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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-2-2
pubmed:abstractText
Generally, women demonstrate smaller autonomic and cardiovascular reactions to stress, compared with men. The mechanism of this sex-dependent difference is unknown, although reduced baroreflex sensitivity may be involved. Recently, we identified a cortical network associated with autonomic cardiovascular responses to baroreceptor unloading in men. The current investigation examined whether differences in the neural activity patterns within this network were related to sex-related physiological responses to lower body negative pressure (LBNP, 5, 15, and 35 mmHg). Forebrain activity in healthy men and women (n = 8 each) was measured using functional magnetic resonance imaging with blood oxygen level-dependent (BOLD) contrast. Stroke volume (SV), heart rate (HR), and muscle sympathetic nerve activity (MSNA) were collected on a separate day. Men had larger decreases in SV than women (P < 0.01) during 35 mmHg LBNP only. At 35 mmHg LBNP, HR increased more in males then females (9 +/- 1 beats/min vs. 4 +/- 1 beats/min, P < 0.05). Compared with women, increases in total MSNA were similar at 15 mmHg LBNP but greater during 35 mmHg LBNP in men [1,067 +/- 123 vs. 658 +/- 103 arbitrary units (au), P < 0.05]. BOLD signal changes (P < 0.005, uncorrected) were identified within discrete forebrain regions associated with these sex-specific HR and MSNA responses. Men had larger increases in BOLD signal within the right insula and dorsal anterior cingulate cortex than women. Furthermore, men demonstrated greater BOLD signal reductions in the right amygdala, left insula, ventral anterior cingulate, and ventral medial prefrontal cortex vs. women. The greater changes in forebrain activity in men vs. women may have contributed to the elevated HR and sympathetic responses observed in men during 35 mmHg LBNP.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0363-6119
pubmed:author
pubmed:issnType
Print
pubmed:volume
292
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
R715-22
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:17272671-Adult, pubmed-meshheading:17272671-Autonomic Nervous System, pubmed-meshheading:17272671-Blood Pressure, pubmed-meshheading:17272671-Cardiovascular Physiological Phenomena, pubmed-meshheading:17272671-Cerebrovascular Circulation, pubmed-meshheading:17272671-Female, pubmed-meshheading:17272671-Heart Rate, pubmed-meshheading:17272671-Humans, pubmed-meshheading:17272671-Lower Body Negative Pressure, pubmed-meshheading:17272671-Magnetic Resonance Imaging, pubmed-meshheading:17272671-Male, pubmed-meshheading:17272671-Motor Activity, pubmed-meshheading:17272671-Muscle, Skeletal, pubmed-meshheading:17272671-Oxygen, pubmed-meshheading:17272671-Pressoreceptors, pubmed-meshheading:17272671-Prosencephalon, pubmed-meshheading:17272671-Regional Blood Flow, pubmed-meshheading:17272671-Sex Characteristics, pubmed-meshheading:17272671-Supine Position
pubmed:year
2007
pubmed:articleTitle
Forebrain neural patterns associated with sex differences in autonomic and cardiovascular function during baroreceptor unloading.
pubmed:affiliation
Neurovascular Research Laboratory, Faculty of Health Sciences and School of Kinesiology, The University of Western Ontario, London, Ontario, Canada.
pubmed:publicationType
Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't