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Functional Identification of Cortical and Subcortical Areas Associated with the Increase in Muscle Sympathetic Nerve Activity in Obstructive Sleep Apnoea
Author(s) -
Macefield Vaughan,
Fatouleh Rania,
Lundblad Linda,
McKenzie David,
Macey Paul,
Henderson Luke
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.984.17
Subject(s) - medicine , brainstem , pons , wakefulness , functional magnetic resonance imaging , anatomy , electroencephalography , radiology , psychiatry
Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnoea (OSA) during daytime wakefulness, leading to hypertension. By recording MSNA concurrently with functional Magnetic Resonance Imaging (fMRI) we aimed to identify the central processes responsible for the sympathoexcitation. Spontaneous fluctuations in MSNA were recorded via tungsten microelectrodes inserted into the peroneal nerve in 17 OSA patients and 15 age‐matched controls while lying in a 3T MRI scanner. Blood Oxygen Level Dependent (BOLD) contrast gradient echo, echo‐planar images were continuously collected in a 4 s ON, 4 s OFF protocol. Fluctuations in BOLD signal intensity covaried with the intensity of the concurrently recorded bursts of MSNA. Signal intensity in the dorsolateral PFC, medial PFC, dorsal precuneus, anterior cingulate cortex, retrosplenial cortex and caudate nucleus was higher in OSA than in controls, while in the RVLM, dorsolateral pons and medullary raphe it was lower. All of these changes were reversed following 6 months of continuous positive airway pressure, which caused a significant fall in MSNA. We conclude that the elevated MSNA in OSA results from functional changes within suprabulbar regions known to be directly or indirectly involved in the modulation of sympathetic outflow via the brainstem, as well as from functional changes within the brainstem itself.