• fMRi scans [ Time Frame: 1 day ] [ Designated as safety issue: No ]
  

The studies proposed in this application seek to use non-invasive techniques to examine the impact of repeated hypoglycemia on the brain.

During the past decade many studies have shown that appropriate magnetic resonance imaging (MRI) methods may be used to assess alterations in brain regional activation in response to external stimuli or tasks. Thus, this non-invasive technique will enhance our ability to learn more about brain function, during hypoglycemia and may delineate information about the role of the brain in hypoglycemia associated autonomic dysfunction.

Inclusion Criteria:

• Healthy male and female subjects aged 18-45
• Type 1 diabetes mellitus patients aged 18-45
• Body Mass Index 21-38 kg/m2
• Normal results of routine blood test to screen for hepatic, renal, and hematological abnormalities and an EKG stress test.
• Female volunteers of childbearing potential will undergo HCG pregnancy test. Only women who are not pregnant will participate in the study.

Diabetic Subjects:

• HBA1C= 5.5-11.0%
• Duration of Type 1 Diabetes > 3 yr
• Normal bedside autonomic function

Exclusion Criteria:

All Subjects

• Prior or current history of poor health
• Abnormal results following screening tests
• Pregnancy
• Subjects unable to give voluntary informed consent
• Subjects with a recent medical illness
• Subjects with a history of hypertension, heart disease or cerebrovascular disease
• Subjects with known liver or kidney disease
• Subjects with recent weight loss or consuming a low carbohydrate diet
• Subjects taking steroids
• Subjects taking beta-blockers
• Subjects on anticoagulant drugs, anemic or with known bleeding diatheses
• Evidence of diabetic neuropathy, autonomic neuropathy, proteinuria, extensive background or proliferative retinopathy, hypertension, or cardiovascular disease