How personal experience modulates the neural circuitry of memories of September 11

Brown and Kulik [Brown R, Kulik J (1977) Cognition 5:73-99] introduced the term "flashbulb memory" to describe the recall of shocking, consequential events such as hearing news of a presidential assassination. They proposed that the vivid detail of such memories results from the action of a unique neural mechanism. In the present study of personal recollections of the terrorist attacks of September 11, 2001 (9/11) in New York City, we combine behavioral and brain imaging techniques, with two goals: (i) to explore the neural basis of such memories and (ii) to clarify the characteristics of the emotional events that may give rise to them. Three years after the terrorist attacks, participants were asked to retrieve memories of 9/11, as well as memories of personally selected control events from 2001. At the time of the attacks, some participants were in Downtown Manhattan, close to the World Trade Center; others were in Midtown, a few miles away. The Downtown participants exhibited selective activation of the amygdala as they recalled events from 9/11, but not while they recalled control events. This was not the case for the Midtown participants. Moreover, only the Downtown participants reported emotionally enhanced recollective experiences while recalling events from 9/11, as compared with control events. These results suggest that close personal experience may be critical in engaging the neural mechanisms that underlie the emotional modulation of memory and thus in producing the vivid recollections to which the term flashbulb memory is often applied.