IMPAIRED DELAY EYEBLINK CONDITIONING IN AMNESIC KORSAKOFFS PATIENTS AND RECOVERED ALCOHOLICS

The performance of amnesic Korsakoff patients in delay eyeblink classi cal conditioning was compared with that of recovered chronic alcoholic subjects and healthy normal control subjects. Normal control subjects exhibited acquisition of conditioned responses (CRs) to a previously neutral, conditioned tone stimulus (CS) following repeated pairings wi th an unconditioned air-puff stimulus, and demonstrated extinction of CRs when the CS was subsequently presented alone. Both amnesic Korsako ff patients and recovered chronic alcoholic subjects demonstrated an i mpairment in their ability to acquire CRs. These results indicate that the preservation of delay eyeblink conditioning in amnesia must depen d on the underlying neuropathology of the amnesic syndrome. It is know n that patients with amnesia caused by medial temporal lobe pathology have preserved conditioning. We have now demonstrated that patients wi th anmesia caused by Korsakoff's syndrome, as well as recovered chroni c alcoholic subjects, have impaired conditioning. This impairment is m ost likely caused by cerebellar deterioration resulting from years of alcohol abuse.