Brain Connectivity and Corticospinal Excitability in Response to Moderate Hypoxia
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 36
- 试验地点
- 1
- 主要终点
- Electrical brain activity
研究概览
简要总结
Hypoxia, defined as a reduction in the availability of oxygen, induces significant physiological adaptations. While the deleterious effects of severe and chronic hypoxia are well documented, several studies indicate that moderate hypoxia - particularly when administered intermittently - may produce beneficial effects on cardiometabolic health (e.g., improved regulation of blood pressure and better glycaemic control). However, its impact on the dynamics of brain circuits in humans remains relatively underexplored. The present project aims to characterise the effects of continuous and intermittent moderate hypoxia on resting-state brain dynamics in healthy adults. To this end, simultaneous electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) recordings will be conducted in order to extract functional and haemodynamic markers of brain activity. This project will contribute to a better understanding of the neurophysiological mechanisms associated with hypoxic conditioning and to the assessment of its potential application in innovative therapeutic approaches.
详细描述
Hypoxia refers to a condition in which the availability of oxygen (O₂) is reduced relative to normal conditions. While severe hypoxia is well known for its deleterious effects, moderate hypoxia - particularly when administered intermittently - may produce potentially beneficial effects on cardiometabolic health, such as improved regulation of blood pressure and enhanced energy metabolism.
Animal models indicate that hypoxia can promote the expression of neurotrophic factors, stimulate neuroplasticity, and enhance cerebrovascular function. In humans, several studies suggest that intermittent hypoxia induces more pronounced cardiometabolic adaptations than continuous hypoxia and may improve certain cognitive functions in older adults. Recent findings also indicate that moderate hypoxia alters spontaneous brain activity at rest, particularly in the alpha frequency band, suggesting a possible influence on functional brain networks.
However, the effects of moderate hypoxia on resting-state brain dynamics remain poorly documented in humans. A detailed characterisation of both the electrical and haemodynamic responses of the brain is therefore required in order to better understand the potential adaptive processes involved and to evaluate the relevance of intermittent hypoxia as a non-pharmacological intervention for optimising brain health.
The primary objective of this project is to evaluate the effects of continuous and intermittent moderate hypoxia on resting-state brain dynamics in healthy individuals. To this end, simultaneous EEG and fNIRS recordings will be collected in order to extract functional markers of resting brain activity. A secondary objective is to investigate the impact of moderate hypoxia on brain connectivity and corticospinal excitability.
This is a single-centre exploratory descriptive study. Each participant will be assessed during three experimental sessions (i.e. intermittent hypoxia, continuous hypoxia, and normoxia) separated by at least one week and presented in a pseudo-randomised order. During the hypoxic periods, a peripheral oxygen saturation (SpO₂) between 85% and 90% will be targeted.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Male or female aged 18 to 65 years
- •Healthy right- or left-handed individuals with no self-reported neurological disorders or history of neurological conditions (e.g., epilepsy, stroke, brain or spinal surgery, or neurological diseases affecting motor or sensory function such as multiple sclerosis, or neurodegenerative diseases such as Parkinson's or Alzheimer's)
- •Individuals who have provided informed consent and have sufficient proficiency in French
- •Participants affiliated with, or beneficiaries of, a social security scheme
排除标准
- •Body mass index (BMI) greater than 30 kg/m²
- •Diagnosed and untreated obstructive sleep apnoea syndrome
- •Inability to provide informed consent
- •History of cardiac (e.g., ischaemic heart disease, heart failure) and/or respiratory disorders (e.g., COPD, chronic respiratory insufficiency, persistent or uncontrolled asthma)
- •Current smokers
- •Contraindications to TMS (e.g., uncontrolled epilepsy, intracranial metallic foreign body, hearing aid or cochlear implant, implanted stimulator or pump, scalp lesions, elevated intracranial pressure, cerebrospinal fluid shunt)
- •Use of psychotropic medication
- •Individuals under legal guardianship or curatorship
- •Pregnant or breastfeeding women
- •Participants who have flown by air or travelled to terrestrial altitudes above 1500 metres within the seven days prior to inclusion
研究组 & 干预措施
Normoxia
The sham condition will consist of 30 minutes of continuous exposure to ambient air, inhaled through the same mask as that used during the hypoxia conditions.
干预措施: Normoxia (Device)
Normoxia
The sham condition will consist of 30 minutes of continuous exposure to ambient air, inhaled through the same mask as that used during the hypoxia conditions.
干预措施: Transcranial Magnetic Stimulation (Device)
Continuous moderate hypoxia
The duration of exposure to continuous hypoxia will be 30 minutes. A peripheral oxygen saturation (SpO₂) between 85% and 90% will be targeted. Hypoxic exposure will take place at rest, with the participant comfortably seated. In addition, the hypoxic device used in the study is equipped with a safety system allowing a minimum fraction of inspired oxygen (FiO₂) to be defined. This threshold will be set at 10%, ensuring that the FiO₂ cannot fall below this value.
干预措施: Moderate hypoxia (Device)
Continuous moderate hypoxia
The duration of exposure to continuous hypoxia will be 30 minutes. A peripheral oxygen saturation (SpO₂) between 85% and 90% will be targeted. Hypoxic exposure will take place at rest, with the participant comfortably seated. In addition, the hypoxic device used in the study is equipped with a safety system allowing a minimum fraction of inspired oxygen (FiO₂) to be defined. This threshold will be set at 10%, ensuring that the FiO₂ cannot fall below this value.
干预措施: Transcranial Magnetic Stimulation (Device)
Intermittent moderate hypoxia
The intermittent hypoxia condition will consist of six periods of 5 minutes of hypoxia interspersed with 5-minute periods of normoxia. During the hypoxic periods, a SpO₂ between 85% and 90% will be targeted. As in the continuous condition, hypoxic exposure will take place at rest, with the participant comfortably seated. The hypoxic device also includes a safety system allowing a minimum FiO₂ to be defined; this threshold will be set at 10%, ensuring that the FiO₂ cannot fall below this value.
干预措施: Transcranial Magnetic Stimulation (Device)
Intermittent moderate hypoxia
The intermittent hypoxia condition will consist of six periods of 5 minutes of hypoxia interspersed with 5-minute periods of normoxia. During the hypoxic periods, a SpO₂ between 85% and 90% will be targeted. As in the continuous condition, hypoxic exposure will take place at rest, with the participant comfortably seated. The hypoxic device also includes a safety system allowing a minimum FiO₂ to be defined; this threshold will be set at 10%, ensuring that the FiO₂ cannot fall below this value.
干预措施: Moderate hypoxia (Device)
结局指标
主要结局
Electrical brain activity
时间窗: Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.
Electroencephalography (EEG) data will be recorded using a SAGA system (TMSi, Einsteinweg, The Netherlands). This system includes 64 Ag/AgCl pin-type electrodes. An additional electrode will be positioned on either the left or right mastoid. The primary outcome will be the variation in spectral power within the alpha frequency band.
Haemodynamic activity
时间窗: Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.
A Brite system (Artinis, Einsteinweg, The Netherlands) will be used to collect functional near-infrared spectroscopy (fNIRS) data. The equipment comprises four LED emitters and four photodiode receivers. A nine-channel montage will be designed to cover the regions of interest, namely the dorsolateral prefrontal cortex, the ventromedial prefrontal cortex, and the anterior prefrontal cortex. The primary outcome will be the variation in deoxyhaemoglobin (HbR).
次要结局
- Corticospinal excitability(Assessed at baseline and immediately post-intervention during each of the three experimental sessions (i.e., intermittent moderate hypoxia, continuous moderate hypoxia, normoxia).)
- EEG brain connectivity(Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.)
- fNIRS brain connectivity(Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.)