People suffering from anterograde amnesia—caused by damage to the brain’s hippocampus—can remember details about their past but lack the ability to form new memories. Not everything gets lost, however. In April University of Iowa researchers observed that emotions persist in these amnesiac individuals even after they forget the cause, an important clue about how the brain stores different kinds of information.
Neuropsychologist Justin Feinstein and his collaborators showed a group of patients with severe anterograde amnesia two series of video clips (including scenes from The Notebook and America’s Funniest Home Videos) to induce sadness and happiness in their subjects. Memory tests administered several minutes later showed that the patients retained few, if any, specific details about the clips. But emotion measurements showed that the feelings induced by the videos lingered, with sadness outlasting happiness.
“Even though emotions seem fused together with memories in our stream of consciousness, it turns out that this is not the case,” Feinstein says.
Patients suffering from Alzheimer’s disease and dementia have damage to the hippocampus similar to that seen in people with anterograde amnesia. The new study therefore suggests that a visit or telephone call with such patients could have profound positive effects even if the interaction is soon forgotten, Feinstein says.