Efferent Projections of Prokineticin 2 Expressing Neurons in the Mouse Suprachiasmatic Nucleus

The suprachiasmatic nucleus (SCN) in the hypothalamus is the predominant circadian clock in mammals. To function as a pacemaker, the intrinsic timing signal from the SCN must be transmitted to different brain regions. Prokineticin 2 (PK2) is one of the candidate output molecules from the SCN. In this study, we investigated the efferent projections of PK2-expressing neurons in the SCN through a transgenic reporter approach. Using a bacterial artificial chromosome (BAC) transgenic mouse line, in which the enhanced green fluorescence protein (EGFP) reporter gene expression was driven by the PK2 promoter, we were able to obtain an efferent projections map from the EGFP-expressing neurons in the SCN. Our data revealed that EGFP-expressing neurons in the SCN, hence representing some of the PK2-expressing neurons, projected to many known SCN target areas, including the ventral lateral septum, medial preoptic area, subparaventricular zone, paraventricular nucleus, dorsomedial hypothalamic nucleus, lateral hypothalamic area and paraventricular thalamic nucleus. The efferent projections of PK2-expressing neurons supported the role of PK2 as an output molecule of the SCN

Electronic Excitations in hcp 4He\mathrm{^4He} at 61.5 MPa and 4.3 K Studied by Inelastic X-Ray Scattering Spectroscopy

The dynamic structure factor S(→q,ω) of electrons in solid 4He was measured with 1.6 eV energy resolution by means of inelastic scattering of synchrotron x rays from a hcp single crystal for →q along the c axis and for q=0.45,0.97,and1.24a.u. The hcp crystal was grown in situ at 61.5 MPa and 4.3 K. A q-independent energy loss peak at 21.9±0.3eV could unambiguously be identified. These signals are the first directly measured electronic excitations in solid helium. They are discussed in terms of excitonic excitations