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Bao X, Zhang D, Li X, Liu M, Ma H. Long-term high-altitude exposure influences task-related representations in visual working memory. Front Neurol 2023; 14:1149623. [PMID: 37273714 PMCID: PMC10236478 DOI: 10.3389/fneur.2023.1149623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 04/27/2023] [Indexed: 06/06/2023] Open
Abstract
Objective Human working memory is impaired when individuals are exposed to high altitudes, however, whether the capacity of visual working memory is affected remains unclear. This study combined a lateralized change detection task and event-related potentials analysis to explore changes in visual working memory capacity among individuals who emigrated from a low-altitude environment to Tibet (a high-altitude environment). Materials and methods Thirty-five college students were recruited from Tibet University as the high-altitude (HA) group, and thirty-six low-altitude (LA) students were enrolled from South China Normal University (sea level) as the LA group. We measured participants' contralateral delay activity (CDA) under different memory loads. Results ERP component analysis showed that both the HA and LA groups reached an asymptote at memory load four. However, the contralateral and ipsilateral activity of the HA and LA groups shows different patterns. The results showed a significantly larger contralateral activity for the LA group than for the HA group at memory load one (p = 0.04, Cohen's d = 0.52) and load three (p = 0.02, Cohen's d = 0.61). Additionally, we found marginally larger contralateral activity at memory load four for the LA group (p = 0.06, Cohen's d = 0.47), but not at memory load two (p = 0.10) or load five (p = 0.12). No significant differences were observed for ipsilateral activity. In addition, we observed that the HA group performed larger ipsilateral activity than contralateral activity under each memory load, compared with the LA group. Conclusion These findings demonstrated that the attentional resource of long-term HA exposure is more captured by task-irrelevant information, potentially due to impaired inhibitory control, which makes it difficult for them to exclude the interference of task-irrelevant information.
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Affiliation(s)
- Xiaohua Bao
- Faculty of Psychology, Tianjin Normal University, Tianjin, China
| | - Delong Zhang
- Plateau Brain Science Research Center, South China Normal University, Guangzhou, China
- Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China
| | - Xiaoyan Li
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
| | - Ming Liu
- Plateau Brain Science Research Center, South China Normal University, Guangzhou, China
- Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China
| | - Hailin Ma
- Plateau Brain Science Research Center, Tibet University, Lhasa, China
- Academy of Plateau Science and Sustainability, People's Government of Qinghai Province, Xining, China
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Zhang X, Xie W, Liu Y, Li M, Lin J, Yin W, Yang L, Li P, Sun Y, Li T, Liu H, Ma H, Zhang J. Brain Structural and Functional Alterations in Native Tibetans Living at High Altitude. Neuroscience 2023; 520:134-143. [PMID: 36716913 DOI: 10.1016/j.neuroscience.2023.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/30/2023]
Abstract
Tibetans have adapted to high altitude environments. However, the genetic effects in their brains have not been identified. Twenty-five native Tibetans living in Lhasa (3650 m) were recruited for comparison with 20 Han immigrants who originated from lowlands and had been living in Lhasa for two years. The physiological characteristics, brain structure and neuronal spontaneous activity were investigated. Compared with Han immigrants, Tibetans showed higher peripheral oxygen saturation (SpO2), and lower heart rate, red blood cell counts, hematocrit, and hemoglobin. Tibetans showed increased gray matter volume in the visual cortex, hippocampus, and rectus; increased the amplitudes of low-frequency fluctuations (ALFF) values in the left putamen and left fusiform gyrus; and decreased voxel-mirrored homotopic connectivity (VMHC) values in the precentral gyrus. Moreover, Tibetans have decreased functional connectivity (FC) between the left precentral gyrus and the frontal gyrusand right precuneus. In Tibetans and Han immigrants, hemoglobin and hematocrit were negatively correlated with total gray matter volume in males, SpO2 was also positively correlated with ALFF in the left fusiform gyrus, while hemoglobin, and hematocrit were positively correlated with VMHC in the precentral gyrus and FC in the precentral gyrus with other brain regions, SpO2 was also found to be negatively correlated with VMHC in the precentral gyrus, and hemoglobin and hematocrit were negatively correlated with ALFF in the left putamen and left fusiform gyrus. In summary, genetic mutations may result in modulation of some brain regions, which was further confirmed by the identification of correlations with hemoglobin and hematocrit in these regions.
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Affiliation(s)
- Xinjuan Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Weiwei Xie
- Plateau Brain Science Research Centre, Tibet University, Lhasa 850012, China
| | - Yanqiu Liu
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Minglu Li
- Department of Clinical Medicine, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Jianzhong Lin
- Department of Radiology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361102, China
| | - Wu Yin
- Department of Radiology, Tibet Autonomous Region People's Hospital, Lhasa 850000, Tibet Autonomous Region, China
| | - Lihui Yang
- Department of Endocrinology, Tibet Autonomous Region People's Hospital, Lhasa 850000, Tibet Autonomous Region, China
| | - Pengji Li
- Plateau Brain Science Research Centre, Tibet University, Lhasa 850012, China
| | - Ying Sun
- Plateau Brain Science Research Centre, Tibet University, Lhasa 850012, China
| | - Tianzhi Li
- Plateau Brain Science Research Centre, Tibet University, Lhasa 850012, China
| | - Haipeng Liu
- Department of Radiology, Tibet Autonomous Region Women's and Children's Hospital, Lhasa 850000, Tibet Autonomous Region, China
| | - Hailin Ma
- Plateau Brain Science Research Centre, Tibet University, Lhasa 850012, China.
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China.
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3
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Zhang X, Xie W, Du W, Liu Y, Lin J, Yin W, Yang L, Yuan F, Zhang R, Liu H, Ma H, Zhang J. Consistent differences in brain structure and functional connectivity in high-altitude native Tibetans and immigrants. Brain Imaging Behav 2023; 17:271-281. [PMID: 36694086 DOI: 10.1007/s11682-023-00759-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 12/13/2022] [Accepted: 01/17/2023] [Indexed: 01/26/2023]
Abstract
It has been well-established that high-altitude (HA) environments affect the human brain; however, the differences in brain structural and functional networks between HA natives and acclimatized immigrants have not been well clarified. In this study, native HA Tibetans were recruited for comparison with Han immigrants (average of 2.3 ± 0.3 years at HA), with lowland residents recruited as controls. Cortical gray matter volume, thickness, and functional connectivity were investigated using magnetic resonance imaging data. In addition, reaction time and correct score in the visual movement task, hematology, and SpO2 were measured. In both Tibetans and HA immigrants vs. lowlanders, decreased SpO2, increased hematocrit and hemoglobin, and increased reaction time and correct score in the visual movement task were detected. In both Tibetans and HA immigrants vs. lowlanders, gray matter volumes and cortical thickness were increased in the left somatosensory and motor cortex, and functional connectivity was decreased in the visual, default mode, subcortical, somatosensory-motor, ventral attention, and subcortical networks. Furthermore, SpO2 increased, hematocrit and hemoglobin decreased, and gray matter volumes and cortical thickness increased in the visual cortex, left motor cortex, and right auditory cortex in native Tibetans compared to immigrants. Movement time and correct score in task were positively correlated with the thickness of the visual cortex. In conclusion, brain structural and functional network difference in both Tibetan natives and HA immigrants were largely consistent, with native Tibetans only showing more intense brain modulation. Different populations acclimatized to HA develop similar brain mechanisms to cope with hostile HA environmental factors.
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Affiliation(s)
- Xinjuan Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Weiwei Xie
- Plateau Brain Science Research Centre, Tibet University, Lhasa, 850012, China
| | - Wenrui Du
- Department of Clinical Medicine, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Yanqiu Liu
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Jianzhong Lin
- Department of Radiology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Wu Yin
- Department of Radiology, Tibet Autonomous Region People's Hospital, Lhasa, Tibet Autonomous Region, 850000, China
| | - Lihui Yang
- Department of Endocrinology, Tibet Autonomous Region People's Hospital, Tibet Autonomous Region, Lhasa, 850000, China
| | - Fengjuan Yuan
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Ran Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Haipeng Liu
- Department of Radiology, Tibet Autonomous Region Women's and Children's Hospital, Tibet Autonomous Region, Lhasa, 850000, China
| | - Hailin Ma
- Plateau Brain Science Research Centre, Tibet University, Lhasa, 850012, China.
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, 361102, China.
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Vedaei F, Alizadeh M, Tantawi M, Romo V, Mohamed FB, Wu C. Vascular and neuronal effects of general anesthesia on the brain: An fMRI study. J Neuroimaging 2023; 33:109-120. [PMID: 36097249 DOI: 10.1111/jon.13049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/30/2022] [Accepted: 08/30/2022] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND AND PURPOSE A number of functional magnetic resonance imaging (fMRI) studies rely on application of anesthetic agents during scanning that can modulate and complicate interpretation of the measured hemodynamic blood oxygenation level-dependent (BOLD) response. The purpose of the present study was to investigate the effect of general anesthesia on two main components of BOLD signal including neuronal activity and vascular response. METHODS Breath-holding (BH) fMRI was conducted in wakefulness and under anesthesia states in 9 patients with drug-resistant epilepsy who needed to get scanned under anesthesia during laser interstitial thermal therapy. BOLD and BOLD cerebrovascular reactivity (BOLD-CVR) maps were compared using t-test between two states to assess the effect of anesthesia on neuronal activity and vascular factors (p < .05). RESULTS Overall, our findings revealed an increase in BOLD-CVR and decrease in BOLD response under anesthesia in several brain regions. The results proposed that the modulatory mechanism of anesthetics on neuronal and vascular components of BOLD signal may work in different ways. CONCLUSION This experiment for the first human study showed that anesthesia may play an important role in dissociation between neuronal and vascular responses contributed to hemodynamic BOLD signal using BH fMRI imaging that may assist the implication of general anesthesia and interpretation of outcomes in clinical setting.
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Affiliation(s)
- Faezeh Vedaei
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mahdi Alizadeh
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mohamed Tantawi
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Victor Romo
- Department of Anesthesiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Feroze B Mohamed
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Chengyuan Wu
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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5
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Zhang X, Zhang J. The human brain in a high altitude natural environment: A review. Front Hum Neurosci 2022; 16:915995. [PMID: 36188182 PMCID: PMC9520777 DOI: 10.3389/fnhum.2022.915995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/25/2022] [Indexed: 12/04/2022] Open
Abstract
With the advancement of in vivo magnetic resonance imaging (MRI) technique, more detailed information about the human brain at high altitude (HA) has been revealed. The present review aimed to draw a conclusion regarding changes in the human brain in both unacclimatized and acclimatized states in a natural HA environment. Using multiple advanced analysis methods that based on MRI as well as electroencephalography, the modulations of brain gray and white matter morphology and the electrophysiological mechanisms underlying processing of cognitive activity have been explored in certain extent. The visual, motor and insular cortices are brain regions seen to be consistently affected in both HA immigrants and natives. Current findings regarding cortical electrophysiological and blood dynamic signals may be related to cardiovascular and respiratory regulations, and may clarify the mechanisms underlying some behaviors at HA. In general, in the past 10 years, researches on the brain at HA have gone beyond cognitive tests. Due to the sample size is not large enough, the current findings in HA brain are not very reliable, and thus much more researches are needed. Moreover, the histological and genetic bases of brain structures at HA are also needed to be elucidated.
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Affiliation(s)
- Xinjuan Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, China
- Department of Physiology, School of Medicine, Xiamen University, Xiamen, China
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen, China
- Department of Physiology, School of Medicine, Xiamen University, Xiamen, China
- *Correspondence: Jiaxing Zhang,
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6
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Resting-State Neuronal Activity and Functional Connectivity Changes in the Visual Cortex after High Altitude Exposure: A Longitudinal Study. Brain Sci 2022; 12:brainsci12060724. [PMID: 35741609 PMCID: PMC9221383 DOI: 10.3390/brainsci12060724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 12/31/2022] Open
Abstract
Damage to the visual cortex structures after high altitude exposure has been well clarified. However, changes in the neuronal activity and functional connectivity (FC) of the visual cortex after hypoxia/reoxygenation remain unclear. Twenty-three sea-level college students, who took part in 30 days of teaching at high altitude (4300 m), underwent routine blood tests, visual behavior tests, and magnetic resonance imaging scans before they went to high altitude (Test 1), 7 days after they returned to sea level (Test 2), as well as 3 months (Test 3) after they returned to sea level. In this study, we investigated the hematological parameters, behavioral data, and spontaneous brain activity. There were significant differences among the tests in hematological parameters and spontaneous brain activity. The hematocrit, hemoglobin concentration, and red blood cell count were significantly increased in Test 2 as compared with Tests 1 and 3. As compared with Test 1, Test 3 increased amplitudes of low-frequency fluctuations (ALFF) in the right calcarine gyrus; Tests 2 and 3 increased ALFF in the right supplementary motor cortex, increased regional homogeneity (ReHo) in the left lingual gyrus, increased the voxel-mirrored homotopic connectivity (VMHC) value in the motor cortex, and decreased FC between the left lingual gyrus and left postcentral gyrus. The color accuracy in the visual task was positively correlated with ALFF and ReHo in Test 2. Hypoxia/reoxygenation increased functional connection between the neurons within the visual cortex and the motor cortex but decreased connection between the visual cortex and motor cortex.
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7
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Pinto J, Bright MG, Bulte DP, Figueiredo P. Cerebrovascular Reactivity Mapping Without Gas Challenges: A Methodological Guide. Front Physiol 2021; 11:608475. [PMID: 33536935 PMCID: PMC7848198 DOI: 10.3389/fphys.2020.608475] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/02/2020] [Indexed: 01/08/2023] Open
Abstract
Cerebrovascular reactivity (CVR) is defined as the ability of vessels to alter their caliber in response to vasoactive factors, by means of dilating or constricting, in order to increase or decrease regional cerebral blood flow (CBF). Importantly, CVR may provide a sensitive biomarker for pathologies where vasculature is compromised. Furthermore, the spatiotemporal dynamics of CVR observed in healthy subjects, reflecting regional differences in cerebral vascular tone and response, may also be important in functional MRI studies based on neurovascular coupling mechanisms. Assessment of CVR is usually based on the use of a vasoactive stimulus combined with a CBF measurement technique. Although transcranial Doppler ultrasound has been frequently used to obtain global flow velocity measurements, MRI techniques are being increasingly employed for obtaining CBF maps. For the vasoactive stimulus, vasodilatory hypercapnia is usually induced through the manipulation of respiratory gases, including the inhalation of increased concentrations of carbon dioxide. However, most of these methods require an additional apparatus and complex setups, which not only may not be well-tolerated by some populations but are also not widely available. For these reasons, strategies based on voluntary breathing fluctuations without the need for external gas challenges have been proposed. These include the task-based methodologies of breath holding and paced deep breathing, as well as a new generation of methods based on spontaneous breathing fluctuations during resting-state. Despite the multitude of alternatives to gas challenges, existing literature lacks definitive conclusions regarding the best practices for the vasoactive modulation and associated analysis protocols. In this work, we perform an extensive review of CVR mapping techniques based on MRI and CO2 variations without gas challenges, focusing on the methodological aspects of the breathing protocols and corresponding data analysis. Finally, we outline a set of practical guidelines based on generally accepted practices and available data, extending previous reports and encouraging the wider application of CVR mapping methodologies in both clinical and academic MRI settings.
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Affiliation(s)
- Joana Pinto
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
- Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Molly G. Bright
- Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
- Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, United States
| | - Daniel P. Bulte
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Patrícia Figueiredo
- Institute for Systems and Robotics - Lisboa and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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8
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Li S, Lv P, He M, Zhang W, Liu J, Gong Y, Wang T, Gong Q, Ji Y, Lui S. Cerebral regional and network characteristics in asthma patients: a resting-state fMRI study. Front Med 2020; 14:792-801. [PMID: 32270434 DOI: 10.1007/s11684-020-0745-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/18/2019] [Indexed: 02/08/2023]
Abstract
Asthma is a serious health problem that involves not only the respiratory system but also the central nervous system. Previous studies identified either regional or network alterations in patients with asthma, but inconsistent results were obtained. A key question remains unclear: are the regional and neural network deficits related or are they two independent characteristics in asthma? Answering this question is the aim of this study. By collecting resting-state functional magnetic resonance imaging from 39 patients with asthma and 40 matched health controls, brain functional measures including regional activity (amplitude of low-frequency fluctuations) and neural network function (degree centrality (DC) and functional connectivity) were calculated to systematically characterize the functional alterations. Patients exhibited regional abnormities in the left angular gyrus, right precuneus, and inferior temporal gyrus within the default mode network. Network abnormalities involved both the sensorimotor network and visual network with key regions including the superior frontal gyrus and occipital lobes. Altered DC in the lingual gyrus was correlated with the degree of airway obstruction. This study elucidated different patterns of regional and network changes, thereby suggesting that the two parameters reflect different brain characteristics of asthma. These findings provide evidence for further understanding the potential cerebral alterations in the pathophysiology of asthma.
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Affiliation(s)
- Siyi Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Peilin Lv
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Min He
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Wenjing Zhang
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Jieke Liu
- Department of Radiology, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610041, China
| | - Yao Gong
- Department of Geriatric Psychiatry, The Fourth People's Hospital of Chengdu, Chengdu, 610036, China
| | - Ting Wang
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China
| | - Yulin Ji
- Department of Respiratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Su Lui
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, China.
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9
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Ma H, Zhang D, Li X, Ma H, Wang N, Wang Y. Long-term exposure to high altitude attenuates verbal and spatial working memory: Evidence from an event-related potential study. Brain Behav 2019; 9:e01256. [PMID: 30891949 PMCID: PMC6456776 DOI: 10.1002/brb3.1256] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 01/22/2019] [Accepted: 02/12/2019] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION This study aimed to determine the neurocognitive basis underlying the effects of long-term high-altitude (HA) exposure on working memory (WM). METHODS Using event-related potentials (ERPs), we compared the performance of an HA group (individuals who had lived at HA for 3 years but were born and raised at low altitude [LA]) to that of an LA group (individuals who had only lived at LA) on verbal and spatial n-back tasks (i.e., 1- and 2-back memory load). RESULTS Response accuracy of the HA group was significantly decreased in comparison to the LA group in both the verbal and spatial 2-back tasks. The P2 amplitude was larger in the HA than in the LA group in the spatial, but not the verbal 2-back task. A smaller late-positive potential (LPP) amplitude was found in the HA group in both the verbal and spatial 2-back tasks. CONCLUSIONS These results suggest that HA impairs the matching (P2) process in spatial WM tasks and the maintenance (LPP) process in both verbal and spatial WM tasks, indicating that HA had a different effect on verbal and spatial 2-back task performance.
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Affiliation(s)
- Hailin Ma
- Center on Aging PsychologyCAS Key Laboratory of Mental HealthInstitute of PsychologyBeijingChina
- Plateau Brain Science Research CenterTibet University/South China Normal UniversityGuangzhou/TibetChina
| | - Delong Zhang
- Plateau Brain Science Research CenterTibet University/South China Normal UniversityGuangzhou/TibetChina
- Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of PsychologySouth China Normal UniversityGuangzhouChina
| | - Xuebing Li
- Center on Aging PsychologyCAS Key Laboratory of Mental HealthInstitute of PsychologyBeijingChina
| | - Huifang Ma
- College of ManagementTianjin UniversityTianjinChina
| | - Niannian Wang
- Plateau Brain Science Research CenterTibet University/South China Normal UniversityGuangzhou/TibetChina
| | - Yan Wang
- Center on Aging PsychologyCAS Key Laboratory of Mental HealthInstitute of PsychologyBeijingChina
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10
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Urback AL, Metcalfe AW, Korczak DJ, MacIntosh BJ, Goldstein BI. Reduced cerebrovascular reactivity among adolescents with bipolar disorder. Bipolar Disord 2019; 21:124-131. [PMID: 30422372 DOI: 10.1111/bdi.12719] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Cardiovascular disease (CVD) is excessive and premature among individuals with bipolar disorder (BD). Cerebrovascular reactivity (CVR), reflecting vasodilatory capacity of cerebral blood vessels in response to vasoactive substances, is a marker of cerebrovascular health. Despite informative findings in other diseases, CVR has not previously been examined in BD. METHODS Twenty-five adolescents with BD and 25 age and sex-matched psychiatrically healthy controls (HCs) completed six 15-second breath-holds (BHs) during functional magnetic resonance imaging (fMRI) at 3-Tesla. CVR was determined by comparing blood-oxygenation-level dependent (BOLD) signal changes. Voxel-wise contrasts were analyzed. Body mass index (BMI) was examined as a potential confound. RESULTS CVR in the posterior cingulate gyrus and periventricular white matter was lower in BD vs HC. After controlling for differences in BMI, additional between-group CVR differences were observed in the temporal poles, supramarginal gyrus, and lingual gyrus. There were no regions in which CVR was significantly greater in BD vs HC. CVR was not associated with mood symptoms. CONCLUSIONS This preliminary study provides evidence of cerebrovascular dysfunction in BD, including regions known to be susceptible to cerebrovascular dysfunction and/or disease. These findings warrant additional research on the causes and consequences of cerebrovascular dysfunction in early-onset BD.
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Affiliation(s)
- Adam L Urback
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Arron Ws Metcalfe
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Daphne J Korczak
- Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, Hospital for Sick Children, Toronto, ON, Canada
| | - Bradley J MacIntosh
- Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Benjamin I Goldstein
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Pharmacology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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11
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Alterations of resting-state functional network centrality in patients with asthma: evidence from a voxel-wise degree centrality analysis. Neuroreport 2019; 29:1151-1156. [PMID: 29975256 DOI: 10.1097/wnr.0000000000001087] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Several previous studies have reported that asthma patients have abnormal brain activities, whereas alterations in the resting-state network still remain unknown. The aim of this study was to investigate the changes in functional network centrality in asthma patients using voxel-wise degree centrality (DC) method. Asthma patients and healthy controls (HCs) were matched closely in age, sex, and education of participants. The DC method was used to evaluate the functional network centrality. The receiver operating characteristic curve was used to distinguish the asthma group from the HCs group. The Pearson correlation coefficient was used to explore the relationship between the observed mean values of DC in different brain areas and the behavioral performance. Compared with HCs, DC values were significantly decreased in the right middle temporal gyrus and the right putamen of asthma patients. In contrast, in asthma patients, DC values were markedly increased in the right posterior lobe of the cerebellum, right inferior temporal gyrus, left superior frontal gyrus, left postcentral gyrus and inferior parietal lobule, left middle frontal gyrus, and left postcentral gyrus. However, there was no relationship between the observed mean DC values in different brain areas and the behavioral performance. The results showed that the DC values were altered in various brain regions of asthma patients, which were related to default mode network, the cortex-basal ganglia network, the frontoparietal network, and the sensorimotor network, leading to some useful information for clinical studies in asthma patients.
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Urback AL, Metcalfe AWS, Korczak DJ, MacIntosh BJ, Goldstein BI. Magnetic resonance imaging of cerebrovascular reactivity in healthy adolescents. J Neurosci Methods 2018; 306:1-9. [PMID: 29879447 DOI: 10.1016/j.jneumeth.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/24/2018] [Accepted: 06/02/2018] [Indexed: 10/14/2022]
Abstract
BACKGROUND Cerebrovascular reactivity (CVR), an important measure of cerebrovascular health in adults, has not been examined in healthy adolescents. Beyond the direct importance of understanding CVR in healthy youth, studies on this topic can yield insights regarding brain disease. We set out to evaluate 3 different CVR modelling approaches. NEW METHOD Thirty-nine healthy adolescents (ages 13-19 years, 20 females) completed six blocks of 15-second breath-holds separated by 30-second blocks of free-breathing. CVR was measured using blood-oxygenation-level dependent functional magnetic resonance imaging at 3-Tesla; voxel-wise analyses were complemented by regional analyses in five major subdivisions of the brain. Hemodynamic response functions were modelled using: (1) an individualized delay term (double-gamma variate convolved with a boxcar function), (2) with a standard 9-second delay term, and (3) a sine-cosine regressor. RESULTS Individual-delay yielded superior model fit or larger cluster volumes. Regional analysis found differences in CVR and time-to-peak CVR. Males had higher brain-wide CVR in comparison to females (p = 0.025, η2part = 0.345). BMI and blood pressure were not significantly associated with CVR (all p > 0.4). COMPARISON WITH EXISTING METHODS This was the first study to compare these methods in youth. Regional differences were similar to adult studies. CONCLUSIONS These findings lend support to future breath-hold CVR studies in youth, and highlight the merit of applying individualized-delay estimates. Regional variability and sex-related differences in CVR suggest that these variables should be considered in future studies, particularly those that examine disease states with predilection for specific brain regions or those diseases characterized by sex differences.
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Affiliation(s)
- Adam L Urback
- Department of Psychiatry, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Arron W S Metcalfe
- Department of Psychiatry, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room M6 180, Toronto, ON, M4N 3M5, Canada.
| | - Daphne J Korczak
- Department of Psychiatry, University of Toronto, Medicine, 250 College Street, Room 835, Toronto, ON, M5T 1R8, Canada; Department of Psychiatry, Hospital For Sick Children, 555 University Avenue, Room 1145, Elm Wing, Toronto, ON, M5G 1X8, Canada.
| | - Bradley J MacIntosh
- Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room M6 180, Toronto, ON, M4N 3M5, Canada; University of Toronto, Department of Medical Biophysics, 101 College Street Suite 15-701, Toronto, ON, M5G 1L7, Canada.
| | - Benjamin I Goldstein
- Department of Psychiatry, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada; Department of Psychiatry, University of Toronto, Medicine, 250 College Street, Room 835, Toronto, ON, M5T 1R8, Canada.
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13
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Wang X, Wei W, Yuan F, Li S, Lin J, Zhang J. Regional cerebral blood flow in natives at high altitude: An arterial spin labeled MRI study. J Magn Reson Imaging 2018; 48:708-717. [PMID: 29493838 DOI: 10.1002/jmri.25996] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Accepted: 02/13/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It is known that a neurologic sequence occurs at high altitudes (HA); hence, cerebral blood flow (CBF) might vary by altitude. PURPOSE To use arterial spin labeled (ASL) MRI to evaluate absolute CBF differences between subjects who live at HA and lowlands. STUDY TYPE Cohort prospective trial. POPULATION In all, 64 HA Tibetans, 19 lowland Tibetans, and 25 lowland Han subjects. FIELD STRENGTH/SEQUENCE CBF was measured with the pulsed ASL sequence at 3T. ASSESSMENT CBF was correlated with abode altitude in HA Tibetans; CBF differences among HA Tibetans, lowland Tibetans, and lowland Han subjects was assessed. STATISTICAL TESTS Pearson correlation assessed the correlation. Independent t-tests analyzed group differences. RESULTS In HA Tibetans, CBF decreased with altitude in the bilateral anterior and posterior cingulate gyri, fusiform gyrus, cerebellar tonsil and cortices, and thalamus as well as left middle and inferior temporal gyri and right insula (P < 0.05); HA Tibetans (vs. lowland Tibetans) had lower CBF in the left hemisphere (precuneus, anterior cingulate gyrus, fusiform gyrus, and lingual gyrus) and right hemisphere (superior parietal lobule, precuneus, posterior cingulate gyrus, and cerebellar tonsil), while they had higher CBF in the left inferior parietal lobule, lentiform nucleus, and inferior frontal gyrus (P < 0.05). The overlapping regions, in which CBF in HA Tibetans correlated with altitude and decreased (vs. lowland Tibetans), were selected for region of interest analysis, and the results showed lower CBF in HA Tibetans than lowland Han subjects (P < 0.05). DATA CONCLUSION HA adaptation in Tibetans is associated with a decrease of regional CBF. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018.
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Affiliation(s)
- Xiaochuan Wang
- Department of Neurology, Affiliated Hospital of Hangzhou Normal University, Hangzhou, China
| | - Wenping Wei
- MRI Center, First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Fengjuan Yuan
- Institute of Brain Diseases and Cognition, Medical College of Xiamen University, Xiamen, China
| | - Shanhua Li
- Institute of Brain Diseases and Cognition, Medical College of Xiamen University, Xiamen, China
| | - Jianzhong Lin
- Magnetic Resonance Center, Zhongshan Hospital Xiamen University, Xiamen, China
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, Medical College of Xiamen University, Xiamen, China
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, China
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Ozturk ED, Tan CO. Human cerebrovascular function in health and disease: insights from integrative approaches. J Physiol Anthropol 2018; 37:4. [PMID: 29454381 PMCID: PMC5816507 DOI: 10.1186/s40101-018-0164-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/02/2018] [Indexed: 11/21/2022] Open
Abstract
Background The marked increase in the size of the brain, and consequently, in neural processing capability, throughout human evolution is the basis of the higher cognitive function in humans. However, greater neural, and thus information processing capability, comes at a significant metabolic cost; despite its relatively small size, the modern human brain consumes almost a quarter of the glucose and oxygen supply in the human body. Fortunately, several vascular mechanisms ensure sufficient delivery of glucose and oxygen to the active neural tissue (neurovascular coupling), prompt removal of neural metabolic by-products (cerebral vasoreactivity), and constant global blood supply despite daily variations in perfusion pressure (cerebral autoregulation). The aim of this review is to provide an integrated overview of the available data on these vascular mechanisms and their underlying physiology. We also briefly review modern experimental approaches to assess these mechanisms in humans, and further highlight the importance of these mechanisms for humans’ evolutionary success by providing examples of their healthy adaptations as well as pathophysiological alterations. Conclusions Data reviewed in this paper demonstrate the importance of the cerebrovascular function to support humans’ unique ability to form new and different interactions with each other and their surroundings. This highlights that there is much insight into the neural and cognitive functions that could be gleaned from interrogating the cerebrovascular function.
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Affiliation(s)
- Erin D Ozturk
- Cerebrovascular Research Laboratory, Spaulding Rehabilitation Hospital, Boston, MA, USA.,Department of Psychology, Harvard University, Cambridge, MA, USA
| | - Can Ozan Tan
- Cerebrovascular Research Laboratory, Spaulding Rehabilitation Hospital, Boston, MA, USA. .,Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA, USA.
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15
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Wong E, Yang B, Du L, Ho WH, Lau C, Ke Y, Chan YS, Yung WH, Wu EX. The multi-level impact of chronic intermittent hypoxia on central auditory processing. Neuroimage 2017; 156:232-239. [PMID: 28528846 DOI: 10.1016/j.neuroimage.2017.05.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 04/07/2017] [Accepted: 05/16/2017] [Indexed: 12/21/2022] Open
Abstract
During hypoxia, the tissues do not obtain adequate oxygen. Chronic hypoxia can lead to many health problems. A relatively common cause of chronic hypoxia is sleep apnea. Sleep apnea is a sleep breathing disorder that affects 3-7% of the population. During sleep, the patient's breathing starts and stops. This can lead to hypertension, attention deficits, and hearing disorders. In this study, we apply an established chronic intermittent hypoxemia (CIH) model of sleep apnea to study its impact on auditory processing. Adult rats were reared for seven days during sleeping hours in a gas chamber with oxygen level cycled between 10% and 21% (normal atmosphere) every 90s. During awake hours, the subjects were housed in standard conditions with normal atmosphere. CIH treatment significantly reduces arterial oxygen partial pressure and oxygen saturation during sleeping hours (relative to controls). After treatment, subjects underwent functional magnetic resonance imaging (fMRI) with broadband sound stimulation. Responses are observed in major auditory centers in all subjects, including the auditory cortex (AC) and auditory midbrain. fMRI signals from the AC are statistically significantly increased after CIH by 0.13% in the contralateral hemisphere and 0.10% in the ipsilateral hemisphere. In contrast, signals from the lateral lemniscus of the midbrain are significantly reduced by 0.39%. Signals from the neighboring inferior colliculus of the midbrain are relatively unaffected. Chronic hypoxia affects multiple levels of the auditory system and these changes are likely related to hearing disorders associated with sleep apnea.
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Affiliation(s)
- Eddie Wong
- Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Bin Yang
- Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Department of Radiology, Children's Hospital of Fudan University, Shanghai, People's Republic of China
| | - Lida Du
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Gerald Choa Neuroscience Centre, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Wai Hong Ho
- Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Condon Lau
- Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.
| | - Ya Ke
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Gerald Choa Neuroscience Centre, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Ying Shing Chan
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Wing Ho Yung
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Gerald Choa Neuroscience Centre, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
| | - Ed X Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China; Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China
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16
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Urback AL, MacIntosh BJ, Goldstein BI. Cerebrovascular reactivity measured by functional magnetic resonance imaging during breath-hold challenge: A systematic review. Neurosci Biobehav Rev 2017; 79:27-47. [PMID: 28487157 DOI: 10.1016/j.neubiorev.2017.05.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 04/05/2017] [Accepted: 05/02/2017] [Indexed: 10/19/2022]
Abstract
Cerebrovascular reactivity (CVR) is the cerebral hemodynamic response to a vasoactive substance. Breath-hold (BH) induced CVR has the advantage of being non-invasive and easy to implement during magnetic resonance imaging (MRI). We systematically reviewed the literature regarding MRI measurement of BH induced CVR. The literature was searched using MEDLINE with the search terms breath-hold; and MRI or cerebrovascular reactivity. The search yielded 2244 results and 54 articles were included. Between-group comparisons have found that CVR was higher among healthy controls than patients with various pathologies (e.g. sleep apnea, diabetes, hypertension etc.). However, counter-intuitive findings have also been reported, including higher CVR among smokers, sedentary individuals, and patients with schizophrenia vs. CONTROLS Methodological studies have highlighted important measurement characteristics (e.g. normalizing signal to end-tidal CO2), and comparisons of BH induced CVR to non-BH methods. Future studies are warranted to address questions about group differences, treatment response, disease progression, and other salient clinical themes. Standardization of CVR and BH designs is needed to fully exploit the potential of this practical non-invasive method.
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Affiliation(s)
- Adam L Urback
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Bradley J MacIntosh
- University of Toronto, Department of Medical Biophysics, 101 College Street Suite 15-701, Toronto, ON, M5G 1L7, Canada; Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre, 2075 Bayview Ave., Room M6 180, Toronto, ON, M4N 3M5, Canada.
| | - Benjamin I Goldstein
- Centre for Youth Bipolar Disorder, Sunnybrook Health Sciences Centre 2075 Bayview Ave., FG-53, Toronto, ON, M4N 3M5, Canada; Department of Pharmacology, University of Toronto, Medicine, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada; Department of Psychiatry, University of Toronto, Medicine,250 College Street, Room 835, Toronto, ON, M5T 1R8, Canada.
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17
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Zhang J, Chen J, Fan C, Li J, Lin J, Yang T, Fan M. Alteration of Spontaneous Brain Activity After Hypoxia-Reoxygenation: A Resting-State fMRI Study. High Alt Med Biol 2017; 18:20-26. [PMID: 28266873 DOI: 10.1089/ham.2016.0083] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Zhang, Jiaxing, Ji Chen, Cunxiu Fan, Jinqiang Li, Jianzhong Lin, Tianhe Yang, and Ming Fan. Alteration of spontaneous brain activity after hypoxia-reoxygenation: A resting-state fMRI study. High Alt Med Biol. 18:20-26, 2017.-The present study was designed to investigate the effect of hypoxia-reoxygenation on the spontaneous neuronal activity in brain. Sixteen sea-level (SL) soldiers (20.5 ± 0.7 years), who garrisoned the frontiers in high altitude (HA) (2300-4400 m) for two years and subsequently descended to sea level for one to seven days, were recruited. Control group consisted of 16 matched SL natives. The amplitude of low-frequency fluctuations (ALFF) of regional brain functional magnetic resonance imaging signal in resting state and functional connectivity (FC) between brain regions was analyzed. HA subjects showed significant increases of ALFF at several sites within the bilateral occipital cortices and significant decreases of ALFF in the right anterior insula and extending to the caudate, putamen, inferior frontal orbital cortex, temporal pole, and superior temporal gyrus; lower ALFF values in the right insula were positively correlated with low respiratory measurements. The right insula in HA subjects had increases of FC with the right superior temporal gyrus, postcentral gyrus, rolandic operculum, supramarginal gyrus, and inferior frontal triangular area. We thus demonstrated that hypoxia-reoxygenation had influence on the spontaneous neuronal activity in brain. The decrease of insular neuronal activity may be related to the reduction of ventilatory drive, while the increase of FC with insula may indicate a central compensation.
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Affiliation(s)
- Jiaxing Zhang
- 1 Department of Physiology, Medical College of Xiamen University , Xiamen, China
| | - Ji Chen
- 1 Department of Physiology, Medical College of Xiamen University , Xiamen, China
| | - Cunxiu Fan
- 1 Department of Physiology, Medical College of Xiamen University , Xiamen, China
| | - Jinqiang Li
- 2 Department of Clinical Psychology, Gulangyu Sanatorium of PLA , Xiamen, China
| | - Jianzhong Lin
- 3 Magnetic Resonance Center, Zhongshan Hospital Xiamen University , Xiamen, China
| | - Tianhe Yang
- 3 Magnetic Resonance Center, Zhongshan Hospital Xiamen University , Xiamen, China
| | - Ming Fan
- 4 Department of Cognitive Sciences, Institute of Basic Medical Sciences , Beijing, China
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18
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Wei W, Wang X, Gong Q, Fan M, Zhang J. Cortical Thickness of Native Tibetans in the Qinghai-Tibetan Plateau. AJNR Am J Neuroradiol 2017; 38:553-560. [PMID: 28104637 DOI: 10.3174/ajnr.a5050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/24/2016] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND PURPOSE High-altitude environmental factors and genetic variants together could have exerted their effects on the human brain. The present study was designed to investigate the cerebral morphology in high-altitude native Tibetans. MATERIALS AND METHODS T1-weighted brain images were obtained from 77 Tibetan adolescents on the Qinghai-Tibetan Plateau (altitude, 2300-5300 m) and 80 matched Han controls living at sea level. Cortical thickness, curvature, and sulcus were analyzed by using FreeSurfer. RESULTS Cortical thickness was significantly decreased in the left posterior cingulate cortex, lingual gyrus, superior parietal cortex, precuneus, and rostral middle frontal cortex and the right medial orbitofrontal cortex, lateral occipital cortex, precuneus, and paracentral lobule. Curvature was significantly decreased in the left superior parietal cortex and right superior marginal gyrus; the depth of the sulcus was significantly increased in the left inferior temporal gyrus and significantly decreased in the right superior marginal gyrus, superior temporal gyrus, and insular cortex. Moreover, cortical thickness was negatively correlated with altitude in the left superior and middle temporal gyri, rostral middle frontal cortex, insular cortex, posterior cingulate cortex, precuneus, lingual gyrus, and the right superior temporal gyrus. Curvature was positively correlated with altitude in the left rostral middle frontal cortex, insular cortex, and middle temporal gyrus. The depth of the sulcus was negatively correlated with altitude in the left lingual gyrus and right medial orbitofrontal cortex. CONCLUSIONS Differences in cortical morphometry in native Tibetans may reflect adaptations related to high altitude.
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Affiliation(s)
- W Wei
- From the MRI Center (W.W.), First Affiliated Hospital of Xiamen University, Xiamen, China.,Institute of Brain Disease and Cognition (W.W., J.Z.), Medical College of Xiamen University, Xiamen, China
| | - X Wang
- Department of Neurology (X.W.), Affiliated Hospital of Hangzhou Normal University, Hangzhou, China
| | - Q Gong
- Huaxi Magnetic Resonance Research Center (Q.G.), West China Hospital, Sichuan University, Chengdu, China
| | - M Fan
- Department of Cognitive Sciences (M.F.), Institute of Basic Medical Sciences, Beijing, China
| | - J Zhang
- Institute of Brain Disease and Cognition (W.W., J.Z.), Medical College of Xiamen University, Xiamen, China
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Characteristics of EEG activity during high altitude hypoxia and lowland reoxygenation. Brain Res 2016; 1648:243-249. [DOI: 10.1016/j.brainres.2016.07.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/12/2016] [Accepted: 07/12/2016] [Indexed: 11/20/2022]
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20
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Leung J, Duffin J, Fisher JA, Kassner A. MRI-based cerebrovascular reactivity using transfer function analysis reveals temporal group differences between patients with sickle cell disease and healthy controls. Neuroimage Clin 2016; 12:624-630. [PMID: 27722086 PMCID: PMC5048082 DOI: 10.1016/j.nicl.2016.09.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 10/26/2022]
Abstract
OBJECTIVES Cerebrovascular reactivity (CVR) measures the ability of cerebral blood vessels to change their diameter and, hence, their capacity to regulate regional blood flow in the brain. High resolution quantitative maps of CVR can be produced using blood-oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) in combination with a carbon dioxide stimulus, and these maps have become a useful tool in the clinical evaluation of cerebrovascular disorders. However, conventional CVR analysis does not fully characterize the BOLD response to a stimulus as certain regions of the brain are slower to react to the stimulus than others, especially in disease. Transfer function analysis (TFA) is an alternative technique that can account for dynamic temporal relations between signals and has recently been adapted for CVR computation. We investigated the application of TFA in data on children with sickle cell disease (SCD) and healthy controls, and compared them to results derived from conventional CVR analysis. MATERIALS AND METHODS Data from 62 pediatric patients with SCD and 34 age-matched healthy controls were processed using conventional CVR analysis and TFA. BOLD data were acquired on a 3 Tesla MRI scanner while a carbon dioxide stimulus was quantified by sampling the end-tidal partial pressures of each exhaled breath. In addition, T1 weighted structural imaging was performed to identify grey and white matter regions for analysis. The TFA method generated maps representing both the relative magnitude change of the BOLD signal in response to the stimulus (Gain), as well as the BOLD signal speed of response (Phase) for each subject. These were compared to CVR maps calculated from conventional analysis. The effect of applying TFA on data from SCD patients versus controls was also examined. RESULTS The Gain measures derived from TFA were significantly higher than CVR values based on conventional analysis in both SCD patients and healthy controls, but the difference was greater in the SCD data. Moreover, while these differences were uniform across the grey and white matter regions of controls, they were greater in white matter than grey matter in the SCD group. Phase was also shown to be significantly correlated with the amount that TFA increases CVR estimates in both the grey and white matter. CONCLUSIONS We demonstrated that conventional CVR analysis underestimates vessel reactivity and this effect is more prominent in patients with SCD. By using TFA, the resulting Gain and Phase measures more accurately characterize the BOLD response as it accounts for the temporal dynamics responsible for the CVR underestimation. We suggest that the additional information offered through TFA can provide insight into the mechanisms underlying CVR compromise in cerebrovascular diseases.
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Affiliation(s)
- Jackie Leung
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - James Duffin
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Joseph A. Fisher
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Andrea Kassner
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada
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Chen J, Fan C, Li J, Han Q, Lin J, Yang T, Zhang J. Increased Intraregional Synchronized Neural Activity in Adult Brain After Prolonged Adaptation to High-Altitude Hypoxia: A Resting-State fMRI Study. High Alt Med Biol 2016; 17:16-24. [PMID: 26906285 DOI: 10.1089/ham.2015.0104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The human brain is intrinsically plastic such that its functional architecture can be reorganized in response to environmental pressures and physiological changes. However, it remains unclear whether a compensatory modification of spontaneous neural activity occurs in adult brain during prolonged high-altitude (HA) adaptation. In this study, we obtained resting-state functional magnetic resonance (MR) images in 16 adults who have immigrated to Qinghai-Tibet Plateau (2300-4400 m) for 2 years and in 16 age-matched sea level (SL) controls. A validated regional homogeneity (Reho) method was employed to investigate the local synchronization of resting-state functional magnetic resonance imaging (fMRI) signals. Seed connectivity analysis was carried out subsequently. Cognitive and physiological assessments were made and correlated with the image metrics. Compared with SL controls, global mean Reho was significantly increased in HA immigrants as well as a regional increase in the right inferolateral sensorimotor cortex. Furthermore, mean z-Reho value extracted within the inferolateral sensorimotor area showed trend-level significant inverse correlation with memory search reaction time in HA immigrants. These observations, for the first time, provide evidence of adult brain resilience of spontaneous neural activity after long-term HA exposure without inherited and developmental effects. Resting-state fMRI could yield valuable information for central mechanisms underlying respiratory and cognitive compensations in adults during prolonged environmentally hypoxic adaptation, paving the way for future HA-adaptive training.
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Affiliation(s)
- Ji Chen
- 1 Department of Physiology and Neurobiology, Medical College of Xiamen University , Xiamen, Fujian, China .,2 Department of Medical Imaging Center, Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA , Fuzhou, Fujian, China
| | - Cunxiu Fan
- 1 Department of Physiology and Neurobiology, Medical College of Xiamen University , Xiamen, Fujian, China
| | - Jinqiang Li
- 3 Department of Clinical Psychology, Gulangyu Sanatorium of PLA , Xiamen, Fujian, China
| | - Qiaoqing Han
- 3 Department of Clinical Psychology, Gulangyu Sanatorium of PLA , Xiamen, Fujian, China
| | - Jianzhong Lin
- 4 Magnetic Resonance Center, Zhongshan Hospital, Medical College of Xiamen University , Xiamen, Fujian, China
| | - Tianhe Yang
- 4 Magnetic Resonance Center, Zhongshan Hospital, Medical College of Xiamen University , Xiamen, Fujian, China
| | - Jiaxing Zhang
- 1 Department of Physiology and Neurobiology, Medical College of Xiamen University , Xiamen, Fujian, China
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Affiliation(s)
- Fabiola León-Velarde
- Departamentao de Ciencias Biologicas y Fisiologicas, facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia , Lima, Peru
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Yan X. Pro: All dwellers at high altitude are persons of impaired physical and mental powers. High Alt Med Biol 2014; 14:208-11. [PMID: 24067176 DOI: 10.1089/ham.2013.1026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Xiaodan Yan
- New York University School of Medicine , New York, New York
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Zhang J, Zhang H, Chen J, Fan M, Gong Q. Structural modulation of brain development by oxygen: evidence on adolescents migrating from high altitude to sea level environment. PLoS One 2013; 8:e67803. [PMID: 23874449 PMCID: PMC3706444 DOI: 10.1371/journal.pone.0067803] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 05/27/2013] [Indexed: 01/08/2023] Open
Abstract
The present study aimed to investigate structural modulation of brain by high level of oxygen during its peak period of development. Voxel-based morphometry analysis of gray matter (GM) and white matter (WM) volumes and Tract-Based Spatial Statistics analysis of WM fractional anisotropy (FA) and mean diffusion (MD) based on MRI images were carried out on 21 Tibetan adolencents (15-18 years), who were born and raised in Qinghai-Tibetan Plateau (2900-4700 m) and have lived at sea level (SL) in the last 4 years. The control group consisted of matched Tibetan adolescents born and raised at high altitude all the time. SL immigrants had increased GM volume in the left insula, left inferior parietal gyrus, and right superior parietal gyrus and decreased GM in the left precentral cortex and multiple sites in cerebellar cortex (left lobule 8, bilateral lobule 6 and crus 1/2). Decreased WM volume was found in the right superior frontal gyrus in SL immigrants. SL immigrants had higher FA and lower MD at multiple sites of WM tracts. Moreover, we detected changes in ventilation and circulation. GM volume in cerebellum lobule 8 positively correlated with diastolic pressure, while GM volume in insula positively correlated vital capacity and hypoxic ventilatory response. Our finding indicate that the structural modulations of GM by high level of oxygen during its peak period of development are related to respiratory and circulatory regulations, while the modulation in WM mainly exhibits an enhancement in myelin maturation.
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Affiliation(s)
- Jiaxing Zhang
- Department of Physiology and Neurobiology, Medical College of Xiamen University, Xiamen, China
| | - Haiyan Zhang
- Department of Physiology and Neurobiology, Medical College of Xiamen University, Xiamen, China
- Department of Physiology, Weifang Nursing Vocational College, Weifang, China
| | - Ji Chen
- Department of Physiology and Neurobiology, Medical College of Xiamen University, Xiamen, China
| | - Ming Fan
- Department of Brain Protection and Plasticity, Institute of Basic Medical Sciences, Beijing, China
| | - Qiyong Gong
- Department of Radiology, Huaxi Magnetic Resonance Research Center (HMRRC), West China Hospital, Sichuan University, Chengdu, China
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Long-term adaptation of cerebral hemodynamic response to somatosensory stimulation during chronic hypoxia in awake mice. J Cereb Blood Flow Metab 2013; 33:774-9. [PMID: 23403375 PMCID: PMC3652699 DOI: 10.1038/jcbfm.2013.16] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Effects of chronic hypoxia on hemodynamic response to sensory stimulation were investigated. Using laser-Doppler flowmetry, change in cerebral blood flow (CBF) was measured in awake mice, which were housed in a hypoxic chamber (8% O₂) for 1 month. The degree of increase in CBF evoked by sensory stimulation was gradually decreased over 1 month of chronic hypoxia. No significant reduction of increase in CBF induced by hypercapnia was observed during 1 month. Voltage-sensitive dye (VSD) imaging of the somatosensory cortex showed no significant decrease in neural activation over 1 month, indicating that the reduction of increase in CBF to sensory stimulation was not caused by cerebrovascular or neural dysfunction. The simulation study showed that, when effective diffusivity for oxygen in the capillary bed (D) value increases by chronic hypoxia due to an increase in capillary blood volume, an increase in the cerebral metabolic rate of oxygen utilization during neural activation can occur without any increase in CBF. Although previous study showed no direct effects of acute hypoxia on CBF response, our finding showed that hemodynamic response to neural activation could be modified in response to a change in their balance to energy demand using chronic hypoxia experiments.
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