The effect of acetazolamide on the changes of cerebral blood flow and oxygen metabolism during visual stimulation

Acetazolamide, a carbonic anhydrase inhibitor, has an anticonvulsant effect which may result from a decrease in the efficacy of synaptic transmission due to a decrease of pH. Our previous study showed that acetazolamide induced a significant increase in global and regional cerebral blood flow (CBF), but caused no significant change in the cerebral metabolic rate of oxygen (CMRO(2)). To investigate the effect of acetazolamide on the responses of CBF and CMRO(2) during neural stimulation, we used positron emission tomography to measure CBF and CMRO(2) in six normal volunteers at the fixation-only baseline visual state and during visual stimulation before and after administration of 1 g of acetazolamide. Visual stimulation induced a significant increase in CBF (33%) in the visual cortex compared with baseline values, but caused no significant change in CMRO(2), while no significant change in global CBF or CMRO(2) was found. During visual stimulation after acetazolamide administration, both global and visual cortical CBF and CMRO(2) showed similar changes compared with the respective baseline values (37 and 65% increases in CBF and 8 and 16% decreases in CMRO(2), respectively). When corrected by the global values, the magnitudes of the CBF and CMRO(2) responses to visual stimulation after acetazolamide administration were less than those before (20% vs 38% in CBF and -9% vs 3% in CMRO(2)). Considering our previous observation that the effect of acetazolamide was similar throughout cerebral cortical regions, we suggest that acetazolamide decreases the responses of both CBF and CMRO(2) during visual stimulation, which indicates that this drug may affect neuronal excitability.     

深部脑电刺激治疗帕金森病的FDGPET研究

目的研究双侧丘脑底核慢性电刺激术对晚期帕金森病患者脑局部糖代谢的影响及作用机制.方法对7例进行双侧STN DBS的晚期帕金森病患者,在术前和术后1个月电刺激条件下,分别进行18F-脱氧葡萄糖(18F-FDG)PET显像和UPDRS评分,通过SPM进行数据分析.结果 7例患者临床症状明显改善,同时FDG PET显像提示双侧豆状核、脑干、顶枕部、运动前区(BA6)及扣带回的脑代谢增加,而前额叶底部及海马的脑代谢减少(P<0.05).结论双侧STN DBS可使PD患者临床症状改善.FDG PET可作为PD进行STN治疗适应证选择的方法之一.     

Changes of cerebral blood flow, oxygenation, and oxidative metabolism during graded motor activation.

In the present studies fMRI and a hypercapnic calibration procedure were used to monitor simultaneous changes in cerebral blood flow (CBF), cerebral blood oxygenation, and cerebral metabolic rate of oxygen (CMRO(2)) during activation in the sensorimotor cortex. In the first set of experiments seven volunteers performed bilateral, self-paced finger tapping and in the second set of experiments six volunteers performed bilateral finger tapping with six different frequencies (0.5-3 Hz). During the latter task relative CBF and BOLD signal intensity changes varied linearly as a function of stimulus frequency. In good agreement with recent PET and fMRI data increases in CMRO(2) were smaller than the corresponding changes in CBF during self-paced finger tapping and at all levels of graded motor activation. At a single level of activation and during graded activation there was a positive linear relationship between CBF and CMRO(2) with ratios of approximately 3:1. Comparable proportionality constants have been found in the visual cortex and primary sensory cortex, indicating similarities between the relationship of CBF and CMRO(2) in various cortical regions.     

Distinct oscillatory STN-cortical loops revealed by simultaneous MEG and local field potential recordings in patients with Parkinson's disease

Neuronal oscillations are assumed to play a pivotal role in the pathophysiology of Parkinson's disease (PD). Neurons in the subthalamic nucleus (STN) generate oscillations which are coupled to rhythmic population activity both in other basal ganglia nuclei and cortical areas. In order to localize these cortical areas, we recorded local field potentials (LFPs) and magnetoencephalography (MEG) simultaneously in PD patients undergoing surgery for deep brain stimulation (DBS). Patients were withdrawn from antiparkinsonian medication and recorded at rest. We scanned the entire brain for oscillations coherent with LFPs recorded from the STN with a frequency domain beamformer. Coherent activity in the low (12-20 Hz) and high (20-35 Hz) beta range was found in the ipsilateral sensorimotor and the premotor cortex. Coherence in the alpha range (7-12 Hz) was observed at various locations in the ipsilateral temporal lobe. In a subset of subjects, the superior temporal gyrus consistently showed coherent alpha oscillations. Our findings provide new insights into patterns of frequency-specific functional connectivity between basal ganglia and cortex and suggest that simultaneous inter-regional interactions may be segregated in the frequency domain. Furthermore, they demonstrate that simultaneous MEG-LFP recordings are a powerful tool to study interactions between brain areas in PD patients undergoing surgery for DBS.     

Regional differences in the coupling of cerebral blood flow and oxygen metabolism changes in response to activation: implications for BOLD-fMRI

Functional magnetic resonance imaging (fMRI) based on blood oxygenation level dependent (BOLD) signal changes is a sensitive tool for mapping brain activation, but quantitative interpretation of the BOLD response is problematic. The BOLD response is primarily driven by cerebral blood flow (CBF) changes, but is moderated by M, a scaling parameter reflecting baseline deoxyhemoglobin, and n, the ratio of fractional changes in CBF to cerebral metabolic rate of oxygen consumption (CMRO(2)). We compared M and n between cortical (visual cortex, VC) and subcortical (lentiform nuclei, LN) regions using a quantitative approach based on calibrating the BOLD response with a hypercapnia experiment. Although M was similar in both regions (~5.8%), differences in n (2.21+/-0.03 in VC and 1.58+/-0.03 in LN; Cohen d=1.71) produced substantially weaker (~3.7x) subcortical than cortical BOLD responses relative to CMRO(2) changes. Because of this strong sensitivity to n, BOLD response amplitudes cannot be interpreted as a quantitative reflection of underlying metabolic changes, particularly when comparing cortical and subcortical regions.     

Caffeine-induced uncoupling of cerebral blood flow and oxygen metabolism: a calibrated BOLD fMRI study

Although functional MRI (fMRI) based on blood oxygenation level-dependent (BOLD) signal changes is a sensitive tool for mapping brain activation, quantitative studies of the physiological effects of pharmacological agents using fMRI alone are difficult to interpret due to the complexities inherent in the BOLD response. Hypercapnia-calibrated BOLD methodology is potentially a more powerful physiological probe of brain function, providing measures of the changes in cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen (CMRO(2)). In this study, we implemented a quantitative R(2)* approach for assessing the BOLD response to improve the stability of repeated measurements, in combination with the calibrated BOLD method, to examine the CBF and CMRO(2) responses to caffeine ingestion. Ten regular caffeine consumers were imaged before and after a 200-mg caffeine dose. A dual-echo arterial spin labeling technique was used to measure CBF and BOLD responses to visual stimulation, caffeine consumption and mild hypercapnia. For a region of interest defined by CBF activation to the visual stimulus, the results were: hypercapnia increased CBF (+46.6%, +/-11.3, mean and standard error), visual stimulation increased both CBF (+47.9%, +/-2.9) and CMRO(2) (+20.7%, +/-1.4), and caffeine decreased CBF (-34.5%, +/-2.6) with a non-significant change in CMRO(2) (+5.2%, +/-6.4). The coupling between CBF and CMRO(2) was significantly different in response to visual stimulation compared to caffeine consumption. A calibrated BOLD methodology using R(2) * is a promising approach for evaluating CBF and CMRO(2) changes in response to pharmacological interventions.     

Time-related increase of oxygen utilization in continuously activated human visual cortex

Oxygen utilization increase is fractionally much less than that seen in glucose metabolism and blood flow soon after onset of neuronal activation, however its behavior during continued activation is less certain. We evaluated the effects of 25 min of visual stimulation on CBF, CMRO(2), and OEF using [(15)O] water and [(15)O] oxygen PET. Seven healthy volunteers underwent a PET session consisting of serial [(15)O] water and [(15)O] oxygen scans at the fixation-only baseline visual state and after 1, 13, and 25 min of the continuous visual stimulation using a black-white vertical grating. CBF, CMRO(2), and OEF values were calculated for the entire brain and for regions of interest in visual cortex centered over the area of activation. After 1 min of stimulation, CMRO(2) increased only 4.7% compared to baseline and CBF increased 40.7%. However, after 25 min of stimulation the increase in CMRO(2) compared to baseline was 15.0%, having tripled from that measured at 1 min (P < 0.05). CBF did not significantly change during this time. OEF was 48.3% at baseline. It decreased to 37.1% after 1 min of visual stimulation (P < 0.01) and then returned almost to baseline values after 25 min of activation OEF (45.7%). There were no significant variations in whole-brain values during the study. We suggest that in the activated brain, the increased energy demands initially are not fully met with oxidative metabolism and must predominantly be supported by increased glycolysis. With continued activation, oxygen utilization increases reducing the need for excess glycolysis.     

急性饮酒对青年人记忆功能相关脑区CBF及OEF影响的多模态磁共振研究

目的利用三维伪连续式动脉自旋标记(three-dimensional pseudo-continuous arterial spin labeling,3D pCASL)和非对称基于自旋回波的回波平面成像(asymmetric spine echo-based echo plane imaging,ASE EPI)研究急性饮酒对健康青年人记忆功能相关脑区脑血流灌注(cerebral blood flow,CBF)、氧摄取分数(oxygen extraction fraction,OEF)的影响,分析不同剂量急性饮酒后健康志愿者记忆功能相关脑区CBF与OEF的关系。材料与方法29名健康志愿者分别摄入不同剂量的白酒,饮酒后,抽血检测血液酒精浓度(blood alcohol concentration,BAC),按照BAC≥0.04%、0.06%、0.08%分为低、中、高浓度组。所有受试者分别于饮酒前及饮酒后30 min进行记忆功能评价并行MRI扫描,饮酒前数据作为对照组。对饮酒前、后左侧额中回、顶叶、枕叶皮层、双侧扣带回、海马、杏仁核及小脑半球等记忆功能相关脑区的CBF和OEF进行比较分析。结果(1)饮酒后30 min与饮酒前相比,左侧额中回、顶叶、枕叶皮层、双侧扣带回、海马、杏仁核CBF增加(P<0.05),双侧小脑半球CBF减低(P<0.05)。饮酒后30 min,不同剂量组间左侧额中回、顶叶、枕叶皮层、双侧扣带回、海马、杏仁核的平均CBF差异有统计学意义(P<0.05)。(2)饮酒后30 min与饮酒前相比,左侧额中回、顶叶、枕叶皮层、双侧扣带回、海马OEF减低(P<0.05),双侧小脑半球OEF增加(P<0.05)。饮酒后30 min,不同剂量组间左侧额中回、顶叶、枕叶皮层、双侧扣带回、海马、小脑半球的平均OEF差异有统计学意义(P<0.05)。结论饮酒后记忆功能相关脑区的CBF、OEF呈负相关关系,脑组织氧供给与氧利用处于动态平衡。饮酒后记忆功能相关脑区脑血流和脑代谢信息的改变,在揭示酒精对记忆功能相关脑区的作用机制有一定的意义。     

Frequency-correlated decreases of motor cortex activity associated with subthalamic nucleus stimulation in Parkinson's disease

According to the classical model of basal ganglia organization, deep brain stimulation (DBS) in the subthalamic nucleus (STN) for the treatment of Parkinson's disease (PD) blocks overactive excitatory projections to inhibitory basal ganglia output structures. This would release the break on thalamofrontal neurons alleviating the poverty of movement, the hallmark of PD. Such parallels to a functional lesion certainly simplify the mechanism of STN DBS. Here, we applied parametric analyses of H2(15)O positron emission tomography (PET) scans at rest while systematically varying stimulation frequency in 6 patients with STN DBS for akinetic PD. A strong positive correlation of rCBF to increasing stimulation frequency was detected around the STN bilaterally. More importantly, we show that gradual increases in STN stimulation frequency are tightly correlated with decreases in motor cortex activity. This demonstrates an active modulation of resting activity within the subcortical stimulation target and within motor cortex by STN DBS. Rather than a possible downstream effect, we propose to consider the tight correlations between DBS frequency and motor cortex activity in the context of an upstream modulation of direct efferents to the STN from primary motor and premotor cortices.     

电刺激诱发肢体持续麻木感静息态fMRI研究

目的 采用静息态fMRI (rs-fMRI)比率低频振幅 (fALFF)检测电刺激诱发肢体持续麻木感脑功能变化情况,探讨持续性麻木脑机制。方法 对21名健康成年志愿者有无电刺激分别行静息态fMRI扫描,并要求被试对同一脉冲电刺激行麻木感强度评分。通过fALFF算法对有无电刺激脑fALFF值进行分析,并获得两者显著差异脑区,进一步将给予电刺激脑fALFF与个体麻木感强度评分作相关分析。结果 与无电刺激比较,给予电刺激fALFF值显著增强脑区：额叶内侧皮质、前扣带回、两侧颞中回、两侧颞下回和右侧颞极；显著减弱的脑区：楔前叶/后扣带回、右侧小脑。给予电刺激脑fALFF与个体麻木感评分显著正相关的脑区有楔前叶/后扣带回和左侧颞中回；显著负相关脑区有右侧额极和左侧颞下回。结论 电刺诱发肢体持续麻木感涉及感觉运动、情绪和认知功能相关脑区,且与默认网络脑区密切相关,楔前叶 /后扣带回、颞叶及额叶部分脑区与个体麻木感差异性相关,本研究为探讨麻木感相关脑机制提供新的范式。     

Confirmation of functional zones within the human subthalamic nucleus: patterns of connectivity and sub-parcellation using diffusion weighted imaging

The subthalamic nucleus (STN) is a small, glutamatergic nucleus situated in the diencephalon. A critical component of normal motor function, it has become a key target for deep brain stimulation in the treatment of Parkinson's disease. Animal studies have demonstrated the existence of three functional sub-zones but these have never been shown conclusively in humans. In this work, a data driven method with diffusion weighted imaging demonstrated that three distinct clusters exist within the human STN based on brain connectivity profiles. The STN was successfully sub-parcellated into these regions, demonstrating good correspondence with that described in the animal literature. The local connectivity of each sub-region supported the hypothesis of bilateral limbic, associative and motor regions occupying the anterior, mid and posterior portions of the nucleus respectively. This study is the first to achieve in-vivo, non-invasive anatomical parcellation of the human STN into three anatomical zones within normal diagnostic scan times, which has important future implications for deep brain stimulation surgery.     

Spatial extent of oxygen metabolism and hemodynamic changes during functional activation of the rat somatosensory cortex

The spatial extent of the changes in oxy-hemoglobin (HbO), deoxy-hemoglobin (HbR), total hemoglobin concentration (HbT), cerebral blood flow (CBF), and the cerebral metabolic rate of oxygen (CMRO(2)) in response to forepaw and whisker stimulation were compared in the rat somatosensory cortex using a combination of multi-wavelength reflectance imaging and laser speckle contrast imaging of cerebral blood flow. The spatial extents of the response of each hemodynamic parameter and CMRO(2) were found to be comparable at the time of peak response, and at early times following stimulation onset, the spatial extent of the change in HbR was smaller than that of HbO, HbT, CBF, and CMRO(2). In addition, a slight spatial dependence was found in the power law coefficient relating changes in CBF and HbT. Although the CMRO(2) response is a metabolic measure and thus expected to have a more localized response than the hemodynamic parameters, the results presented here suggest that this may not be the case in general, possibly due to the increased sensitivity of optical imaging techniques to superficial cortical layers where the lateral extent of the metabolic and neuronal activation is larger compared to that in layer IV. In addition, we found that the measured spatial extent of the CMRO(2) changes was insensitive to assumptions made in the calculation of the CMRO(2) changes such as baseline hemoglobin concentrations, vascular weighting constants, and wavelength dependence of tissue scattering. Multi-parameter full field imaging of the functional response provides a more complete picture of the hemodynamic response to functional activation including the spatial and temporal estimation of CMRO(2) changes.     

Stimulation of subthalamic nucleus inhibits emotional activation of fusiform gyrus

In patients with Parkinson's disease, deep brain stimulation of the subthalamic nucleus is known to impair their ability to correctly identify facial expressions of negative emotions. This difficulty exists only when the stimulator is active. The reason for the impairment is unknown. To test the hypothesis that the stimulation itself is responsible, we used positron emission tomography to compare functional activations of brain regions in nine patients with Parkinson's disease treated with surgically implanted electrodes into both subthalamic nuclei, and 22 healthy volunteers. Both groups viewed images with neutral or emotional content from Aarhus University's standard Empathy Picture System () with 360 images of people in pleasant, unpleasant or neutral real-life situations, presenting either the situations or close-ups of the facial expressions of the people involved. Both groups, the patients with stimulation OFF and the healthy volunteers, had raised regional blood flow rates (rCBF) in the right fusiform gyrus when they viewed emotionally expressive faces compared to neutral faces. With stimulation turned on, this response was significantly inhibited in the patients because of a raised rCBF at baseline during the neutral faces. Stimulation of the STN did not alter fusiform reaction to emotionally pregnant scenes; nor did healthy volunteers and patients react differently to these stimuli regardless of stimulation status. Also, STN stimulation raised the emotional activation of the anterior cingulate and lowered the activity of the putamen. The findings suggest that the stimulation of the subthalamic nucleus interferes with the integration of specific neocortical networks involved in the recognition of facial expressions.     

基于三维准连续动脉自旋标记成像评估单侧突发感觉神经性耳聋患者脑血流灌注改变

目的 基于三维准连续动脉自旋标记成像（3D pCASL）评估单侧突发感觉神经性耳聋（SSNHL）患者脑血流灌注改变。方法 对34例临床诊断单侧SSNHL患者（SSNHL组）和33名年龄、性别及受教育年限与之匹配的健康对照者（HC组）行3D pCASL扫描；评估SSNHL组平均听力阈值（PTA），以中文版耳鸣残疾量表（THI）、耳鸣评价量表（TEQ）、耳鸣响度视觉模拟评分法（VAS）、抑郁自评量表（SDS）及焦虑自评量表（SAS）观察其心理声学特征及情绪状况；基于体素水平分析组间脑血流量（CBF）存在差异的脑区，提取其空间标准化及归一化后的相对CBF （rCBF），分析SSNHL组异常灌注脑区rCBF与THI、TEQ、VAS、SDS及SAS评分的相关性。结果 与HC组相比，SSNHL组右侧三角部额下回及后扣带回CBF增高，左侧楔前叶、双侧中央后回、右侧额中回及右侧顶上小叶CBF减低（P均<0.05）。SSNHL组左侧楔前叶及左侧中央后回rCBF与SDS评分呈负相关（r=－0.441、－0.437，P=0.015、0.016）；SSNHL组异常灌注脑区的rCBF与其余量表评分均无明显相关（P均>0.05）。结论 单侧SSNHL患者右侧额叶、双侧顶叶及后扣带回等多个脑区存在灌注改变。     

Hypothermia effects on neurovascular coupling and cerebral metabolic rate of oxygen

Neuronal activation is accompanied by a local increase in cerebral blood flow (CBF) and in cerebral metabolic rate of oxygen (CMRO(2)), caused by neurovascular and neurometabolic coupling. Hypothermia is used as a neuroprotective approach in surgical patients and therapeutically after cardiac arrest or stroke. The effect of hypothermia on neurovascular coupling is of interest for evaluating brain function in these patients, but has not been determined so far. It is not clear whether functional hyperaemia actually operates at subnormal temperatures. In addition, decreasing brain temperature reduces spontaneous CMRO(2) following a known quantitative relationship (Q(10)). Q(10) determination may serve to validate a recently introduced CMRO(2) measurement approach relying on optical measurements of CBF and hemoglobin concentration. We applied this method to investigate hypothermia in a functional study of the somatosensory cortex. Anesthetized Wistar rats underwent surgical implantation of a closed cranial window. Using laser Doppler flowmetry and optical spectroscopy, relative changes in CBF and hemoglobin concentration were measured continuously. At the same time, an electroencephalogram (EEG) was recorded from the measurement site. By the application of ice packs, whole-body hypothermia was induced, followed by rewarming. Spontaneous EEG, CBF and CMRO(2) were measured, interleaved by blocks of electrical forepaw stimulation. The Q(10) obtained from spontaneous CMRO(2) changes of 4.4 (95% confidence interval 3.7-5.1) was close to published values, indicating the reliability of the CMRO(2) measurement. Lowering brain temperature decreased functional changes of CBF and CMRO(2) as well as amplitudes of somatosensory evoked potentials (SEP) to the same degree. In conclusion, neurovascular and neurometabolic coupling is preserved during hypothermia.     

播散性皮层抑制猫脑模型的磁共振功能成像研究

目的：用血氧水平依赖性磁共振功能成像（BOLD-fMRI）技术研究KCl诱导猫脑模型的播散性皮层抑制（SCD）。方法：雌猫6只,双侧额窦开颅并充填琼脂糖凝胶,两侧上侧裂回上方开颅,以备分别注入KCl凝胶和生理盐水凝胶。在1.5T场强下分别行静息期、KCl刺激期及对侧生理盐水刺激期BOLD-fMRI采集。结果：KCl刺激区上侧裂回及邻近边缘回脑皮层可见脑功能激活区者5例,并播及到同侧边缘回后部,而对侧大脑半球均无脑激活区。感兴趣区时间-信号强度曲线显示注入KCl后,fMRI信号立即显著增高,并维持于高水平较长时间。结论：BOLD-fMRI能准确检测出SCD伴发的神经血管耦联现象—脑血流量的变化,是研究SCD的可靠方法。     

Effects of dopamine receptor blockade on cerebral blood flow response to somatosensory stimulation in the unanesthetized rat

Local cerebral blood flow (CBF) was determined in 30 cerebral structures, including four structures of the whisker-to-barrel cortex sensory pathway, by the quantitative autoradiographic [(14)C]iodoantipyrine method during unilateral vibrissal stimulation in rats administered 0.1 or 1.0 mg/kg haloperidol or its control vehicle intravenously. The low dose of haloperidol had no significant effects on resting CBF or its enhancement by vibrissal stimulation. By standard t tests, the high dose statistically significantly lowered baseline CBF in frontal and visual cortex, hippocampus, dentate gyrus, inferior olive, cerebellar cortex, and the ventral posteromedial (VPM) thalamic nucleus on the unstimulated side, and raised baseline CBF in the lateral habenula; however, these changes lost statistical significance after Bonferroni correction for multiple comparisons. Neither dose had any effects on the increases in CBF evoked by vibrissal stimulation in the principal sensory trigeminal nucleus and barrel cortex, but the higher dose statistically significantly enhanced the percent increases in CBF due to the sensory stimulation in the spinal trigeminal nucleus and VPM thalamic nucleus. These results do not support a role for direct dopaminergic vasoactive mechanisms in the increases in CBF associated with neuronal functional activation.     

Time-dependent correlation of cerebral blood flow with oxygen metabolism in activated human visual cortex as measured by fMRI

The aim of this study was to investigate the relationship between relative cerebral blood flow (delta CBF) and relative cerebral metabolic rate of oxygen (delta CMRO(2)) during continuous visual stimulation (21 min at 8 Hz) with fMRI biophysical models by simultaneously measuring of BOLD, CBF and CBV fMRI signals. The delta CMRO(2) was determined by both a newly calibrated single-compartment model (SCM) and a multi-compartment model (MCM) and was in agreement between these two models (P>0.5). The duration-varying delta CBF and delta CMRO(2) showed a negative correlation with time (r=-0.97, P<0.001); i.e., delta CBF declines while delta CMRO(2) increases during continuous stimulation. This study also illustrated that without properly calibrating the critical parameters employed in the SCM, an incorrect and even an opposite appearance of the flow-metabolism relationship during prolonged visual stimulation (positively linear coupling) can result. The time-dependent negative correlation between flow and metabolism demonstrated in this fMRI study is consistent with a previous PET observation and further supports the view that the increase in CBF is driven by factors other than oxygen demand and the energy demands will eventually require increased aerobic metabolism as stimulation continues.     

Deep brain stimulation for advanced Parkinson's disease

Deep brain stimulation (DBS) is a new and promising technique for the treatment of movement disorders. Medically intractable Parkinson's disease (PD) is one of the most common indications for DBS. There are three possible subcortical targets for PD, depending on the symptomatology (i.e., the motor subdivision of the thalamus, the globus pallidus internus, the subthalamic nucleus [STN]). Thalamic stimulation has been well established as a safe and effective treatment for essential tremor and the tremor associated with PD. Globus pallidus internus and STN DBS are being investigated for the treatment of all the cardinal signs of PD. This article describes the pathophysiology of PD, the surgical treatment history of PD, surgical techniques used for DBS implants, and the role the perioperative nurse has in the care of the patients undergoing these procedures.     

Assessment of normalized cerebral blood flow and its connectivity with migraines without aura during interictal periods by arterial spin labeling

BackgroundMigraine constitutes a global health burden, and its pathophysiology is not well-understood; research evaluating cerebral perfusion and altered blood flow between brain areas using non-invasive imaging techniques, such as arterial spin labeling, have been scarce. This study aimed to assess cerebral blood flow (CBF) and its connectivity of migraine.MethodsThis study enrolled 40 patients with episodic migraine without aura (MwoA), as well as 42 healthy patients as control (HC). Two groups of normalized CBF and CBF connectivity were compared, and the relationship between CBF variation and clinical scale assessment was further evaluated.ResultsIn comparison to HC subjects, MwoA patients exhibited higher CBF in the right middle frontal orbital gyrus (ORBmid.R) and the right middle frontal gyrus, while that in Vermis_6 declined. The increased CBF of ORBmid.R was positively correlated with both the Visual Light Sensitivity Questionnaire-8 (VLSQ-8) and the monthly attack frequency score. In MwoA, significantly decreased CBF connectivity was detected between ORBmid.R and the left superior frontal gyrus, the right putamen, the right caudate, as well as the right angular gyrus. In addition, increased CBF connectivity was observed between the left calcarine cortex and ORBmid.R.ConclusionsOur results indicate that migraine patients exhibit abnormalities in regional CBF and feature CBF connection defects at the resting state. The affected areas involve information perception, information integration, and emotional, pain and visual processing. Our findings might provide important clues for the pathophysiology of migraine.