Anesthesia and Functional Connectivity: An Analysis of fMRI Changes

Stopped early · Not applicable

Conditions studied: Changes in Brain Network Connectivity

In brief

Functional connectivity is defined as a correlation in neural activity between distinct regions of the brain. Several recent studies have demonstrated areas of low-frequency functional connectivity inherent to brain tissue at rest. These oscillations can be measured using functional magnetic resonance imaging (fMRI) and appear to be synchronized between related areas of the brain. To date, no investigators have examined the effects of low-dose anesthesia on functional connectivity. This study will image the human brain under conditions of rest, and low-dose anesthetic induced sedation. Quality of the acquired signals will be evaluated and functional networks in the brain will be examined. Of interest is whether administration of a low-dose anesthetic disrupts functional connectivity in the brain, and whether a disruption of functional connectivity is responsible for the reported analgesic and antidepressant effects of a anesthetic. Participation in the study includes four visits: an in-person interview, an initial fMRI scan, the anesthesia infusion, and a second fMRI scan. There is an optional follow-up fMRI scan one week post infusion.

Key facts

Study ID

NCT02196259

Run by

University of Michigan

People needed

16

Starts

2008-02-01

Expected to finish

2015-05-01

Last updated by the study team

2017-05-02

Who can join

Age: 18 and older, up to 65. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• (4) Ability to tolerate small, enclosed spaces without anxiety; (6) English fluency.

You may not qualify if…

• Pregnant or trying to become pregnant.
• history of serious head injury;
• possibility of ferrous metals within the body, e. g. aneurysm clips, retained particles; or metal that would impair the magnetic resonance (MR) signal, e.g., some dental hardware;
• Smoking usage > 10 cigarettes per day
• Daily intake of caffeine exceeds 2 cups of coffee per day
• Unstable cardiac problems (e.g. severe or poorly treated hypertension, unstable arrhythmia, etc.) or concurrent medications for which anesthesia would be contraindicated
• Patients with a current general medical illness that is life threatening or inadequately treated will be excluded: moderate-to-severe chronic pain, evidence of fracture or malignancy, inflammatory joint disease, severe physical impairment (e.g., bilateral amputation, blindness), morbid obesity, autoimmune/inflammatory diseases, cardiopulmonary disorders (i.e., angina, congestive heart failure, COPD), chronic renal insufficiency, uncontrolled endocrine or allergic disorders (i.e., hyper-/hypothyroidism, diabetes, allergic rhinitis), malignancy.
• Taking any medication, prescription or non-prescription, with psychotropic effects.
• History of psychiatric or neurological illness; History of substance abuse or dependence Positive urine toxicology screen.
• Refractory Depression Group:
• Meets all above control group screening criteria except history of psychiatric illness and prescription medication usage
• Included subjects will have a Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) diagnosis of major depressive disorder, recurrent or chronic, moderate-to-severe, without psychotic features, with medication resistance, accepted with agreement by two different psychiatrists. For this study, treatment resistance is defined as ≥2 failed adequate antidepressant trials.
• Patients with a DSM-IV diagnosis of bipolar disorder, schizophrenia, or schizoaffective disorder will be excluded. Any history of antidepressant- or substance- induced hypomania or mania will be excluded.
• Subjects will be free of comorbid substance abuse or dependence for at least 3 months, with a negative urine toxicology screen.
• No current suicide plan or intent.
• Comorbid Axis I anxiety disorder diagnoses will be permitted if they do not require current treatment.

Where it is running

• University of Michigan - fMRI Laboratory — Ann Arbor, Michigan, United States

Full record on ClinicalTrials.gov

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