scholarly journals Neurovascular Coupling and Epilepsy: Hemodynamic Markers for Localizing and Predicting Seizure Onset

2007 ◽  
Vol 7 (4) ◽  
pp. 91-94 ◽  
Author(s):  
Theodore H. Schwartz
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Neurovascular Coupling ◽  
Epileptic Activity ◽  
Tissue Hypoxia ◽  
Epileptic Focus ◽  
Seizure Onset

Hemodynamic surrogates of epileptic activity are being used to map epileptic foci with PET, SPECT, and fMRI. However, there are few studies of neurovascular coupling in epilepsy. Recent data indicate that cerebral blood flow, although focally increased at the onset of a seizure, may be temporarily inadequate to meet the metabolic demands of both interictal and ictal epileptic events. Transient focal tissue hypoxia and hyperperfusion may be excellent markers for the epileptic focus and may even precede the onset of the ictal event.

scholarly journals Cerebral blood flow and temporal lobe epileptogenicity

1996 ◽  
Vol 1 (5) ◽  
pp. E5 ◽  
Author(s):  
Martin E. Weinand ◽  
L. Philip Carter ◽  
Waleed F. El-Saadany ◽  
Panayiotis J. Sioutos ◽  
David M. Labiner ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Temporal Lobe ◽  
Temporal Cortex ◽  
Epileptic Focus ◽  
Seizure Onset ◽  
Temporal Lobes ◽  
Clinical Seizure ◽  
The Difference ◽  
Cortical Perfusion

Long-term surface cerebral blood flow (CBF) monitoring was performed to test the hypothesis that temporal lobe epileptogenicity is a function of epileptic cortical perfusion. Forty-three bitemporal 2-hour periictal CBF studies were performed in 13 patients. Homotopic regions of temporal cortex maintained interictal epileptic cortical hypoperfusion and nonepileptic normal cortical CBF. At 10 minutes preictus, a statistically significant, sustained increase in CBF was detected on the epileptic temporal lobe. Two minutes preictus, there was approximation of CBF in the epileptic and nonepileptic temporal lobes. Thereafter, electrocorticographic (ECoG) and clinical seizure onset occurred. The linear relationship between CBF in the two hemispheres (epileptic and nonepileptic) was the inverse of normal (y = -0.347x + 62.767, r = 0.470, df = 95, p < 0.05). The data indicated a direct linear correlation between epileptic cortical CBF and seizure interval (frequency-1), a clinical measure of epileptogenicity (r = 0.610, df = 49, p < 0.05). Epileptogenicity was also found to be a logarithmic function of the difference between nonepileptic and epileptic cortical perfusion (r = 0.564, df = 58, t = 5.20, p < 0.05). The results showed that progressive hypoperfusion of the epileptic focus correlated with a decreased seizure interval (increased epileptogenicity). Increased perfusion of the epileptic focus correlated with an increased seizure interval (decreased epileptogenicity). The fact that CBF alterations precede ECoG seizure activity suggests that vasomotor changes may produce electrical and clinical seizure onset.

Cerebral blood flow and temporal lobe epileptogenicity

1997 ◽  
Vol 86 (2) ◽  
pp. 226-232 ◽  
Author(s):  
Martin E. Weinand ◽  
L. Philip Carter ◽  
Waleed F. El-Saadany ◽  
Panayiotis J. Sioutos ◽  
David M. Labiner ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Temporal Lobe ◽  
Temporal Cortex ◽  
Epileptic Focus ◽  
Seizure Onset ◽  
Content Type ◽  
Clinical Seizure ◽  
The Difference ◽  
Cortical Perfusion

✓ Long-term surface cerebral blood flow (CBF) monitoring was performed to test the hypothesis that temporal lobe epileptogenicity is a function of epileptic cortical perfusion. Forty-three bitemporal 2-hour periictal CBF studies were performed in 13 patients. Homotopic regions of temporal cortex maintained interictal epileptic cortical hypoperfusion and nonepileptic normal cortical CBF. At 10 minutes preictus, a statistically significant, sustained increase in CBF was detected on the epileptic temporal lobe. Two minutes preictus, there was approximation of CBF in the epileptic and nonepileptic temporal lobes. Thereafter, electrocorticographic (ECoG) and clinical seizure onset occurred. The linear relationship between CBF in the two hemispheres (epileptic and nonepileptic) was the inverse of normal (y = −0.347x + 62.767, r = 0.470, df = 95, p < 0.05). The data indicated a direct linear correlation between epileptic cortical CBF and seizure interval (frequency−1), a clinical measure of epileptogenicity (r = 0.610, df = 49, p < 0.05). Epileptogenicity was also found to be a logarithmic function of the difference between nonepileptic and epileptic cortical perfusion (r = 0.564, df = 58, t = 5.20, p < 0.05). The results showed that progressive hypoperfusion of the epileptic focus correlated with a decreased seizure interval (increased epileptogenicity). Increased perfusion of the epileptic focus correlated with an increased seizure interval (decreased epileptogenicity). The fact that CBF alterations precede ECoG seizure activity suggests that vasomotor changes may produce electrical and clinical seizure onset.

scholarly journals Functional and anatomical evidence of cerebral tissue hypoxia in young sickle cell anemia mice

2016 ◽  
Vol 37 (3) ◽  
pp. 994-1005 ◽  
Author(s):  
Lindsay S Cahill ◽  
Lisa M Gazdzinski ◽  
Albert KY Tsui ◽  
Yu-Qing Zhou ◽  
Sharon Portnoy ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Tissue ◽  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Cell Model ◽  
Ex Vivo ◽  
Tissue Hypoxia ◽  
Brain Physiology ◽  
The Brain

Cerebral ischemia is a significant source of morbidity in children with sickle cell anemia; however, the mechanism of injury is poorly understood. Increased cerebral blood flow and low hemoglobin levels in children with sickle cell anemia are associated with increased stroke risk, suggesting that anemia-induced tissue hypoxia may be an important factor contributing to subsequent morbidity. To better understand the pathophysiology of brain injury, brain physiology and morphology were characterized in a transgenic mouse model, the Townes sickle cell model. Relative to age-matched controls, sickle cell anemia mice demonstrated: (1) decreased brain tissue pO2 and increased expression of hypoxia signaling protein in the perivascular regions of the cerebral cortex; (2) elevated basal cerebral blood flow , consistent with adaptation to anemia-induced tissue hypoxia; (3) significant reduction in cerebrovascular blood flow reactivity to a hypercapnic challenge; (4) increased diameter of the carotid artery; and (5) significant volume changes in white and gray matter regions in the brain, as assessed by ex vivo magnetic resonance imaging. Collectively, these findings support the hypothesis that brain tissue hypoxia contributes to adaptive physiological and anatomic changes in Townes sickle cell mice. These findings may help define the pathophysiology for stroke in children with sickle cell anemia.

Neurovascular Coupling in Seizures

Neuroglia ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 36-47
Author(s):  
G. Campbell Teskey ◽  
Cam Ha T. Tran
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Functional Imaging ◽  
Neurological Disorders ◽  
Seizure Activity ◽  
Current Knowledge ◽  
Imaging Techniques ◽  
Neurovascular Coupling ◽  
Functional Brain Imaging ◽  
Blood Flow Control

Neurovascular coupling is a key control mechanism in cerebral blood flow (CBF) regulation. Importantly, this process was demonstrated to be affected in several neurological disorders, including epilepsy. Neurovascular coupling (NVC) is the basis for functional brain imaging, such as PET, SPECT, fMRI, and fNIRS, to assess and map neuronal activity, thus understanding NVC is critical to properly interpret functional imaging signals. However, hemodynamics, as assessed by these functional imaging techniques, continue to be used as a surrogate to map seizure activity; studies of NVC and cerebral blood flow control during and following seizures are rare. Recent studies have provided conflicting results, with some studies showing focal increases in CBF at the onset of a seizure while others show decreases. In this brief review article, we provide an overview of the current knowledge state of neurovascular coupling and discuss seizure-related alterations in neurovascular coupling and CBF control.

scholarly journals Effect of healthy aging on cerebral blood flow, CO2 reactivity, and neurovascular coupling during exercise

2018 ◽  
Vol 125 (6) ◽  
pp. 1917-1930 ◽  
Author(s):  
Daniela Nowak-Flück ◽  
Philip N. Ainslie ◽  
Anthony R. Bain ◽  
Amar Ahmed ◽  
Kevin W. Wildfong ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Healthy Aging ◽  
Internal Carotid ◽  
Neurovascular Coupling ◽  
Dynamic Exercise ◽  
Older Individuals

We sought to make the first comparisons of duplex Doppler ultrasonography-derived measures of cerebral blood flow during exercise in young and older individuals and to assess whether healthy aging influences the effect of exercise on neurovascular coupling (NVC) and cerebral vascular reactivity to changes in carbon dioxide (CVRco2). In 10 healthy young (23 ± 2 yr; mean ± SD) and 9 healthy older (66 ± 3 yr) individuals, internal carotid artery (ICA) and vertebral artery (VA) blood flows were concurrently measured, along with middle and posterior cerebral artery mean blood velocity (MCAvmean and PCAvmean). Measures were made at rest and during leg cycling (75 W and 35% maximum aerobic workload). ICA and VA blood flow during dynamic exercise, undertaken at matched absolute (ICA: young 336 ± 95, older 352 ± 155; VA: young 95 ± 43, older 100 ± 30 ml/min) and relative (ICA: young 355 ± 125, older 323 ± 153; VA: young 115 ± 48, older 110 ± 32 ml/min) intensities, were not different between groups ( P > 0.670). The PCAvmean responses to visual stimulation (NVC) were blunted in older versus younger group at rest (16 ± 6% vs. 23 ± 7%, P < 0.026) and exercise; however, these responses were not changed from rest to exercise in either group. The ICA and VA CVRco2 were comparable in both groups and unaltered during exercise. Collectively, our findings suggest that 1) ICA and VA blood flow responses to dynamic exercise are similar in healthy young and older individuals, 2) NVC is blunted in healthy older individuals at rest and exercise but is not different between rest to exercise in either group, and 3) CVRco2 is similar during exercise in healthy young and older groups. NEW & NOTEWORTHY Internal carotid artery and vertebral artery blood flow responses to dynamic exercise are similar in healthy young and older individuals. Neurovascular coupling and cerebrovascular carbon dioxide reactivity, two key mechanisms mediating the cerebral blood flow responses to exercise, are generally unaffected by exercise in both healthy young and older individuals.

scholarly journals Motor cortex neurovascular coupling: inputs from ultra–high-frequency ultrasound imaging in humans

2019 ◽  
Vol 131 (5) ◽  
pp. 1632-1638 ◽  
Author(s):  
Fabien Almairac ◽  
Denys Fontaine ◽  
Thomas Demarcy ◽  
Hervé Delingette ◽  
Stéphanie Beuil ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Motor Cortex ◽  
High Frequency ◽  
Cortical Area ◽  
Neurovascular Coupling ◽  
Doppler Imaging ◽  
High Frequency Ultrasound ◽  
Local Cerebral Blood Flow ◽  
Frequency Ultrasound

OBJECTIVENeurovascular coupling reflects the link between neural activity and changes in cerebral blood flow. Despite many technical advances in functional exploration of the brain, including functional MRI, there are only a few reports of direct evidence of neurovascular coupling in humans. The authors aimed to explore, for the first time in humans, the local cerebral blood flow of the primary motor cortex using ultra–high-frequency ultrasound (UHF-US) Doppler imaging to detect low blood flow velocity (1 mm/sec).METHODSFour consecutive patients underwent awake craniotomy for glioma resection using cortical direct electrostimulation for brain mapping. The primary motor cortical area eliciting flexion of the contralateral forearm was identified. UHF-US color Doppler imaging of this cortical area was acquired at rest, during repeated spontaneous forearm flexion, and immediately after the movement’s termination. In each condition, the surface areas of the detectable vessels were measured after extraction of non–zero-velocity colored pixels and summed.RESULTSDuring movement, local cerebral blood flow increased significantly by 14.4% (range 5%–30%) compared with baseline. Immediately after the termination of movements, the local hyperemia decreased significantly by 8.6% (range 1.9%–15.7%).CONCLUSIONSTo the authors’ knowledge, this study is the first to provide a real-time demonstration of the neurovascular coupling in the human cortex by ultrasound imaging. They assume that UHF-US may be used to gather original and advanced data on brain functioning, which could be used to help in the identification of functional cortical areas during brain surgery.Clinical trial registration no.: NCT03179176 (clinicaltrials.gov)

scholarly journals Intracortical electrophysiological correlates of blood flow after severe SAH: A multimodality monitoring study

2017 ◽  
Vol 38 (3) ◽  
pp. 506-517 ◽  
Author(s):  
Brandon Foreman ◽  
David Albers ◽  
J Michael Schmidt ◽  
Cristina Maria Falo ◽  
Angela Velasquez ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Delayed Cerebral Ischemia ◽  
Neurovascular Coupling ◽  
Preliminary Evidence ◽  
Secondary Brain Injury ◽  
Poor Grade ◽  
Scalp Eeg ◽  
Rate Of Decline ◽  
Eeg Alpha

Subarachnoid hemorrhage (SAH) is a devastating form of stroke. Approximately one in four patients develop progressive neurological deterioration and silent infarction referred to as delayed cerebral ischemia (DCI). DCI is a complex, multifactorial secondary brain injury pattern and its pathogenesis is not fully understood. We aimed to study the relationship between cerebral blood flow (CBF) and neuronal activity at both the cortex and in scalp using electroencephalography (EEG) in poor-grade SAH patients undergoing multimodality intracranial neuromonitoring. Twenty patients were included, of whom half had DCI median 4.7 days (interquartile range (IQR): 4.0–5.6) from SAH bleed. The rate of decline in regional cerebral blood flow (rCBF) was significant in both those with and without DCI and occurred between days 4 and 7 post-SAH. The scalp EEG alpha-delta ratio declined early in those with DCI. In the group without DCI, CBF and cortical EEG alpha-delta ratio were correlated (r = 0.53; p <  0.01) and in the group without DCI, inverse neurovascular coupling was observed at CPP <  80 mmHg. We found preliminary evidence that as patients enter the period of highest risk for the development of DCI, the absence of neurovascular coupling may act as a possible pathomechanism in the development of ischemia following SAH.

Hourly staircase sprinting exercise “snacks” improve femoral artery shear patterns but not flow-mediated dilation or cerebrovascular regulation: A pilot study

2020 ◽  
Author(s):  
Hannah G Caldwell ◽  
Geoff B Coombs ◽  
Hossein Rafiei ◽  
Philip N Ainslie ◽  
Jonathan P. Little
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Femoral Artery ◽  
Vascular Function ◽  
Regional Blood Flow ◽  
Cerebral Metabolism ◽  
Neurovascular Coupling ◽  
Duplex Ultrasound ◽  
Transcranial Doppler Ultrasound ◽  
Flow Mediated Dilation

Healthy males (n=10; 24±4 years; BMI: 24±2 kg/m2) completed two randomized conditions separated by ≥48 hours involving 6-8.5 hours of sitting with (“stair snacks”) and without (sedentary) hourly staircase sprint interval exercise (approx. 14-20 s each). Resting blood flow and shear rates were measured in the femoral artery, internal carotid artery, and vertebral artery (Duplex ultrasound). Flow-mediated dilation (FMD) was quantified as an index of peripheral endothelial function in the femoral artery. Neurovascular coupling (NVC; regional blood flow response to local increases in cerebral metabolism) was assessed in the posterior cerebral artery (transcranial Doppler ultrasound). Femoral artery hemodynamics were higher following the active trial with no change in the sedentary trial, including blood flow (+32±23% vs. -10±28%; P=0.015 and P=0.253, respectively), vascular conductance (+32±27% vs. -15±26%; P=0.012 and P=0.098, respectively), and mean shear rate (+17±8% vs. -8±28%; P=0.004 and P=0.310, respectively). The change in FMD was not different within or between conditions (P=0.184). Global cerebral blood flow (CBF), conductance, shear patterns, and NVC were not different within or between conditions (all P>0.05). Overall, exercise “stair snacks” improve femoral artery blood flow and shear patterns but not peripheral (e.g., FMD) or cerebral (e.g., CBF and NVC) vascular function following prolonged sitting. The study was registered at ClinicalTrials.gov (NCT03374436) Key findings: ● Breaking up 8.5 hours of sitting with hourly staircase sprinting exercise “snacks” improves resting femoral artery shear patterns but not flow-mediated dilation. ● Cerebral blood flow and neurovascular coupling were unaltered following 6 hours of sitting with and without hourly exercise breaks.

A lumped parameter model of cerebral blood flow control combining cerebral autoregulation and neurovascular coupling

2012 ◽  
Vol 303 (9) ◽  
pp. H1143-H1153 ◽  
Author(s):  
Bart Spronck ◽  
Esther G. H. J. Martens ◽  
Erik D. Gommer ◽  
Frans N. van de Vosse
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Control ◽  
Cerebral Autoregulation ◽  
Neurovascular Coupling ◽  
Flow Regulation ◽  
Lumped Parameter Model ◽  
Blood Flow Regulation ◽  
Lumped Parameter ◽  
Blood Flow Control

Cerebral blood flow regulation is based on a variety of different mechanisms, of which the relative regulatory role remains largely unknown. The cerebral regulatory system expresses two regulatory properties: cerebral autoregulation and neurovascular coupling. Since partly the same mechanisms play a role in cerebral autoregulation and neurovascular coupling, this study aimed to develop a physiologically based mathematical model of cerebral blood flow regulation combining these properties. A lumped parameter model of the P2 segment of the posterior cerebral artery and its distal vessels was constructed. Blood flow regulation is exerted at the arteriolar level by vascular smooth muscle and implements myogenic, shear stress based, neurogenic, and metabolic mechanisms. In eight healthy subjects, cerebral autoregulation and neurovascular coupling were challenged by squat-stand maneuvers and visual stimulation using a checkerboard pattern, respectively. Cerebral blood flow velocity was measured using transcranial Doppler, whereas blood pressure was measured by finger volume clamping. In seven subjects, the model proposed fits autoregulation and neurovascular coupling measurement data well. Myogenic regulation is found to dominate the autoregulatory response. Neurogenic regulation, although only implemented as a first-order mechanism, describes neurovascular coupling responses to a great extent. It is concluded that our single, integrated model of cerebral blood flow control may be used to identify the main mechanisms affecting cerebral blood flow regulation in individual subjects.

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