Lichtman laboratory. Tissue was prepared and imaged as previously described with minor modifications EPZ-6438 cell line (Hayworth et al., 2006). For immunoEM, dLGN from postnatal mice were prepared and immunostained with rabbit anti-Iba-1 (Wako) as previously

described (Tremblay et al., 2010b). See Supplemental Experimental Procedures for details. Mice received intraocular injection of cholera toxin-β subunit (CTB) and were sacrificed the following day. Tissue was processed and analyzed as previously described (Jaubert-Miazza et al., 2005 and Stevens et al., 2007). All analyses were performed blind with littermate controls. Array tomography was performed as previously described with minor modifications (Greer et al., 2010, Margolis et al., 2010, Micheva and Smith, 2007, Ross et al., 2010 and Stevens et al., 2007). See Supplemental Experimental Procedures for details. We thank C. Chen, B. Sabatini, M. Tessier-Lavigne, G. Corfas, X. He, Z. He, L. Benowitz, and A. Huberman for their helpful Selleckchem BAY 73-4506 discussions and reading of this manuscript; J. Sanes for the advice

regarding CHX10-tdTomato experiments; J. Lichtman and R. Schalek for the technical expertise regarding EM experiments; E. Polk for performing preliminary engulfment analysis experiments; the imaging core at Children’s Hospital Boston including T. Hill and L. Bu for their technical support; the electron microscopy core at Harvard Medical School including L. Benecchi and M. Ericsson for their technical support; C. Heller for assistance in quantification of data. Work was supported by grants from the Smith Family Foundation (B.S.), Dana Foundation (B.S.), John Merck Scholars Program (B.S.), NINDS (RO1-NS-07100801; B.S.), NRSA

(F32-NS-066698; D.P.S.), NIDA (RO1-DA-15043; B.A.B.), NIH (RO1-NS-045500; M.E.G.), NIH (RO1-NS-32151; R.M.R.), National MS Society (RG4550; R.M.R), NIH (P30-HD-18655; MRDDRC Imaging Core). “
“A major goal of neuroscience is to understand how the nervous system functions at multiple different levels (from genes to neural circuits) to generate behavior. Innate behaviors are particularly attractive to study because they are hardwired into the nervous system and are very similar between individual animals. The control of circadian (∼24 hr) rhythms offers an excellent opportunity to genetically dissect neural circuits because dedicated for clock genes have been identified. This enabled the identification of pacemaker neurons in which clock genes function to modulate multiple innate behaviors, including sleep, courtship, and drug sensitivity (reviewed by Allada and Chung, 2010). Although recent studies have shown the importance of neuronal communication in synchronizing and strengthening molecular and behavioral rhythms (Hogenesch and Herzog, 2011 and Nitabach and Taghert, 2008), the nature of the signals between clock neurons and their effects on neuronal activity are unclear.