Aging is a natural process accompanied with a progressive deterioration of cognitive functions. With an aging population, more and more elderly people are suffering from cognitive impairment. Previous studies have paid more attention to the impact of inflammation and oxidative stress on cognitive function during aging. Recently, it has been discovered that neurovascular coupling (NVC), a mechanism regulating cerebral blood flow, may play a significant role in aging-related cognitive impairment. NVC responses regulate the supply of energy substances and oxygen during brain activity, which in turn enhances cognitive function. However, as people grow older, NVC responses gradually weaken, which may be one of the mechanisms underlying aging-induced cognitive impairment. Given the important role of NVC responses in the brain, it is necessary to search for intervention methods that can improve NVC responses and promote cognitive function. Exercise is an effective means to delay aging and improve cognitive function. It also has a certain promoting effect on NVC responses. This article reviews the regulatory mechanisms of NVC responses, the relationship between NVC responses and cognitive function, and explores the effects of aging and exercise intervention on NVC responses, hoping to provide new research ideas for exercise intervention to improve NVC responses and promote cognitive function in the elderly.
Humans ; Aged ; Neurovascular Coupling/physiology* ; Aging ; Cerebrovascular Circulation/physiology* ; Cognition ; Brain

Ischemia can cause decreased cerebral neurovascular coupling, leading to a failure in the autoregulation of cerebral blood flow. This study aims to investigate the effect of varying degrees of ischemia on cerebral hemodynamic reactivity using in vivo real-time optical imaging. We utilized direct cortical stimulation to elicit hyper-excitable neuronal activation, which leads to induced hemodynamic changes in both the normal and middle cerebral artery occlusion (MCAO) ischemic stroke groups. Hemodynamic measurements from optical imaging accurately predict the severity of occlusion in mild and severe MCAO animals. There is neither an increase in cerebral blood volume nor in vessel reactivity in the ipsilateral hemisphere (I.H) of animals with severe MCAO. The pial artery in the contralateral hemisphere (C.H) of the severe MCAO group reacted more slowly than both hemispheres in the normal and mild MCAO groups. In addition, the arterial reactivity of the I.H in the mild MCAO animals was faster than the normal animals. Furthermore, artery reactivity is tightly correlated with histological and behavioral results in the MCAO ischemic group. Thus, in vivo optical imaging may offer a simple and useful tool to assess the degree of ischemia and to understand how cerebral hemodynamics and vascular reactivity are affected by ischemia.
Animals ; Arteries ; Blood Volume ; Cerebrovascular Circulation ; Hemodynamics* ; Homeostasis ; Infarction, Middle Cerebral Artery* ; Ischemia ; Middle Cerebral Artery* ; Neurons ; Neurovascular Coupling ; Optical Imaging ; Rodentia* ; Stroke

In this paper a new type of cerebral circulation is introduced, including the basic principal, parameter algorithms and equipment design. The analyzer is developed on the basis of previous cerebral circulation analyzer and combined with the latest development of hemodynamics. It has the advantages of previous analyzer and overcomes its shortcomings frequently encountered in clinical that unable to finish the analysis without detection of all the intracranial vessels. It provides new functional module and adds indices such as hydraulic power, carotidshear stress, comprehensive index etc. This analyzer can be used for cerebral circulation dynamic analysis and auxiliary diagnosis of cerebrovascular diseases.
Algorithms ; Cerebrovascular Circulation ; Cerebrovascular Disorders ; diagnosis ; Equipment Design ; Hemodynamics ; Humans

Blood Pressure ; Cerebrovascular Circulation ; Circle of Willis ; Humans

In anesthetized normocapnic and normotensive dogs, the effect of arterial hypoxemia on cerebral blood flow and oxidative carbohydrate metabolism was studied. The results are as follows: 1) The hypoxic vasodilatory effect on cerevral vessels is intact even at profound systemic hypoxemia(Pao2 30 torr) if Paco2 is controlled within normal limits. 2) CMRO2 did not significantly increase above the normal even during profound arterial hopoxemis, indicating that CMRO2 levels are poor indices of hypoxia. 3) A disporportinately high glycolysis at Pao2 of 50 torr suggested early cerebral metabolic changes which became more marked with further decrease in Pao2. 4) One hour after restitution of normoxia, however, carebral blood flow and metabolism manifested complete recovery. 6) It is concluded that a transient(20 minutes) profoun systemic arterial hypoxemia does not produce prolonged disorder of cerebral blood flow and oxidative carbohydrate metabolism provided that the cerebral perfusion pressure is kept normal.
Animals ; Anoxia* ; Carbohydrate Metabolism ; Cerebrovascular Circulation* ; Dogs ; Glycolysis ; Metabolism*

BACKGROUNDThe feasibility of the mapping of quantitative cerebral blood flow (CBF) named flow-sensitive alternating inversion recovery exempting separate T1 measurement (FAIREST) is still controversial. This study aimed to evaluate the reliability of FAIREST in the measurement of regional CBF (rCBF) in healthy volunteers.

METHODSEighteen healthy volunteers underwent magnetic resonance (MR) scanning with the sequence of FAIREST. While they were at rest, rCBF values were obtained in various brain regions of interest (ROIs). The same scheme was repeated on every subject after two weeks. Statistical analysis was made to determine the effect of location, scan and side on the measurement of rCBF.

RESULTSThe mean CBF values were (122+/-28) ml x (100 g)(-1) x min(-1) and (43+/-10) ml x (100 g)(-1) x min(-1) in the gray and white matter respectively. There was significant main effect of location (t=-12.5, P<0.01), but no significant effect of side. Paired t-test of ROIs in the same slice showed no significant difference in most sites between two scans, except in the gray matter of the bilateral frontal lobes (t=2.18-2.34, P <0.05). However, the rCBF values of the same structure obtained from different slices showed a significant difference (t=-3.49, P<0.01).

CONCLUSIONFAIREST is a reliable technique in the measurement of rCBF, but different imaging slice may affect the agreement of rCBF across the scans.

Cerebrovascular Circulation ; physiology ; Humans ; Microcomputers ; Tomography, X-Ray Computed ; methods

OBJECTIVETo explore the mechanism of moxibustion at Zusanli (ST 36) and Xuanzhong (GB 39) treatment of ischemic apoplexy, and to evaluate the clinical therapeutic effect.

METHODSWith the design of sequential trial, the patients were divided into a treatment group and a control group. The treatment group were treated by addition with moxibustion at Zusanli (ST 36) and Xuanzhong (GB 39) on the basis of basic expectant treatment, once each day, for 20 consecutive days; and the control group with basic expectant treatment for 20 days. Changes of cerebrovascular functions before and after treatment were investigated by transcranial Doppler ultrasound (TCD) in the matched-pair's patients of ischemic apoplexy; the clinical therapeutic effect was assessed by nervous function defect before and after treatment.

RESULTSAll the test lines of the research targets reached to the effective margin the sequential trial figure, with a significant difference as compared with the control group (P < 0.05).

CONCLUSIONMoxibustion at Zusanli (ST 36) and Xuanzhong (GB 39) has good regulative action on cerebral vasomotorial response, auto-regulation of cerebral blood flow, and establishment of collateral circulation, and improves recovery nervous functions.

Arterial spin labeling (ASL) technique is a kind of perfusion functional magnetic resonance imaging method that is based on endogenous contrast, and it can measure cerebral blood flow (CBF) noninvasively. The ASL technique has advantages of noninvasiveness, simplicity and relatively lower costs so that it is more suitable for longitudinal studies compared with previous perfusion methods, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), CT and the contrast agent based magnetic resonance perfusion imaging. This paper mainly discusses the current clinical applications of ASL in brain diseases as cerebrovascular diseases, brain tumors, Alzheimer's disease and epilepsy, etc.
Animals ; Brain Diseases ; diagnosis ; Brain Neoplasms ; diagnosis ; Cerebrovascular Circulation ; Cerebrovascular Disorders ; diagnosis ; Humans ; Magnetic Resonance Imaging ; methods ; Perfusion ; Spin Labels

OBJECTIVEWe used functional magnetic resonance imaging (fMRI) to explore the effects of noxious coldness and non-noxious warmth on the magnitude of cerebral cortex activation during intraoral stimulation with water.

METHODSSix male and female subjects were subjected to whole-brain fMRI during the phasic delivery of non-noxious hot (23 °C) and no- xious cold (4 °C) water intraoral stimulation. A block-design blood oxygenation level-dependent fMRI scan covering the entire brain was also carried out.

RESULTSThe activated cortical areas were as follows: left pre-/post-central gyrus, insula/operculum, anterior cingulate cortex (ACC), orbital frontal cortex (OFC), midbrain red nucleus, and thalamus. The activated cortical areas under cold condition were as follows: left occipital lobe, premotor cortex/Brodmann area (BA) 6, right motor language area BA44, lingual gyrus, parietal lobule (BA7, 40), and primary somatosensory cortex S I. Comparisons of the regional cerebral blood flow response magnitude were made among stereotactically concordant brain regions that showed significant responses under the two conditions of this study. Compared with non-noxious warmth, more regions were activated in noxious coldness, and the magnitude of activation in areas produced after non-noxious warm stimulation significantly increased. However, ACC only significantly increased the magnitude of activation under noxious coldness stimulation.

CONCLUSIONResults suggested that a similar network of regions was activated common to the perception of pain and no-pain produced by either non-noxious warmth or noxious coldness stimulation. Non-noxious warmth also activated more brain regions and significantly increased the response magnitude of cerebral-cortex activation compared with noxious coldness. Noxious coldness stimulation further significantly increased the magnitude of activation in ACC areas compared with noxious warmth.