The neural correlates of memory for a life-threatening event: An fMRI study of passengers from flight AT236

Abstract

We investigated the neural correlates of remote traumatic reexperiencing in survivors of a life-threatening incident: the near crash of Air Transat (AT) Flight 236. Survivors' brain activity was monitored during video-cued recollection of the AT disaster, September 11^th, 2001 (9/11), and a comparatively non-emotional (neutral) event. Passengers showed a robust memory enhancement effect for the AT incident relative to the 9/11 and neutral events. This traumatic memory enhancement was associated with activation in the amygdala, medial temporal lobe, anterior and posterior midline, and visual cortex in passengers. This brain-behavior relationship also held in relation to 9/11, which had elevated significance for passengers given its temporal proximity to the AT disaster. This pattern was not observed in a comparison group of non-traumatized individuals who were also scanned. These findings suggest that remote, traumatic memory is mediated by amygdalar activity, which likely enhances vividness via influences on hippocampal and ventral visual systems.

Figure 1

(a) Mean number of internal (episodic) and external (non-episodic) details recalled for the AT disaster (AT), September 11, 2001 (9/11), and a neutral event (NEUTRAL), for the passengers and comparison participants (controls). Error bars represent standard error of the mean. (b) The graph displays correlations from the significant latent variable (LV) from the partial least squares (PLS) analysis in passengers for all three memory conditions (also see Figure S2). Correlations express how strongly internal (episodic) detail generation was correlated with the pattern of brain regions (i.e., brain scores) that were reliable for the LV (no reliable pattern was observed for external details; see main text). Error bars indicate confidence intervals, with condition differences denoted by non-overlapping error bars. The mean correlation for each condition reliably contributes to the LV if the error bar does not cross zero. The bootstrap ratio map is overlaid on a standard template (Talairach & Tournoux, 1988), which demonstrates clusters with positive bootstrap ratios that were associated with positive mean correlations. A rectangular overlay indicates significant bootstrap ratios in the amygdalae and hippocampi (also see Table 1). Below the PLS graph, scatterplots are displayed to illustrate the individual distribution of brain scores versus internal details. R, right; L, left.