Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.

The circadian pacemaker of the suprachiasmatic nuclei (SCN) contains a major pacemaker for 24 h rhythms that is synchronized to the external light-dark cycle. In response to a shift in the external cycle, neurons of the SCN resynchronize with different pace. We performed electrical activity recordin...

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Autores principales:	Jos H T Rohling, Henk Tjebbe vanderLeest, Stephan Michel, Mariska J Vansteensel, Johanna H Meijer
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2011
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/dec60b3468f6490e85f571f0475f314f
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spelling	oai:doaj.org-article:dec60b3468f6490e85f571f0475f314f2021-11-04T06:07:56ZPhase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.1932-620310.1371/journal.pone.0025437https://doaj.org/article/dec60b3468f6490e85f571f0475f314f2011-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21966529/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203The circadian pacemaker of the suprachiasmatic nuclei (SCN) contains a major pacemaker for 24 h rhythms that is synchronized to the external light-dark cycle. In response to a shift in the external cycle, neurons of the SCN resynchronize with different pace. We performed electrical activity recordings of the SCN of rats in vitro following a 6 hour delay of the light-dark cycle and observed a bimodal electrical activity pattern with a shifted and an unshifted component. The shifted component was relatively narrow as compared to the unshifted component (2.2 h and 5.7 h, respectively). Curve fitting and simulations predicted that less than 30% of the neurons contribute to the shifted component and that their phase distribution is small. This prediction was confirmed by electrophysiological recordings of neuronal subpopulations. Only 25% of the neurons exhibited an immediate shift in the phase of the electrical activity rhythms, and the phases of the shifted subpopulations appeared significantly more synchronized as compared to the phases of the unshifted subpopulations (p<0.05). We also performed electrical activity recordings of the SCN following a 9 hour advance of the light-dark cycle. The phase advances induced a large desynchrony among the neurons, but consistent with the delays, only 19% of the neurons peaked at the mid of the new light phase. The data suggest that resetting of the central circadian pacemaker to both delays and advances is brought about by an initial shift of a relatively small group of neurons that becomes highly synchronized following a shift in the external cycle. The high degree of synchronization of the shifted neurons may add to the ability of this group to reset the pacemaker. The large desynchronization observed following advances may contribute to the relative difficulty of the circadian system to respond to advanced light cycles.Jos H T RohlingHenk Tjebbe vanderLeestStephan MichelMariska J VansteenselJohanna H MeijerPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 6, Iss 9, p e25437 (2011)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Jos H T Rohling Henk Tjebbe vanderLeest Stephan Michel Mariska J Vansteensel Johanna H Meijer Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
description	The circadian pacemaker of the suprachiasmatic nuclei (SCN) contains a major pacemaker for 24 h rhythms that is synchronized to the external light-dark cycle. In response to a shift in the external cycle, neurons of the SCN resynchronize with different pace. We performed electrical activity recordings of the SCN of rats in vitro following a 6 hour delay of the light-dark cycle and observed a bimodal electrical activity pattern with a shifted and an unshifted component. The shifted component was relatively narrow as compared to the unshifted component (2.2 h and 5.7 h, respectively). Curve fitting and simulations predicted that less than 30% of the neurons contribute to the shifted component and that their phase distribution is small. This prediction was confirmed by electrophysiological recordings of neuronal subpopulations. Only 25% of the neurons exhibited an immediate shift in the phase of the electrical activity rhythms, and the phases of the shifted subpopulations appeared significantly more synchronized as compared to the phases of the unshifted subpopulations (p<0.05). We also performed electrical activity recordings of the SCN following a 9 hour advance of the light-dark cycle. The phase advances induced a large desynchrony among the neurons, but consistent with the delays, only 19% of the neurons peaked at the mid of the new light phase. The data suggest that resetting of the central circadian pacemaker to both delays and advances is brought about by an initial shift of a relatively small group of neurons that becomes highly synchronized following a shift in the external cycle. The high degree of synchronization of the shifted neurons may add to the ability of this group to reset the pacemaker. The large desynchronization observed following advances may contribute to the relative difficulty of the circadian system to respond to advanced light cycles.
format	article
author	Jos H T Rohling Henk Tjebbe vanderLeest Stephan Michel Mariska J Vansteensel Johanna H Meijer
author_facet	Jos H T Rohling Henk Tjebbe vanderLeest Stephan Michel Mariska J Vansteensel Johanna H Meijer
author_sort	Jos H T Rohling
title	Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
title_short	Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
title_full	Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
title_fullStr	Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
title_full_unstemmed	Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
title_sort	phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.
publisher	Public Library of Science (PLoS)
publishDate	2011
url	https://doaj.org/article/dec60b3468f6490e85f571f0475f314f
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Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.

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