Breath hold effect on cardiovascular brain pulsations – A multimodal magnetic resonance encephalography study

Abstract

Ultra-fast functional magnetic resonance encephalography (MREG) enables separate assessment of cardiovascular, respiratory, and vasomotor waves from brain pulsations without temporal aliasing. We examined effects of breath hold- (BH) related changes on cardiovascular brain pulsations using MREG to study the physiological nature of cerebrovascular reactivity. We used alternating 32 s BH and 88 s resting normoventilation (NV) to change brain pulsations during MREG combined with simultaneously measured respiration, continuous non-invasive blood pressure, and cortical near-infrared spectroscopy (NIRS) in healthy volunteers. Changes in classical resting-state network BOLD-like signal and cortical blood oxygenation were reproduced based on MREG and NIRS signals. Cardiovascular pulsation amplitudes of MREG signal from anterior cerebral artery, oxygenated hemoglobin concentration in frontal cortex, and blood pressure decreased after BH. MREG cardiovascular pulse amplitudes in cortical areas and sagittal sinus increased, while cerebrospinal fluid and white matter remained unchanged. Respiratory centers in the brainstem - hypothalamus - thalamus - amygdala network showed strongest increases in cardiovascular pulsation amplitude. The spatial propagation of averaged cardiovascular impulses altered as a function of successive BH runs. The spread of cardiovascular pulse cycles exhibited a decreasing spatial similarity over time. MREG portrayed spatiotemporally accurate respiratory network activity and cardiovascular pulsation dynamics related to BH challenges at an unpreceded high temporal resolution.

Respiratory-related brain pulsations are increased in epilepsy—a two-centre functional MRI study

“…In addition, the physiological brain pulsations may induce local elastic brain fluctuation/motion that can be addressed with fast scanning more thoroughly in the future. Therefore, the interaction between the cardiac and respiratory pulsations in brain parenchyma is gathering increasing interest in fMRI ( Chang et al , 2013 ; Raitamaa et al , 2019 ).…”

“…In addition, one cubic region-of-interest from the pneumotaxic and apneustic centres in the brainstem was chosen for signal calculation ( Raitamaa et al ., 2019 ). Upper and lower smooth curves, i.e.…”

“…In addition to the haemodynamic BOLD effect to neuronal activity, fast fMRI sequences enable the detection of physiological oscillations as propagating cardiac and respiratory pulsations within their respective frequency sub-bands ( Posse et al , 2013 ; Kiviniemi et al , 2016 ; Raitamaa et al ., 2019 ; Aslan et al , 2019 ; Rajna et al , 2019 ). Previously, these physiological pulsations have been regarded as artefacts with little relevance to the underlying pathology.…”

Dynamic lag analysis reveals atypical brain information flow in autism spectrum disorder

“…In other words, the lag structure enables one to follow the BOLD signal propagation between networks based on the temporal order of succeeding activation peaks detected in the resting‐state networks (RSNs). With the novel ultrafast imaging techniques without cardiorespiratory aliasing, one can estimate resting‐state metrics and lag structure more precisely [Huotari et al, ; Raatikainen et al, ; Raitamaa et al, ; Rajna et al, ]. No previous investigations of autism have concentrated on dynamic lag pattern variations in individuals with the disorder compared with NT individuals.…”

Sleep-specific changes in physiological brain pulsations

“…Although it is known that the physiological pulsation can affect the BOLD signal, this interaction has not been widely studied due to technical limitations of conventional fMRI (Huotari et al, 2019;Kiviniemi et al, 2016). The acquisition of ultrafast MREGBOLD data enables robust separation of the cardiac and respiratory pulsations due to absence of signal aliasing (Huotari et al, 2019;Kiviniemi et al, 2016;Raitamaa et al, 2018) over the VLF frequencies.…”