scholarly journals Evidence that N-acetyaspartylglutamate is the astrocyte-targeted neurovascular coupling agent that regulates slow tonic control of brain blood flow

2016 ◽  
Vol 1 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Morris H Baslow ◽  
David N Guilfoyle
Keyword(s):  
Blood Flow ◽  
Coupling Agent ◽  
Neurovascular Coupling ◽  
Brain Blood Flow

scholarly journals Tonic Local Brain Blood Flow Control by Astrocytes Independent of Phasic Neurovascular Coupling

2015 ◽  
Vol 35 (39) ◽  
pp. 13463-13474 ◽  
Author(s):  
D. G. Rosenegger ◽  
C. H. T. Tran ◽  
J. I. Wamsteeker Cusulin ◽  
G. R. Gordon
Keyword(s):  
Blood Flow ◽  
Flow Control ◽  
Neurovascular Coupling ◽  
Brain Blood Flow ◽  
Blood Flow Control ◽  
Local Brain

Heterogeneity of Cerebral Blood Flow: a Fractal Approach

2000 ◽  
Vol 39 (02) ◽  
pp. 37-42 ◽  
Author(s):  
P. Hartikainen ◽  
J. T. Kuikka
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Fractal Dimension ◽  
Frontal Lobe ◽  
Fractal Analysis ◽  
Relative Dispersion ◽  
Emission Computed Tomography ◽  
Brain Blood Flow ◽  
Healthy Controls ◽  
Fractal Approach

Summary Aim: We demonstrate the heterogeneity of regional cerebral blood flow using a fractal approach and singlephoton emission computed tomography (SPECT). Method: Tc-99m-labelled ethylcysteine dimer was injected intravenously in 10 healthy controls and in 10 patients with dementia of frontal lobe type. The head was imaged with a gamma camera and transaxial, sagittal and coronal slices were reconstructed. Two hundred fifty-six symmetrical regions of interest (ROIs) were drawn onto each hemisphere of functioning brain matter. Fractal analysis was used to examine the spatial heterogeneity of blood flow as a function of the number of ROIs. Results: Relative dispersion (= coefficient of variation of the regional flows) was fractal-like in healthy subjects and could be characterized by a fractal dimension of 1.17 ± 0.05 (mean ± SD) for the left hemisphere and 1.15 ± 0.04 for the right hemisphere, respectively. The fractal dimension of 1.0 reflects completely homogeneous blood flow and 1.5 indicates a random blood flow distribution. Patients with dementia of frontal lobe type had a significantly lower fractal dimension of 1.04 ± 0.03 than in healthy controls. Conclusion: Within the limits of spatial resolution of SPECT, the heterogeneity of brain blood flow is well characterized by a fractal dimension. Fractal analysis may help brain scientists to assess age-, sex- and laterality-related anatomic and physiological changes of brain blood flow and possibly to improve precision of diagnostic information available for patient care.

Effects of smoking marijuana on focal attention and brain blood flow

2007 ◽  
Vol 22 (3) ◽  
pp. 135-148 ◽  
Author(s):  
Daniel S. O'Leary ◽  
Robert I. Block ◽  
Julie A. Koeppel ◽  
Susan K. Schultz ◽  
Vincent A. Magnotta ◽  
...  
Keyword(s):  
Blood Flow ◽  
Brain Blood Flow ◽  
Focal Attention ◽  
Smoking Marijuana

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.

Modeling Cerebral Blood Flow and Ventilation Instability due to CO2

2021 ◽  
Author(s):  
Stanley M. Yamashiro ◽  
Takahide Kato
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Current Model ◽  
Respiratory Control ◽  
Breath Hold ◽  
Chronic Obstructive ◽  
Brain Blood Flow ◽  
Linear Interaction ◽  
Non Linear ◽  
Flow Changes

A minimal model of cerebral blood flow and respiratory control was developed to describe hypocapnic and hypercapnic responses. Important non-linear properties such as cerebral blood flow changes with arterial partial pressure of carbon dioxide (PaCO2) and associated time dependent circulatory time delays were included. It was also necessary to vary cerebral metabolic rate as a function of PaCO2. The cerebral blood flow model was added to a previously developed respiratory control model to simulate central and peripheral controller dynamics for humans. Model validation was based on previously collected data. The variable time delay due to brain blood flow changes in hypercapnia was an important determinant of predicted instability due to non-linear interaction in addition to linear loop gain considerations. Peripheral chemoreceptor gains above a critical level, but within normal limits, was necessary to produce instability. Instability was observed in recovery from hypercapnia and hypocapnia. The 20 sec breath-hold test appears to be a simple test of brain blood flow mediated instability in hypercapnia. Brain blood flow was predicted to play an important role with non-linear properties. There is an important interaction predicted by the current model between central and peripheral control mechanisms related to instability in hypercapnia recovery. Post hyperventilation breathing pattern can also reveal instability tied to brain blood flow. Previous data collected in patients with chronic obstructive lung disease was closely fitted with the current model and instability predicted. Brain vascular volume was proposed as a potential cause of instability despite cerebral autoregulation promoting constant brain flow.

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