The unexpected finding was made by neurosurgeons trying to find out if stimulating certain areas of the hypothalamus could suppress the appetite of a 50-year-old obese man.
Animal studies have shown that stimulating these appetite suppressant sites can change eating behaviours.
However, when the Canadian team tried to stimulate these brain areas in the patient, he experienced a sudden sensation of deja vu and recalled details of sitting in a park with friends when he was 20.
After three weeks of continuous hypothalamic stimulation, results showed the patient had made significant improvement on two learning tests.
Annals Neurol 2008 Online, live links at www.healthcarerepublic.com.