Cerebral and Peripheral Hemodynamics Across Wakefulness and NREM Sleep.

Wake/sleep-related changes in cerebral hemodynamic oscillations are well established, but similar changes in peripheral hemodynamics remain largely understudied. Moreover, how the relationship between cerebral and peripheral hemodynamics varies across sleep-wake states is not well understood, despite evidence that these oscillations in the low-frequency range are strongly coupled during wakefulness. In this study, we investigated the temporal and spectral characteristics of cerebral and peripheral hemodynamics, as well as their low-frequency coupling, across sleep and wake states.

Coupling of Low Frequency Hemodynamic Oscillations Between the Brain and Spinal Cord.

In Functional Magnetic Resonance Imaging (fMRI), the primary contrast is Blood Oxygen Level Dependent (BOLD) signal. Systemic Low Frequency Oscillations (sLFO) are BOLD signals between 0.01 and 0.

Amplitude fluctuations of cerebrovascular oscillations and CSF movement desynchronize during NREM3 sleep.

Fluctuations in cerebral blood volume (CBV) are a dominant mechanism aiding cerebrospinal fluid (CSF) movement in the brain during wakefulness and non-rapid eye movement (NREM) sleep. However, it is unclear if the amplitudes of CBV oscillations also change in proportion to the changes in amplitude of CSF movement across specific NREM sleep states. It is also not known if the coupling strength between them varies between NREM sleep states.

Using respiratory challenges to modulate CSF movement across different physiological pathways: An fMRI study.

With growing evidence signifying the impact of cerebrospinal fluid (CSF) flow in facilitating waste clearance from the brain and potential pathophysiological links to neurodegenerative disorders, it is of vital importance to develop effective methods to modulate CSF flow in the brain. Here, we attempt this by means of simple commonly used respiratory challenges-paced breathing and breath holding. Functional Magnetic Resonance Imaging scans of the brain and neck respectively were used to record the craniad and caudad CSF movements at the fourth ventricle from eight healthy volunteers during paced breathing and breath holding.

Brain network hypersensitivity underlies pain crises in sickle cell disease.

Sickle cell disease (SCD) is a genetic disorder causing painful and unpredictable Vaso-occlusive crises (VOCs) through blood vessel blockages. In this study, we propose explosive synchronization (ES) as a novel approach to comprehend the hypersensitivity and occurrence of VOCs in the SCD brain network. We hypothesized that the accumulated disruptions in the brain network induced by SCD might lead to strengthened ES and hypersensitivity.

Real-time Quantification of in vivo cerebrospinal fluid velocity using fMRI inflow effect.

estimation of cerebrospinal fluid (CSF) velocity is crucial for understanding the glymphatic system and its potential role in neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. Current cardiac or respiratory gated approaches, such as 4D flow MRI, cannot capture CSF movement in real time due to limited temporal resolution and in addition deteriorate in accuracy at low fluid velocities. Other techniques like real-time PC-MRI or time-spatial labeling inversion pulse are not limited by temporal averaging but have limited availability even in research settings.

Brain network hypersensitivity underlies pain crises in sickle cell disease.

Sickle cell disease (SCD) is a genetic disorder causing blood vessel blockages and painful Vaso-occlusive crises (VOCs). VOCs, characterized by severe pain due to blocked blood flow, are recurrent and unpredictable, posing challenges for preventive strategies. In this study we propose explosive synchronization (ES), a phenomenon characterized by abrupt brain network phase transitions, as a novel approach to address this challenge.

mHealth hyperspectral learning for instantaneous spatiospectral imaging of hemodynamics.

Hyperspectral imaging acquires data in both the spatial and frequency domains to offer abundant physical or biological information. However, conventional hyperspectral imaging has intrinsic limitations of bulky instruments, slow data acquisition rate, and spatiospectral trade-off. Here we introduce hyperspectral learning for snapshot hyperspectral imaging in which sampled hyperspectral data in a small subarea are incorporated into a learning algorithm to recover the hypercube.

Coupling between cerebrovascular oscillations and CSF flow fluctuations during wakefulness: An fMRI study.

It is commonly believed that cerebrospinal fluid (CSF) movement is facilitated by blood vessel wall movements (i.e., hemodynamic oscillations) in the brain.