Pacemaker Neurons and Neuronal Networks in Health and Disease

Peña‐Ortega, Fernando

doi:10.5772/50264

Cited by 1 publication

(1 citation statement)

References 88 publications

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“…The availability of various BOLD signals in a close proximity of a few millimeters in pons/brain stem suggests that the neural oscillatory source is not focused and not stable in a specific localization but has its origin very likely in a dispersive neural network ( Ramirez et al, 2004 ) in the brain stem. Neural network dynamics are not fixed but depend on the state of the network or on the action of neuromodulators ( Peña-Ortega, 2012 ), which is in accordance with our observations. The SSMTD of 2.2 ± 0.2 s documents that the time delay between RRI and almost undisturbed neural BOLD oscillations in the pons/brain stem is relatively rare.…”

Section: Discussionsupporting

confidence: 89%

Verification of a Central Pacemaker in Brain Stem by Phase-Coupling Analysis Between HR Interval- and BOLD-Oscillations in the 0.10–0.15 Hz Frequency Band

et al. 2020

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The origin of slow intrinsic oscillations in resting states of functional magnetic resonance imaging (fMRI) signals is still a matter of debate. The present study aims to test the hypothesis that slow blood oxygenation level-dependent (BOLD) oscillations with frequency components greater than 0.10 Hz result from a central neural pacemaker located in the brain stem. We predict that a central oscillator modulates cardiac beatto-beat interval (RRI) fluctuations rapidly, with only a short neural lag around 0.3 s. Spontaneous BOLD fluctuations in the brain stem, however, are considerably delayed due to the hemodynamic response time of about ∼2-3 s. In order to test these predictions, we analyzed the time delay between slow RRI oscillations from thorax and BOLD oscillations in the brain stem by calculating the phase locking value (PLV). Our findings show a significant time delay of 2.2 ± 0.2 s between RRI and BOLD signals in 12 out of 23 (50%) participants in axial slices of the pons/brain stem. Adding the neural lag of 0.3 s to the observed lag of 2.2 s we obtain 2.5 s, which is the time between neural activity increase and BOLD increase, termed neuro-BOLD coupling. Note, this time window for neuro-BOLD coupling in awake humans is surprisingly of similar size as in awake head-fixed adult mice (Mateo et al., 2017).

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Section: Discussionsupporting

confidence: 89%