The Neurobiology of Reduced Autobiographical Memory Specificity

Abstract

There has been a recent growth in investigations into the neural mechanisms underlying the problems recalling specific autobiographical events that are a core feature of emotional disorders. In this review we provide the first synthesis of this literature, taking into account brain as well as cognitive mechanisms. We suggest that these problems are driven by idiosyncratic activation in areas of the brain associated with assigning salience and self-relevance to emotional memories. Other areas associated with inhibiting distraction and constructing vivid memory representations are also important. Each of these mechanisms may work independently or in concert with one another. Importantly, this interaction between mechanisms may differ between diagnostic and demographic groups such that similar problems in specificity may be characterised by different mechanisms. Given this challenge, neuroimaging may prove useful in identifying patient-specific biomarkers for interventions. Autobiographical Memory SpecificityAutobiographical memories (AMs), defined as memories for personally experienced past events, offer examples of who we are and of failures and successes to be avoided or replicated. Some people, however, exhibit difficulty recalling specific events from their past (e.g., an occasion where they ate dinner with friends). When asked to retrieve a memory related to a cue (e.g., friend), they might instead retrieve general information (e.g., the idea of what a friend is). This tendency for reduced autobiographical memory specificity (rAMS) is one of the core cognitive mechanisms associated with emotional disorders such as depression [1-6] (Box 1 and Figure 1). rAMS is also a cognitive mechanism for which targeted interventions exist, and its amelioration through these interventions has been found to lead to an improvement in disorder symptoms [7][8][9][10]. Neuroscience research has begun to elucidate the neurobiology of specific autobiographical memory retrieval and its role amongst clinical groups who have difficulty retrieving specific memories. We provide the first synthesis of this literature. This review examines what we know about the neurobiology of autobiographical memory and memory specificity in particular. We consider what this means for why rAMS occurs and its role in emotional disorders, contrasting this neuroscience evidence with cognitive models of rAMS. We also consider what these advances in neuroscience mean for interventions seeking to improve memory specificity or to treat emotional disorders. The Biological Architecture of Autobiographical MemoryResearchers have identified a network of brain regions across the prefrontal cortex, medial temporal lobe (MTL), limbic system, and occipital lobe that is associated with the retrieval (see Glossary) and re-experiencing of AMs, irrespective of their specificity [11][12][13], but which might be differentially activated as a function of specificity (Figure 2, Key Figure). In particular, activity in lateral portions of the prefrontal cortex (PFC) has been as...

Depression diagnoses, but not individual differences in depression symptoms, are associated with reduced autobiographical memory specificity

“…In particular, research might test whether improving executive functioning using novel training protocols (Schweizer, Grahn, Hampshire, Mobbs, & Dalgleish, ; Schweizer, Hampshire, & Dalgleish, ) can in turn lead to an improvement in specificity. Nevertheless, the finding that weak verbal fluency was associated with reduced specificity in people with depression aligns with neuroscience evidence that impaired activation in areas of the brain associated with inhibiting distraction and holding information in working memory contribute towards problems recalling specific memories amongst people with depression (Barry, Chiu, Raes, Ricarte, & Lau, ). That a mechanism such as executive functioning impairments could contribute towards specificity problems in one group, such as amongst people with depression, but not another group, such as those without depression, is also in line with neuroscience studies in this area (Barry, Chiu, et al ., ).…”

Efficacy of online Memory Specificity Training in adults with a history of depression, using a multiple baseline across participants design

“…An increase in speed in retrieving specific memories, for example, might be another important variable that improves through training and which may not be realized by the first session. Another useful addition to future studies examining the optimal dose would be the use of transfer tasks, to control for the overlap of the AMT and MeST, or to examine change in the neurobiological processes underlying reduced specificity from pre- to post- intervention (Barry et al, 2018).…”

Remediating reduced memory specificity in bipolar disorder: A case study using a Computerized Memory Specificity Training

“…For this study, standard c-MeST is used . One potential interesting route is to adapt it to people with BD by taking into account unique characteristics of memory retrieval in BD (Barry, Chiu, et al, 2018). For example, as discussed previously, vivid mental imagery as part of episodic recall can act as an emotional amplifier of mood states in BD (Holmes et al, 2016).…”

“…Aspects of memory in BD might, however, also differ from UD. Barry and colleagues (Barry, Chiu, Raes, Ricarte, & Lau, ) describe in their review paper on the neurobiology of rAMS that although similar behavioral deficits were found in UD and BD, the neurophysiological underpinnings of AM recall between people with UD and BP differed. Memory retrieval in people with BD is characterized by memories with enhanced salience and emotional vividness and is processed as more self‐relevant compared to people with UD and HC (Oertel‐Knöchel et al, ; Young & Bodurka, ).…”