P300 is Unaffected by Glucose Increase

The effects of glucose ingestion on the P3(00) event-related brain potential (ERP) were investigated by using a visual stimulus oddball paradigm in which subjects discriminated between checkerboard (target) and horizontal line (standard) stimuli. Subjects were assessed for six consecutive trial blocks that were spaced 20 min apart on two different occasions. For the glucose condition, an initial baseline trial block was recorded followed by ingestion of 100 mg of glucose and the remaining five trial blocks recorded. For the water condition, the same procedure was employed with water ingested instead of glucose. Blood glucose levels, heart rate, and body temperature measures also were obtained before each trial block. P3 amplitude and latency did not change across trial blocks for the glucose/water conditions. No glucose/water effects were observed for the N1, P2, or N2 components as well. Blood glucose levels and heart rate increased for the glucose but not the water condition; body temperature decreased with the ingestion of both glucose and water and then returned to baseline levels. These findings suggest that ERPs are not influenced by increases of blood glucose level and are discussed in the context of previous ERP studies employing glucose manipulations.