scholarly journals Multimodal mapping of neural activity and cerebral blood flow reveals long-lasting neurovascular dissociations after small-scale strokes

2020 ◽  
Vol 6 (21) ◽  
pp. eaba1933 ◽  
Author(s):  
Fei He ◽  
Colin T. Sullender ◽  
Hanlin Zhu ◽  
Michael R. Williamson ◽  
Xue Li ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Neural Activity ◽  
Brain Regions ◽  
Small Scale ◽  
Spatially Resolved ◽  
Relative Value ◽  
Brain States ◽  
Neuroimaging Techniques

Neurovascular coupling, the close spatial and temporal relationship between neural activity and hemodynamics, is disrupted in pathological brain states. To understand the altered neurovascular relationship in brain disorders, longitudinal, simultaneous mapping of neural activity and hemodynamics is critical yet challenging to achieve. Here, we use a multimodal neural platform in a mouse model of stroke and realize long-term, spatially resolved tracking of intracortical neural activity and cerebral blood flow in the same brain regions. We observe a pronounced neurovascular dissociation that occurs immediately after small-scale strokes, becomes the most severe a few days after, lasts into chronic periods, and varies with the level of ischemia. Neuronal deficits extend spatiotemporally, whereas restoration of cerebral blood flow occurs sooner and reaches a higher relative value. Our findings reveal the neurovascular impact of ministrokes and inform the limitation of neuroimaging techniques that infer neural activity from hemodynamic responses.

scholarly journals Multimodal mapping of neural activity and cerebral blood flow reveals long-lasting neurovascular dissociations after small-scale strokes

2020 ◽  
Author(s):  
Fei He ◽  
Colin Sullender ◽  
Hanlin Zhu ◽  
Michael R. Williamson ◽  
Xue Li ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Neural Activity ◽  
Brain Regions ◽  
Small Scale ◽  
Spatially Resolved ◽  
Relative Value ◽  
Brain States ◽  
Neuroimaging Techniques

AbstractNeurovascular coupling, the close spatial and temporal relationship between neural activity and hemodynamics, is disrupted in pathological brain states. To understand the altered neurovascular relationship in brain disorders, longitudinal, simultaneous mapping of neural activity and hemodynamics is critical yet challenging to achieve. Here, we employ a multimodal neural platform in a mouse model of stroke and realize long-term, spatially-resolved tracking of intracortical neural activity and cerebral blood flow in the same brain regions. We observe a pronounced neurovascular dissociation that occurs immediately after small-scale strokes, becomes the most severe a few days after, lasts into chronic periods, and varies with the level of ischemia. Neuronal deficits extend spatiotemporally whereas restoration of cerebral blood flow occurs sooner and reaches a higher relative value. Our findings reveal the neurovascular impact of mini-strokes and inform the limitation of neuroimaging techniques that infer neural activity from hemodynamic responses.

scholarly journals Cerebral Blood Flow in Posterior Cortical Nodes of the Default Mode Network Decreases with Task Engagement but Remains Higher than in Most Brain Regions

2010 ◽  
Vol 21 (1) ◽  
pp. 233-244 ◽  
Author(s):  
A. Pfefferbaum ◽  
S. Chanraud ◽  
A.-L. Pitel ◽  
E. Muller-Oehring ◽  
A. Shankaranarayanan ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Default Mode Network ◽  
Brain Regions ◽  
Task Engagement ◽  
Default Mode

scholarly journals Fundamental Dynamical Modes Underlying Human Brain Synchronization

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Catalina Alvarado-Rojas ◽  
Michel Le Van Quyen
Keyword(s):  
Large Scale ◽  
Brain Regions ◽  
Electrode Placement ◽  
High Dimensional ◽  
Sleep Cycle ◽  
Epileptic Patients ◽  
Brain States ◽  
Intracranial Recordings ◽  
Characteristic Dynamic

Little is known about the long-term dynamics of widely interacting cortical and subcortical networks during the wake-sleep cycle. Using large-scale intracranial recordings of epileptic patients during seizure-free periods, we investigated local- and long-range synchronization between multiple brain regions over several days. For such high-dimensional data, summary information is required for understanding and modelling the underlying dynamics. Here, we suggest that a compact yet useful representation is given by a state space based on the first principal components. Using this representation, we report, with a remarkable similarity across the patients with different locations of electrode placement, that the seemingly complex patterns of brain synchrony during the wake-sleep cycle can be represented by a small number of characteristic dynamic modes. In this space, transitions between behavioral states occur through specific trajectories from one mode to another. These findings suggest that, at a coarse level of temporal resolution, the different brain states are correlated with several dominant synchrony patterns which are successively activated across wake-sleep states.

Abstract 196: Sanguinate (PEGylated-carboxyhemoglobin-bovine) Improves Cerebral Blood Flow and Oxygen Extraction to Vulnerable Brain Regions in Patients at Risk for Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Rajat Dhar ◽  
Hemant Misra ◽  
Michael Diringer
Keyword(s):  
At Risk ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Delayed Cerebral Ischemia ◽  
Brain Regions ◽  
Oxygen Extraction ◽  
Patients At Risk ◽  
Higher Doses

Introduction: Sanguinate is a dual-action oxygen transfer and carbon monoxide-releasing agent with efficacy in animal models of focal brain ischemia and established safety in health volunteers. We performed a dose-escalation study in subarachnoid hemorrhage (SAH) patients at risk for delayed cerebral ischemia (DCI) to evaluate tolerability and explore efficacy in improving cerebral blood flow (CBF) and flow-metabolism balance to vulnerable brain regions. Methods: 12 subjects were studied over three dose tiers: 160mg/kg, 240 mg/kg, and 320 mg/kg, with close safety evaluation prior to proceeding to higher doses. After baseline 15 O-PET measurement of global and regional CBF and oxygen extraction fraction (OEF), Sanguinate was infused over two hours; PET was repeated immediately after and again at 24-hours. Vulnerable brain regions were defined as those with baseline OEF ≥ 0.5. Results: Sanguinate infusion resulted in a significant but transient rise in mean arterial pressure (115±15 to 127±13 mm Hg) that was not dose-dependent. No adverse physiologic or clinical effects were observed with infusion at any dose. Global CBF did not rise significantly after Sanguinate (42.6±7 to 45.9±9 ml/100g/min, p=0.18). However, in the 28% of regions classified as vulnerable, Sanguinate resulted in a significant rise in CBF (42.2±11 to 51.2±18) and reduction in OEF (0.6±0.1 to 0.5±0.11, both p<0.001). The increase in regional CBF was only seen with the two higher doses but OEF improved in all tiers. However, response was attenuated at 24-hours. Conclusions: We safely administered a novel oxygen transport and vasodilating agent to a cohort of patients with SAH. Sanguinate infusion appeared to improve CBF and flow-metabolism balance in vulnerable brain regions and warrants further study in those at-risk for DCI. Higher or repeat dosing may be required for sustained efficacy.

Effects of temperature and anoxia on regional cerebral blood flow in turtles

1992 ◽  
Vol 262 (3) ◽  
pp. R538-R541
Author(s):  
P. E. Bickler
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Brain Regions ◽  
Platinum Electrodes ◽  
Regional Cerebral Blood ◽  
Blood Flows ◽  
Effects Of Temperature ◽  
Kinetics Of ◽  
Hydrogen Clearance

Regional cerebral blood flow (CBF) was measured in isoflurane-anesthetized turtles (Pseudemys scripta) by the hydrogen clearance method. Teflon-coated platinum electrodes (25 microns) were implanted in the olfactory bulbs, midcerebral cortex and cerebellum in eight adult turtles. The electrodes were voltage clamped at +0.30 V relative to a Ag-AgCl electrode implanted in the dorsal neck muscles. Washout kinetics of H2 gas administered via controlled ventilation was used to calculate local blood flow for electrodes exhibiting monoexponential washout kinetics of hydrogen (92 of 104 determinations). Data were obtained in animals with body temperatures of 15, 25, and 35 degrees C under normocapnic conditions during ventilation with 21% O2 and during ventilation with 100% N2. During normoxia, mean blood flows were 1.9 +/- 0.8, 5.0 +/- 1.9, and 6.1 +/- 1.3 (+/- SD) ml.100 g-1.min-1 at 15, 25, and 35 degrees C, respectively. There were no differences between CBF values in the different brain regions. During 1-3 h of anoxia, CBF was 3.0 +/- 2.1, 7.0 +/- 3.7, and 6.6 +/- 2.9 ml.100 g-1.min-1 at 15, 25, and 35 degrees C, respectively (normoxia-anoxia difference not statistically different). Hypercarbia (ventilation with 10-20% CO2 in air or N2), or the transition from anoxia to normoxia, increased CBF up to 80% at each of these temperatures. Maintenance of CBF during anoxia likely contributes to the anoxia tolerance of the turtle brain.

Cerebral blood flow and energy metabolism during stress

1990 ◽  
Vol 259 (2) ◽  
pp. H269-H280 ◽  
Author(s):  
R. M. Bryan
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Energy Metabolism ◽  
Adrenergic Receptor ◽  
Conditioned Fear ◽  
Brain Regions ◽  
Stressful Events ◽  
Ethanol Withdrawal ◽  
Adrenergic Mechanism ◽  
The Brain

Many, but not all, stressful events are accompanied by increases in cerebral blood flow and/or energy metabolism. The stressful events include pharmacological paralysis, footshock, conditioned fear, hypotension, hypoglycemia, hypoxia, noise, and ethanol withdrawal. These increases are significant because 1) all brain regions are often affected, i.e., certain stressful events have global effects on cerebral blood flow and energy metabolism; and 2) various stressful events appear to have a common adrenergic mechanism for increasing cerebral blood flow and energy metabolism. The adrenergic mechanism involves beta-adrenergic receptor stimulation by either epinephrine secreted from the adrenal medulla or possibly norepinephrine endogenous to the brain. While adrenergic mechanisms are not the only mechanism controlling flow and metabolism for a given stressful condition, they do appear to be common to many situations. At least part of the increase in cerebral blood flow and energy metabolism during many conditions appears to be the result of the stress response and not directly a result of the condition itself.

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