NCT02482571

Metabolic Changes in the Activated Human Visual Cortex During Mild Hypoxia

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 25 (actual)
• Sponsor: University of Minnesota · Academic / Other
• Sex: Male
• Age: 18 Years – 40 Years
• Healthy volunteers: Accepted

Summary

The primary objective of this research is to measure changes in neurochemical concentrations during stimulation of the primary visual cortex, in both conditions of normoxia (normal oxygen availability) and induced mild hypoxia (reduced oxygen availability).

Detailed description

The goal is to determine the effect of mild hypoxia on human brain energy metabolism of healthy young adult subjects. For this purpose, the Investigator will utilize non-invasive imaging modalities based on functional magnetic resonance spectroscopy (fMRS) to estimate metabolic changes during a visual stimulus, while subjects are exposed to well-controlled gas mixtures that resembles conditions of either normoxia or mild hypoxia. Identifying the impact of mild hypoxia on functional brain energy metabolism in the healthy human brain is a crucial step for generating hypotheses in multiple patient populations that experience mild hypoxia as consequence of their pathological condition, such as in sleep apnea and traumatic brain injury. The Investigator hypothesize that the energetic demands of neuronal activation as revealed by fMRS will not be affected by mild hypoxia.

Conditions

• Brain Hypoxia

Interventions

Type	Name	Description
DEVICE	Mild Hypoxia	During normoxia, the computer-controlled gas blender provides a gas mixture that generates pressures of expired O2 and CO2 similar to the resting values measured for each subject (32-35mmHg and 100-110 mmHg, respectively). During mild hypoxia, we will target the same expired CO2 of normoxia and a 60 mmHg reduction of expired O2 from the resting value (to a minimum limit of 50 mmHg), which is expected to reduce arterial oxygen saturation to 82-85%. In mild hypoxia, the fraction of inspired oxygen is reduced from \~21% (room air) to \~12% (equivalent to an altitude of 4000 meters). During both conditions of normoxia and mild hypoxia, the brain activity of subjects is monitored with functional magnetic resonance spectroscopy (fMRS) while they are presented with visual stimuli.

Timeline

• Start date: 2015-08-13
• Primary completion: 2016-09-26
• Completion: 2016-09-26
• First posted: 2015-06-26
• Last updated: 2019-03-19
• Results posted: 2018-05-24

Locations

1 site across 1 country: United States