Brain Connectivity and Corticospinal Excitability in Response to Moderate Hypoxia
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-65
SponsorUniversite du Littoral Cote d'Opale
About this trial
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.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
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
Disqualifiers
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)
Trial design
Design model
Crossover
Treatments tested in this trial
Moderate hypoxia
DeviceAltitude conditions (normobaric hypoxia) will be reproduced using the OnePlus VA device (GO2Altitude, Biomedtech, Melbourne, Australia). This device modulates the fraction of inspired oxygen (FiO₂) through a patented semi-permeable membrane system developed by the company. It thereby produces a gas mixture that is inhaled by the participant through a mask. This device included an oxygen-reduction algorithm, that adjusts the FiO₂ in real time according to a target peripheral oxygen saturation (SpO₂ = 85-90%).
Normoxia
DeviceAmbient air will be delivered through the same mask as that used during the hypoxia conditions.
Transcranial Magnetic Stimulation
DeviceSingle- and paired-pulse TMS will be applied over the primary motor cortex (M1) to assess corticospinal excitability, along with intracortical inhibitory and facilitatory mechanisms. Motor-evoked potentials will be recorded from the abductor pollicis brevis (APB) muscle of the dominant hand.
Treatment groups
36 Participants
are divided into 3 treatment groupsGroup A: NormoxiaSham comparator 2 interventions
Group B: Continuous moderate hypoxiaExperimental treatment 2 interventions
Group C: Intermittent moderate hypoxiaExperimental treatment 2 interventions
Trial outcomes
Primary outcomes
1
Electrical brain activity
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.
Time frame
Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.2
Haemodynamic activity
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).
Time frame
Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.Secondary outcomes
1
Corticospinal excitability
Corticospinal excitability will be assessed using transcranial magnetic stimulation (TMS) applied to the primary motor cortex. Motor evoked potentials (MEPs) are recorded using surface electromyography from the abductor pollicis brevis (APB) muscle of the dominant hand.The primary outcome will be the slope of the I/O curve.
Time frame
Assessed at baseline and immediately post-intervention during each of the three experimental sessions (i.e., intermittent moderate hypoxia, continuous moderate hypoxia, normoxia).2
EEG brain connectivity
Resting-state cortical connectivity will be examined using the EEG data, on which coherence analyses will be applied. The outcome measure will be the degree of functional connectivity between cortical regions, quantified through coherence values across specific frequency bands (e.g., alpha, beta), reflecting the synchronisation of neural activity between these regions.
Time frame
Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.3
fNIRS brain connectivity
Resting-state cortical connectivity will be examined using the fNIRS signals, through correlations of deoxyhaemoglobin (HbR) between the cortical regions of interest. The outcome measure will be the strength of functional connectivity between these regions, quantified by the correlation coefficients of haemodynamic fluctuations, reflecting the synchrony of cortical activity at rest.
Time frame
Assessed throughout the intervention, at Day 2, 3, and 4 of the protocol.Sponsors and contacts
Click on the lead sponsor to view all of their trials.
Source ClinicalTrials.gov