Synchronous Multiscale Neuroimaging Environment for Critically Sampled Physiological Analysis of Brain Function: Hepta-Scan Concept

Korhonen, Vesa; Hiltunen, Tuija; Myllylä, Teemu; Wang, Xindi; Kantola, Jussi; Nikkinen, Juha; Zang, Yu‐Feng; LeVan, Pierre; Kiviniemi, Vesa

doi:10.1089/brain.2014.0258

Cited by 45 publications

(73 citation statements)

References 87 publications

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“…Multimodal imaging was carried out using our Hepta‐scan concept, in which fast fMRI data was imaged simultaneously and synchronously with EEG, noninvasive blood pressure (NIBP), and near‐infrared spectroscopy (NIRS), and anesthesia monitor data (Korhonen et al., 2014). We also utilized the MRI scanner′s own respiratory bellows and peripheral capillary oxygen saturation meters.…”

Section: Methodsmentioning

confidence: 99%

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Altered physiological brain variation in drug‐resistant epilepsy

et al. 2018

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IntroductionFunctional magnetic resonance imaging (fMRI) combined with simultaneous electroencephalography (EEG‐fMRI) has become a major tool in mapping epilepsy sources. In the absence of detectable epileptiform activity, the resting state fMRI may still detect changes in the blood oxygen level‐dependent signal, suggesting intrinsic alterations in the underlying brain physiology.MethodsIn this study, we used coefficient of variation (CV) of critically sampled 10 Hz ultra‐fast fMRI (magnetoencephalography, MREG) signal to compare physiological variance between healthy controls (n = 10) and patients (n = 10) with drug‐resistant epilepsy (DRE).ResultsWe showed highly significant voxel‐level (p < 0.01, TFCE‐corrected) increase in the physiological variance in DRE patients. At individual level, the elevations range over three standard deviations (σ) above the control mean (μ) CVMREG values solely in DRE patients, enabling patient‐specific mapping of elevated physiological variance. The most apparent differences in group‐level analysis are found on white matter, brainstem, and cerebellum. Respiratory (0.12–0.4 Hz) and very‐low‐frequency (VLF = 0.009–0.1 Hz) signal variances were most affected.ConclusionsThe CVMREG increase was not explained by head motion or physiological cardiorespiratory activity, that is, it seems to be linked to intrinsic physiological pulsations. We suggest that intrinsic brain pulsations play a role in DRE and that critically sampled fMRI may provide a powerful tool for their identification.

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Section: Methodsmentioning

confidence: 99%

“…Gradient and ballistocardiographic artifact correction was carried out with the average artifact subtraction method (Allen, Josephs, & Turner, 2000; Allen, Polizzi, Krakow, Fish, & Lemieux, 1998) as in our previous studies (Hiltunen et al., 2014; Korhonen et al., 2014). …”

Section: Methodsmentioning

confidence: 99%

Altered physiological brain variation in drug‐resistant epilepsy

et al. 2018

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“…Other physiological data were obtained using a MRIcompatible synchronous multimodal neuroimaging system fitted to the 3T Skyra imaging room. 23 …”

Section: Magnetic Resonance Imaging Scannermentioning

confidence: 99%

“…23 MREG imaging-induced gradient and ballistocardiographic artefacts were removed using Brain Analyser software. This was followed by removal of linear and quadratic trends.…”

Section: Cardiovascular and Respiratory Signal Processingmentioning

confidence: 99%

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Ultra-fast magnetic resonance encephalography of physiological brain activity – Glymphatic pulsation mechanisms?

Kiviniemi

Wang

Korhonen

et al. 2015

J Cereb Blood Flow Metab

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The theory on the glymphatic convection mechanism of cerebrospinal fluid holds that cardiac pulsations in part pump cerebrospinal fluid from the peri-arterial spaces through the extracellular tissue into the peri-venous spaces facilitated by aquaporin water channels. Since cardiac pulses cannot be the sole mechanism of glymphatic propulsion, we searched for additional cerebrospinal fluid pulsations in the human brain with ultra-fast magnetic resonance encephalography. We detected three types of physiological mechanisms affecting cerebral cerebrospinal fluid pulsations: cardiac, respiratory, and very low frequency pulsations. The cardiac pulsations induce a negative magnetic resonance encephalography signal change in peri-arterial regions that extends centrifugally and covers the brain in &1 Hz cycles. The respiratory &0.3 Hz pulsations are centripetal periodical pulses that occur dominantly in peri-venous areas. The third type of pulsation was very low frequency (VLF 0.001-0.023 Hz) and low frequency (LF 0.023-0.73 Hz) waves that both propagate with unique spatiotemporal patterns. Our findings using critically sampled magnetic resonance encephalography open a new view into cerebral fluid dynamics. Since glymphatic system failure may precede protein accumulations in diseases such as Alzheimer's dementia, this methodological advance offers a novel approach to image brain fluid dynamics that potentially can enable early detection and intervention in neurodegenerative diseases.

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Spectral analysis of physiological brain pulsations affecting the BOLD signal

Raitamaa

Huotari

Korhonen

et al. 2021

Human Brain Mapping

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Physiological pulsations have been shown to affect the global blood oxygen level dependent (BOLD) signal in human brain. While these pulsations have previously been regarded as noise, recent studies show their potential as biomarkers of brain pathology. We used the extended 5 Hz spectral range of magnetic resonance encephalography (MREG) data to investigate spatial and frequency distributions of physiological BOLD signal sources. Amplitude spectra of the global image signals revealed cardiorespiratory envelope modulation (CREM) peaks, in addition to the previously known very low frequency (VLF) and cardiorespiratory pulsations. We then proceeded to extend the amplitude of low frequency fluctuations (ALFF) method to each of these pulsations. The respiratory pulsations were spatially dominating over most brain structures. The VLF pulsations overcame the respiratory pulsations in frontal and parietal gray matter, whereas cardiac and CREM pulsations had this effect in central cerebrospinal fluid (CSF) spaces and major blood vessels. A quasi‐periodic pattern (QPP) analysis showed that the CREM pulsations propagated as waves, with a spatiotemporal pattern differing from that of respiratory pulsations, indicating them to be distinct intracranial physiological phenomenon. In conclusion, the respiration has a dominant effect on the global BOLD signal and directly modulates cardiovascular brain pulsations.

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Synchronous Multiscale Neuroimaging Environment for Critically Sampled Physiological Analysis of Brain Function: Hepta-Scan Concept

Cited by 45 publications

References 87 publications

Altered physiological brain variation in drug‐resistant epilepsy

Altered physiological brain variation in drug‐resistant epilepsy

Ultra-fast magnetic resonance encephalography of physiological brain activity – Glymphatic pulsation mechanisms?

Spectral analysis of physiological brain pulsations affecting the BOLD signal

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