstract (page 12219), the seventh sentence should read “Furthermore, removal of the OB abolished spontaneous circadian cycling of c-Fos in the PC, lengthened the free-running period of locomotor rhythms, and slowed re-entrainment after a 6 h advance and accelerated re-entrainment after a 6 h delay in the light schedule.” In Results, the second paragraph under the section The OB modulates circadian rhythms regulated by the SCN (page 12221), the second and third sentences should read “OBX significantly increased the number of days needed to re-entrain to a 6 h advance in the LD cycle and significantly reduced the time needed to re-entrain to a 6 h delay (Table 1). Consistent with these changes in re-entrainment rates, OBX lengthened the free-running period of locomotor rhythms but did not change the phase angle of entrainment to a 12 h LD cycle.”