Circadian firing-rate rhythms and light responses of rat habenular nucleus neurons in vivo and in vitro

H. Zhao, B. Rusak

Résultat de recherche: Articleexamen par les pairs

140 Citations (Scopus)

Résumé

The suprachiasmatic nuclei of the anterior hypothalamus serve as the principal pacemaker of the mammalian circadian system. Among its efferent targets are the habenular nucleus (Hb), especially the lateral Hb (LHb), which plays an important role in conveying input from the limbic forebrain to midbrain structures. We recorded extracellularly from single neurons in the LHb and medial Hb (MHb), both in vivo and using an in vitro slice preparation, to assess their responses to retinal illumination and the rhythmicity of their firing rates. Of cells recorded in the LHb, 42% were tonically activated or suppressed by retinal illumination, while significantly fewer cells recorded in the MHb responded to retinal illumination (19%). Of photically responsive cells, 68% in the LHb were activated and the remainder suppressed, while only 25% of those recorded in the MHb were activated. Cells in both the LHb and MHb showed higher baseline firing rates during the day than during the night in vivo, while photic responses were of significantly larger amplitude among LHb cells during the projected night than during the projected day. LHb cells recorded in vitro maintained their rhythmicity for two circadian cycles, but MHb cells did not show a rhythm in vitro. The habenula may play a role in linking circadian and motivational systems and may contribute to photic regulation of these systems, as well as to the rhythmicity of their function.

Langue d'origineEnglish
Pages (de-à)519-528
Nombre de pages10
JournalNeuroscience
Volume132
Numéro de publication2
DOI
Statut de publicationPublished - 2005

Note bibliographique

Funding Information:
We are grateful to Donna Goguen, Debbie Fice, Elliott Marchant and Xiaowei Song for their assistance and advice. This study was supported by grants from CIHR and NSERC of Canada and the National Natural Science Foundation of China (No. 30270502).

ASJC Scopus Subject Areas

  • General Neuroscience

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