Retrieving Autobiographical Memories of Painful Events Activates the Anterior Cingulate Cortex and Inferior Frontal Gyrus

Patients will often reflect on the meaning of a painful episode, as, for example, when completing questionnaire measures of subjective pain experience or in clinical interviews. Neuroimaging studies of the human cortical and subcortical physical pain response have identified a neural network consistently referred to as the "pain matrix." We used functional magnetic resonance imaging to investigate whether the pain matrix could be activated through the retrieval of memories relating to previously painful events, in the absence of any direct peripheral noxious input. Fourteen pain-free participants were explicitly instructed to recall autobiographical memories of painful episodes in response to pain-related words and non-painful episodes in response to equally salient but non-pain words. Memories triggered by pain-related words produced significantly greater activation of left caudal anterior cingulate cortex (BA32′), and left inferior frontal gyrus (BA44, extending to BA47/45) more than memories triggered by equally salient but non-pain words. We suggest that these activations demonstrate a semantic retrieval process for pain-related memories, which may provide a means of cognitively reappraising the memory of the painful episode, thus allowing the person to elaborate on the circumstances surrounding the event, without physically re-experiencing it. Perspective: The present study reveals a putative neural mechanism for the retrieval of autobiographical memories of previously painful events, which may provide a means of cognitively reappraising a painful episode, without physically re-experiencing it. This finding has implications for understanding disease mechanisms of chronic pain and their impact on subsequent treatment. © 2007 American Pain Society.