Autonomic Neural Control of Cardiac Function

Levy, Matthew N.; Martin, Paul J.

doi:10.1007/978-1-4613-0873-7_17

Cited by 68 publications

(76 citation statements)

References 52 publications

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“…Under physiological conditions and without a significant change in respiratory signal power within the HF power band (confirmed in our data), HF power of the HR signal is an expedient marker of parasympathetic modulation (Malik et al 1996). The SA node responds very quickly to vagal (~150msec latency, steady state at 1-2sec), in contrast to sympathetic (~1-2sec latency, steady state at 30-60sec), influence (Spear et al 1979;Levy 1997). Hence, continuous HF power is an excellent metric to use as a regressor within the fMRI GLM framework, given the temporal resolution of fMRI.…”

Section: Discussionsupporting

confidence: 81%

Brain correlates of autonomic modulation: Combining heart rate variability with fMRI

Napadow¹,

Dhond²,

Conti³

et al. 2008

NeuroImage

302

229

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The central autonomic network (CAN) has been described in animal models but has been difficult to elucidate in humans. Potential confounds include physiological noise artifacts affecting brainstem neuroimaging data, and difficulty in deriving non-invasive continuous assessments of autonomic modulation. We have developed and implemented a new method which relates cardiac-gated fMRI timeseries with continuous-time heart rate variability (HRV) to estimate central autonomic processing. As many autonomic structures of interest are in brain regions strongly affected by cardiogenic pulsatility, we chose to cardiac-gate our fMRI acquisition to increase sensitivity. Cardiac-gating introduces T1-variability, which was corrected by transforming fMRI data to a fixed TR using a previously published method (Guimaraes et al. 1998). The electrocardiogram was analyzed with a novel point process adaptive-filter algorithm for computation of the high-frequency (HF) index, reflecting the time-varying dynamics of efferent cardiovagal modulation. Central command of cardiovagal outflow was inferred by using the HF timeseries resampled at as a regressor to the fMRI data. A grip task was used to perturb the autonomic nervous system. Our combined HRV-fMRI approach demonstrated HF correlation with fMRI activity in the hypothalamus, cerebellum, parabrachial nucleus/locus ceruleus, periaqueductal gray, amygdala, hippocampus, thalamus, and dorsomedial/dorsolateral prefrontal, posterior insular, and middle temporal cortices. While some regions consistent with central cardiovagal control in animal models gave corroborative evidence for our methodology, other mostly higher cortical or limbic-related brain regions may be unique to humans. Our approach should be optimized and applied to study the human brain correlates of autonomic modulation for various stimuli in both physiological and pathological states.

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Section: Discussionsupporting

confidence: 81%

Brain correlates of autonomic modulation: Combining heart rate variability with fMRI

Napadow¹,

Dhond²,

Conti³

et al. 2008

NeuroImage

302

229

View full text Add to dashboard Cite

show abstract

“…are left unaccounted. Although previous studies suggest that the interactive effects would probably not be substantial in the physiological range of our manipulations, they are not zero~Berntson et al, 1994;Levy, 1997;Uijtdehaage & Thayer, 2000!. Second, changes in heart rate caused by an independent second vagal-cardiac pathway that has its origin in the Dorsal Motor Nucleus~DMNX!…”

Section: Tonic Vagal Modulation Of Heart Ratementioning

confidence: 83%

Contribution of tonic vagal modulation of heart rate, central respiratory drive, respiratory depth, and respiratory frequency to respiratory sinus arrhythmia during mental stress and physical exercise

Rietveld

Geus

2002

Psychophysiol.

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This study tested various sources of changes in respiratory sinus arrhythmia~RSA!. Twenty-two healthy participants participated in three experimental conditions~mental stress, relaxation, and mild physical exercise! that each consisted of three breathing parts~normal breathing, breathing compressed room air, and breathing compressed 5% CO 2 -enriched air!. Independent contributions to changes in RSA were found for changes in tonic vagal modulation of heart rate, central respiratory drive~i.e., PaCO 2 !, respiratory depth, and respiratory frequency. The relative contributions to changes in RSA differed for mental stress and physical exercise. It is concluded that uncorrected RSA will suffice to index within-subject changes in tonic vagal modulation of heart rate in most situations. However, if the central respiratory drive is expected to change, RSA should ideally be corrected for changes in PaCO 2 , respiratory depth, and respiratory frequency.

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“…Control of heart rate generally depends on complex interactions between sympathetic and vagal cardiac drive. 19 The slower heart rate in LQTS may be explained by high vagal or low cardiac sympathetic activity, or both. Furthermore, we cannot completely exclude the possibility of an abnormality of sinus node automaticity.…”

Section: Discussionmentioning

confidence: 99%

Sympathetic Nerve Activity in the Congenital Long-QT Syndrome

et al. 2003

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Background-Patients with congenital long-QT syndrome (LQTS) are susceptible to life-threatening arrhythmias. The sympathetic nervous system may have an important triggering role for cardiovascular events in LQTS. We therefore examined measurements of sympathetic neural traffic in patients with LQTS and matched control subjects. Methods and Results-Twelve patients with congenital LQTS and 12 healthy volunteers matched for age, sex, and body mass index were studied. Heart rate, respiration, blood pressure, and sympathetic nerve activity to the skeletal muscle blood vessels (muscle sympathetic nerve activity) and to the skin (skin sympathetic nerve activity) were monitored and recorded continuously. Resting heart rate (P‫,)30.0؍‬ muscle sympathetic nerve activity burst rate (Pϭ0.008), and burst incidence (Pϭ0.02) were lower in patients with LQTS than in control subjects. However, skin sympathetic nerve activity was very similar in patients with LQTS and control subjects. Spectral analysis of RR variability showed a decreased low-frequency component, an increased high-frequency component, and a decrease in the ratio of the low-frequency component to the high-frequency component in patients with LQTS (Pϭ0.01). Conclusions-LQTS is associated with a selective reduction in sympathetic drive to muscle blood vessels and perhaps also to the heart.

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Autonomic Neural Control of Cardiac Function

Cited by 68 publications

References 52 publications

Brain correlates of autonomic modulation: Combining heart rate variability with fMRI

Brain correlates of autonomic modulation: Combining heart rate variability with fMRI

Contribution of tonic vagal modulation of heart rate, central respiratory drive, respiratory depth, and respiratory frequency to respiratory sinus arrhythmia during mental stress and physical exercise

Sympathetic Nerve Activity in the Congenital Long-QT Syndrome

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