Cerebral Responses to Insulin Induced Hypoglycemia

The purpose of this study is to better understand the effect of low blood sugar
(hypoglycemia) on blood flow and biochemistry in the brain. Hypoglycemia is a serious
complication of diabetes treatments. It has been previously observed that hypoglycemia causes
an increase in blood flow to certain parts of the brain, but it has been difficult to
determine which parts of the brain specifically have an increase in blood flow. With new
technology, it is now possible to determine the rate of blood flow in very small parts of the
brain. The investigator expects that people with type 1 diabetes and hypoglycemia
unawareness, poorly controlled diabetes, and normal subjects will have different rates of
blood flow to different parts of the brain in response to hypoglycemia. Having a greater
understanding of how the brain adapts to hypoglycemia may help us develop better ways to
treat diabetes more safely.

Inclusion Criteria:

- well controlled type 1 diabetes (hemoglobin A1C <7.5%)

- healthy controls

Exclusion Criteria:

- History of stroke, seizures, neurosurgical procedures, or arrhythmias

- Use of drugs that can alter GABA (gamma-aminobutyric acid) metabolism (such as
benzodiazepines).

- Subjects must also meet requirements for a study in the magnet, which includes weight
less than 300 lbs and the absence of metallic substances in their body.