Conditioned hypoglycemia.

An experiment was conducted to determine whether conditioned hypoglycemia would develop in rats that never became hypoglycemic on the conditioning trials. Rats were given saline, insulin, glucose, or glucose plus insulin as the unconditioned stimulus in a classical conditioning paradigm. It was found that a change of blood glucose need not occur on the conditioning trials in order to obtain successful conditioning of a hypoglycemic response; rather, an increase of insulin was all that was necessary. An explanation of conditioned hypoglycemia as the logical response of glucoregulatory centers of the central nervous system is proposed.