Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.

Arterial pulsations are known to modulate muscle spindle firing; however, the physiological significance of such synchronised modulation has not been investigated. Unitary recordings were made from 75 human muscle spindle afferents innervating the pretibial muscles. The modulation of muscle spindle...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Ingvars Birznieks, Tjeerd W Boonstra, Vaughan G Macefield
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/dc09475cb40c4222a1c83137d9f726bd
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:dc09475cb40c4222a1c83137d9f726bd
record_format	dspace
spelling	oai:doaj.org-article:dc09475cb40c4222a1c83137d9f726bd2021-11-18T07:21:56ZModulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.1932-620310.1371/journal.pone.0035091https://doaj.org/article/dc09475cb40c4222a1c83137d9f726bd2012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22529975/pdf/?tool=EBIhttps://doaj.org/toc/1932-6203Arterial pulsations are known to modulate muscle spindle firing; however, the physiological significance of such synchronised modulation has not been investigated. Unitary recordings were made from 75 human muscle spindle afferents innervating the pretibial muscles. The modulation of muscle spindle discharge by arterial pulsations was evaluated by R-wave triggered averaging and power spectral analysis. We describe various effects arterial pulsations may have on muscle spindle afferent discharge. Afferents could be "driven" by arterial pulsations, e.g., showing no other spontaneous activity than spikes generated with cardiac rhythmicity. Among afferents showing ongoing discharge that was not primarily related to cardiac rhythmicity we illustrate several mechanisms by which individual spikes may become phase-locked. However, in the majority of afferents the discharge rate was modulated by the pulse wave without spikes being phase locked. Then we assessed whether these influences changed in two physiological conditions in which a sustained increase in muscle sympathetic nerve activity was observed without activation of fusimotor neurones: a maximal inspiratory breath-hold, which causes a fall in systolic pressure, and acute muscle pain, which causes an increase in systolic pressure. The majority of primary muscle spindle afferents displayed pulse-wave modulation, but neither apnoea nor pain had any significant effect on the strength of this modulation, suggesting that the physiological noise injected by the arterial pulsations is robust and relatively insensitive to fluctuations in blood pressure. Within the afferent population there was a similar number of muscle spindles that were inhibited and that were excited by the arterial pulse wave, indicating that after signal integration at the population level, arterial pulsations of opposite polarity would cancel each other out. We speculate that with close-to-threshold stimuli the arterial pulsations may serve as an endogenous noise source that may synchronise the sporadic discharge within the afferent population and thus facilitate the detection of weak stimuli.Ingvars BirznieksTjeerd W BoonstraVaughan G MacefieldPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 4, p e35091 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Ingvars Birznieks Tjeerd W Boonstra Vaughan G Macefield Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
description	Arterial pulsations are known to modulate muscle spindle firing; however, the physiological significance of such synchronised modulation has not been investigated. Unitary recordings were made from 75 human muscle spindle afferents innervating the pretibial muscles. The modulation of muscle spindle discharge by arterial pulsations was evaluated by R-wave triggered averaging and power spectral analysis. We describe various effects arterial pulsations may have on muscle spindle afferent discharge. Afferents could be "driven" by arterial pulsations, e.g., showing no other spontaneous activity than spikes generated with cardiac rhythmicity. Among afferents showing ongoing discharge that was not primarily related to cardiac rhythmicity we illustrate several mechanisms by which individual spikes may become phase-locked. However, in the majority of afferents the discharge rate was modulated by the pulse wave without spikes being phase locked. Then we assessed whether these influences changed in two physiological conditions in which a sustained increase in muscle sympathetic nerve activity was observed without activation of fusimotor neurones: a maximal inspiratory breath-hold, which causes a fall in systolic pressure, and acute muscle pain, which causes an increase in systolic pressure. The majority of primary muscle spindle afferents displayed pulse-wave modulation, but neither apnoea nor pain had any significant effect on the strength of this modulation, suggesting that the physiological noise injected by the arterial pulsations is robust and relatively insensitive to fluctuations in blood pressure. Within the afferent population there was a similar number of muscle spindles that were inhibited and that were excited by the arterial pulse wave, indicating that after signal integration at the population level, arterial pulsations of opposite polarity would cancel each other out. We speculate that with close-to-threshold stimuli the arterial pulsations may serve as an endogenous noise source that may synchronise the sporadic discharge within the afferent population and thus facilitate the detection of weak stimuli.
format	article
author	Ingvars Birznieks Tjeerd W Boonstra Vaughan G Macefield
author_facet	Ingvars Birznieks Tjeerd W Boonstra Vaughan G Macefield
author_sort	Ingvars Birznieks
title	Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
title_short	Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
title_full	Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
title_fullStr	Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
title_full_unstemmed	Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
title_sort	modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/dc09475cb40c4222a1c83137d9f726bd
work_keys_str_mv	AT ingvarsbirznieks modulationofhumanmusclespindledischargebyarterialpulsationsfunctionaleffectsandconsequences AT tjeerdwboonstra modulationofhumanmusclespindledischargebyarterialpulsationsfunctionaleffectsandconsequences AT vaughangmacefield modulationofhumanmusclespindledischargebyarterialpulsationsfunctionaleffectsandconsequences
_version_	1718423566983102464

Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.

Ejemplares similares