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New Approach for Brain Stimulation
Vaschillo E.G., Vaschillo B., Buckman J.F., and Bates M.E.
Department of Kinesiology and Health, Rutgers University
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Respiration Volume
Heart Rate
Systolic Arterial Pressure
Pulse Transit Time (PTT)
Stroke Volume
HR Baroreflex Gain
Skin Conductance
The BOLD follows the HRV; but in the BOLD frequency
components, higher than 0.2 Hz, are filtered out. Respiratory
~0.28 Hz oscillation is present in HRV, but absent in BOLD.
Baseline task
INTRODUCTION
Heart rate variability (HRV) biofeedback is a simple, natural, and noninvasive method for brain stimulation. The method includes rhythmical, paced breathing at a
rate of about 6 breaths per minute (0.1 Hz). HRV biofeedback has been successfully applied for the treatment of a wide spectrum of diseases, including asthma, COPD,
IBS, fibromyalgia, depression, anxiety, PTSD, insomnia, and many others. It also has been employed to improve performance in athletes and human operators.
Such diverse applications for HRV biofeedback suggest a centrally-mediated mechanism of action.
The goal of this study was to show the involvement of the baroreflex in this mechanism. The baroreflex system (BRS) optimizes blood flow distribution. The
baroreflex is a closed loop control system that diminishes oscillation in the blood pressure (BP) by changing beat to beat intervals of the heart. It is a safety mechanism that
prevents negative effects (e.g., syncope, stroke) to acute BP changes. However, the 5 s delay between the shift in BP and its return to previous level creates a resonance
property in the baroreflex system at the frequency of 0.1 Hz. Paced 0.1 Hz breathing triggers resonance in the BRS that involves many cardiovascular functions. Resonance
effects on the body and brain are presented.
Paced breathing at a rate of about 6 breaths/min causes high-
amplitude oscillation in heart rate. HRV modulates blood flow
and blood pressure (BP) in the aorta and carotid arteries and
triggers resonance in the baroreflex. Baroreflex control of BP
causes large oscillations in HR, stroke volume, and vascular
tone through sympathetic and parasympathetic nerves.
HRV Biofeedback Affects the Cardiovascular System HRV Biofeedback Affects the
Brain
Baseline HRV biofeedback procedure
breathing
Breathing at a rate of 6 times/min
causes 0.1 Hz oscillation in heart rate. breathing breathing
0.1 Hz HR oscillation triggers
resonance in the baroreflex.
Resonance causes high-amplitude
oscillation in the CVS and deeply modulates
blood flow in aorta and carotid arteries. breathing
Blood flow oscillation in the CVS
spreads into brain circulation.
HR Is Ahead of Breathing
During Resonance.
Respiration triggers resonance
in the BRS. However, in each
oscillation period, HR begins to
grow before the inhale starts.
Inhalation pushes HR to
increase.
Fourier Spectra of BOLD in 9 Brain Regions (M ±
STD Errors) Averaged across 15 Participants
Peaks in the BOLD spectra in the examined brain regions indicate that the diameter of arteries in
ROIs changes rhythmically at a frequency of 0.1 Hz (5 s dilation, 5 s constriction). Transfer function
analysis revealed that 0.1 Hz oscillation in each ROI is delayed in relation to HRV for a specific time
(See table). The observed delays suggest that the 0.1 Hz BOLD wave spreads across the brain regions.
We suggest that oscillations in the BOLD signal are caused by simultaneous mechanical high-
amplitude blood flow oscillation in aorta and carotid arteries, and neural afferent firing from
baroreceptors which is believed to modulate inhibitory activity in the brain.
We hypothesize that 0.1 Hz breathing results in large fluctuations in vessel diameter and,
consequently, the level of oxygenation in each brain region. This is consistent with clinical evidence that
HRV biofeedback improves cognitive, emotional, and physical functioning.
Reaction of the CVS to 6 times/min breathing
Association between HRV and BOLD
in the cerebellum.
METHOD
fMRI data, ECG, and respiration were
simultaneously collected (baseline task and
6 times/min (6P) task) in 15 college students
(18-25 years of age).
Physiology data were recorded using an
MRI-compatible BIOPAC acquisition system.
BOLD data were obtained using a 3T
Siemens Trio head-only fMRI scanner
equipped with a standard Siemens head coil.
The 0.1 Hz oscillations in BOLD and HRV are synchronized
with a delay.
Paced breathing 6 times/min 6P task
RESULTS
CONCLUSION
Transfer Function Analysis