Calbindin neurons in the hamster suprachiasmatic nucleus do not exhibit a circadian variation in spontaneous firing rate

Jobst, Erin E; Allen, Charles N.

doi:10.1046/j.1460-9568.2002.02309.x

Cited by 73 publications

(70 citation statements)

References 37 publications

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“…(D) The SCN is composed of functionally distinct cells. In addition to oscillator cells, some cells in the "core" region lack detectable oscillation of clock gene expression and electrical activity (Hamada et al 2001;Jobst and Allen 2002;Karatsoreos et al 2004). Cells of the core and shell region each project to SCN target sites (Abrahamson and Moore 2001;Kriegsfeld et al 2004a).…”

Section: The Tissue Is the Issuementioning

confidence: 99%

“…Both rat AVP cells (Schaap et al 1999) and neurons lying in the AVP-rich region of mouse SCN (delineated by Per1-GFP) (Kuhlman and McMahon 2004) have a higher firing rate during the day than at night. In contrast, calbindin cells of the hamster core SCN (Jobst and Allen 2002) or GRP cells in a transgenic green fluorescent protein (GFP)-reporter mouse (Cloues et al 2001) show no day/night rhythm in firing rate. In summary, at least some core cells are not detectably rhythmic in gene expression or electrical activity but are light responsive during the night.…”

Section: Function Of Scn Subregionsmentioning

confidence: 99%

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Exploring Spatiotemporal Organization of SCN Circuits

Yan

Karatsoreos

LeSauter

et al. 2007

Cold Spring Harbor Symposia on Quantitative Biology

102

111

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Suprachiasmatic nucleus (SCN) neuroanatomy has been a subject of intense interest since the discovery of the SCN's function as a brain clock and subsequent studies revealing substantial heterogeneity of its component neurons. Understanding the network organization of the SCN has become increasingly relevant in the context of studies showing that its functional circuitry, evident in the spatial and temporal expression of clock genes, can be reorganized by inputs from the internal and external environment. Although multiple mechanisms have been proposed for coupling among SCN neurons, relatively little is known of the precise pattern of SCN circuitry. To explore SCN networks, we examine responses of the SCN to various photic conditions, using in vivo and in vitro studies with associated mathematical modeling to study spatiotemporal changes in SCN activity. We find an orderly and reproducible spatiotemporal pattern of oscillatory gene expression in the SCN, which requires the presence of the ventrolateral core region. Without the SCN core region, behavioral rhythmicity is abolished in vivo, whereas low-amplitude rhythmicity can be detected in SCN slices in vitro, but with loss of normal topographic organization. These studies reveal SCN circuit properties required to signal daily time.

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Section: The Tissue Is the Issuementioning

confidence: 99%

Section: Function Of Scn Subregionsmentioning

confidence: 99%

Exploring Spatiotemporal Organization of SCN Circuits

Yan

Karatsoreos

LeSauter

et al. 2007

Cold Spring Harbor Symposia on Quantitative Biology

102

111

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show abstract

“…Although they are all equally part of an anatomically and functionally defined nucleus, SCN neurons are themselves heterogeneous. They differ with respect to the expression of specific neurotransmitters and neuropeptides [21,31], their efferent and afferent connections [1,22], and their neurophysiological firing patterns [14]. In addition, isolated SCN cells express different circadian periods [13,32] and, within the nucleus, different individual cells or groups of cells oscillate with different phases [25,33].…”

Section: Introductionmentioning

confidence: 99%

Development of the mouse suprachiasmatic nucleus: Determination of time of cell origin and spatial arrangements within the nucleus

Kabrita

Davis

2008

Brain Research

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The suprachiasmatic nucleus (SCN) in mammals functions as the principal circadian pacemaker synchronizing diverse physiological and behavioral processes to environmental stimuli. It consists of heterogeneous populations of cells with unique spatial organization that can vary among species, but are commonly discussed within a framework of two principal regions, the ventrolateral or dorsomedial halves of the nucleus or in other instances the core and shell. In both hamsters and rats, cells of different SCN regions have been shown to have different developmental histories. Using bromodeoxyuridine as a marker of cell division, the present study investigated the time of SCN cell origin in mice (C57BL/6) and their settling patterns within the nucleus. Results show that SCN cytogenesis occurs between embryonic days 12 and 15 and is complete 5 days prior to birth. Cells born on embryonic day 12 are mainly confined to a ventrolateral region of the mid-SCN, whereas cells produced later on embryonic days 13.5 and 14.5 form a cap around the cells produced first and extend into the posterior and anterior ends of the nucleus. These results suggest an ordered spatiotemporal program of SCN cytogenesis whereby a mid-SCN core is born first followed by a surrounding shell of later-born cells. Variation in cytogenesis could affect the relative sizes of different SCN regions and, thereby, affect its function. The relative contributions of a highly ordered program of cytogenesis and intercellular interactions after post-mitotic cells leave the germinal epithelium remain to be determined.

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“…pression de ces gènes puis, de proche en proche, la conférait aux neurones adjacents, conduisant ultimement à une expression ubiquitaire de ces gènes dans les NSC, lors du pic. Lorsque les neurones sont suivis individuellement, on s'aperçoit d'ailleurs qu'ils présentent des phases assez variables (c'est-à-dire que le pic des oscillations ne survient pas au même moment), certains neurones étant même complètement déphasés [16,22]; de plus, certaines régions semblent contenir des neurones arythmiques [17,23]. Les NSC fonctionnent donc comme un ensemble très hétérogène, peut-être hiérarchisé: la production des rythmes des NSC en tant que tissu est la résultante d'une moyenne des activités des différents compartiments, voire des milliers d'oscillateurs qui les composent.…”

Section: Brève Histologie Des Nscunclassified