Metabolic Changes in the Activated Human Visual Cortex During Mild Hypoxia

NCT02482571 | Completed Results DMC

• 1 other identifier: 201503M65382
• Study Type: interventional
• Target: 25
• Locations: 1 country
• Sites: 1

Brief 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).

Conditions

Brain Hypoxia

Keywords

Functional MRS; Glutamate

Outcome Measures

Primary Outcomes (2)

• Change in Glutamate Concentration During a Visual Stimulus Measured by fMRS at Normoxia

  Relative change in glutamate concentration from rest to visual stimulation as measured by fMRS (with water suppression) in the primary visual cortex during conditions of normoxia.

  Baseline and Visual Stimulation at 4 minutes

• Change in Glutamate Concentration During a Visual Stimulus Measured by Functional MRS at Hypoxia

  Relative change in glutamate concentration from rest to visual stimulation as measured by fMRS (with water suppression) in the primary visual cortex during conditions of hypoxia.

  Baseline and Visual Stimulation at 4 minutes

Secondary Outcomes (2)

• Brain Activity Measured by Blood Oxygenation Level Dependent (BOLD) Signal at Normoxia

  Baseline and Visual Stimulation at 30 seconds

• Brain Activity Measured by Blood Oxygenation Level Dependent (BOLD) Signal at Hypoxia

  Baseline and Visual Stimulation at 30 seconds

Study Arms (1)

Mild Hypoxia

EXPERIMENTAL

Subjects are exposed to an intervention that controls the composition of breathed air by using a gas blender (RespirAct). Subjects undergo MRI and MRS while breathing air with both normal oxygen concentration (normoxia) and reduced oxygen concentration (mild hypoxia).

Device: Mild Hypoxia

Interventions

Mild Hypoxia DEVICE

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.

Mild Hypoxia

Eligibility Criteria

• Age: 18 Years - 40 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may not qualify if:

• Subjects with any type of bio-implant activated by mechanical, electronic, or magnetic means (e.g. cochlear implants, pacemakers, neurostimulators, biostimulators, electronic infusion pumps, etc.).
• Subjects with any type of ferromagnetic bio-implant that could potentially be displaced or damaged, such as aneurysm clips, metallic skull plates, etc.
• Females.
• Subjects that exhibit noticeable anxiety and/or claustrophobia.
• Subjects who cannot adhere to the experimental protocol for any reason.
• Subjects who have cardiac or known circulatory impairment, and/or the inability to perspire (poor thermoregulatory function).
• Subjects who have known conditions which can lead to emergency medical care.
• Been diagnosed by a physician as having a psychiatric disorder, substance abuse, neurological, cardiovascular.
• Been diagnosed by a physician as having respiratory diseases.
• Had a brain tumor or stroke.
• Started taking chemotherapy or immunomodulatory agents, or had any radiation treatment that could affect the brain.
• Had two or more seizures, or been given a diagnosis of epilepsy.
• Gotten a non-removable piercing or permanent eyeliner.
• Had a head injury that caused you to lose consciousness for more than 30 minutes or have amnesia for more than 24 hours.
• Anyone with a history of sleep apnea or head trauma that may have caused Traumatic Brain Injury (TBI).

Sponsors & Collaborators

• University of Minnesota: lead

Study Sites (1)

Center for Magnetic Resoance Research, University of Minnesota

Minneapolis, Minnesota, 55455, United States

Location

Related Publications (2)

• Ho YC, Vidyasagar R, Shen Y, Balanos GM, Golay X, Kauppinen RA. The BOLD response and vascular reactivity during visual stimulation in the presence of hypoxic hypoxia. Neuroimage. 2008 Jun;41(2):179-88. doi: 10.1016/j.neuroimage.2008.02.048. Epub 2008 Mar 6.

  PMID: 18396415 BACKGROUND

• Tuunanen PI, Murray IJ, Parry NR, Kauppinen RA. Heterogeneous oxygen extraction in the visual cortex during activation in mild hypoxic hypoxia revealed by quantitative functional magnetic resonance imaging. J Cereb Blood Flow Metab. 2006 Feb;26(2):263-73. doi: 10.1038/sj.jcbfm.9600186.

  PMID: 16079793 BACKGROUND

Related Links

• Profile of Principle Investigator

MeSH Terms

Conditions

Hypoxia, Brain

Condition Hierarchy (Ancestors)

Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Hypoxia; Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Results Point of Contact

• Title: Silvia Mangia, PhD
• Organization: University of Minnesota

mangia@umn.edu

6126254920

Study Officials

• Silvia Mangia, PhD

  University of Minnesota

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 23, 2015
• First Posted: June 26, 2015
• Study Start: August 13, 2015
• Primary Completion: September 26, 2016
• Study Completion: September 26, 2016
• Last Updated: March 19, 2019
• Results First Posted: May 24, 2018

Record last verified: 2019-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)