AMYGDALA ACTIVITY AT ENCODING CORRELATED WITH LONG-TERM, FREE-RECALL OF EMOTIONAL INFORMATION

Positron emission tomography of cerebral glucose metabolism in adult h uman subjects was used to investigate amygdaloid complex (AC) activity associated with the storage of long-term memory for emotionally arous ing events. Subjects viewed two videos (one in each of two separate po sitron emission tomography sessions, separated by 3-7 days) consisting either of 12 emotionally arousing film clips (''E'' film session) or of 12 relatively emotionally neutral film clips (''N'' film session), and rated their emotional reaction to each film clip immediately after viewing it, Three weeks after the second session, memory for the vide os was assessed in a free recall test, As expected, the subjects' aver age emotional reaction to the E films was higher than that for the N f ilms. In addition, the subjects recalled significantly more E films th an N films. Glucose metabolic rate of the right AC while viewing the E films was highly correlated with the number of E films recalled. AC a ctivity was not significantly correlated with the number of N films re called, The findings support the view derived from both animal and hum an investigations that the AC is selectively involved with the formati on of enhanced long-term memory associated with emotionally arousing e vents.