Neural substrates of the self‐memory system: New insights from a meta‐analysis

Abstract

The self has been the topic of philosophical inquiry for centuries. Neuropsychological data suggest that the declarative self can be fractionated into three functionally independent systems processing personal information at several levels of abstraction, including episodic memories of one's own life (episodic autobiographical memory, EAM), semantic knowledge of facts about one's own life (semantic autobiographical memory, SAM), and semantic summary representations of one's personal identity (conceptual self, CS). Our proposal here was to present a comprehensive description of the neural networks underpinning self-representations. To this aim, we performed three meta-analyses, one each for EAM, SAM, and CS, using the activation likelihood estimation (ALE) method. We expected a shift from posterior to anterior structures associated with the incrementally increasing level of abstraction of self-representations. The key finding was that EAM predominantly activates posterior and limbic regions including hippocampus. SAM is associated with anterior activations and also posterior and limbic activations in a lesser degree than EAM. CS mainly recruits medial prefrontal structures. Interestingly, medial prefrontal cortex is activated irrespective of the level of abstraction, but a more caudal part is recruited during CS, while SAM and EAM activate more rostral portions. To conclude, in line with the previous proposals, our results corroborate the idea that the declarative self is not monolithic but a multidimensional construct comprising distinct representations at different levels of abstraction.

Experience-near but not experience-far autobiographical facts depend on the medial temporal lobe for retrieval: Evidence from amnesia

“…The results of this paper build on current conceptual models that view personal memory as a form of memory that incorporates both episodic and semantic information (Conway, 2005;Haslam et al, 2011;Martinelli et al, 2013;Renoult et al, in press). However, much remains unknown about the neural and cognitive bases of personal memory.…”

“…However, much remains unknown about the neural and cognitive bases of personal memory. In their meta-analysis of functional neuroimaging research on personal memory, Martinelli et al (2013) revealed that autobiographical fact retrieval in healthy adults was associated with a widely distributed neural network that includes anterior and posterior cortical midline structures, frontal and temporal gyri, thalamus, fusiform gyrus, and the MTL. We have demonstrated that one region in this network, namely the MTL, is needed for retrieval of only a subset of autobiographical facts.…”

“…Based on this theoretical framework, experience-near autobiographical facts may share mechanisms with episodic memory and thus depend on the medial temporal lobe (MTL) for retrieval, whereas experience-far facts, once consolidated, may rely on neocortical brain regions involved in retrieval of general semantic memory (Greenberg and Verfaellie, 2010). Consistent with this idea, findings from neuropsychology (Grilli and Verfaellie, 2014;Philippi et al, 2015) and functional neuroimaging (Martinelli et al, 2013) converge on the notion that the MTL is involved in retrieval of autobiographical facts, albeit less so than in episodic memory (Grilli and Verfaellie, 2014). Moreover, Renoult et al (in press) recently demonstrated that the neural bases of autobiographical fact retrieval are distinct from but overlap with episodic memory and general semantic memory.…”

Mind-Wandering and Self-Referential Thought

“…In many studies, memories of specific personal experiences (i.e., events that happened at a particular place and time in an individual's life) are compared with the retrieval of non-personal information (e.g., non-personal semantic knowledge or stimuli that have been learned in the laboratory before the scanning session). Neuroimaging evidence indicates that such autobiographical memory retrieval is associated with activations in the mPFC, medial and lateral temporal areas, posterior cingulate/retrosplenial cortex, and inferior parietal lobes (for meta-analyses, see Kim, 2012;Martinelli, Sperduti, & Piolino, 2013;McDermott, Szpunar, & Christ, 2009;Spreng, Mar, & Kim, 2009;Svoboda, McKinnon, & Levine, 2006). Furthermore, lesion data have revealed that damage to these areas is associated with deficits in autobiographical memory retrieval (Philippi, Tranel, Duff, & Rudrauf, 2015).…”

“…A recent meta-analysis of neuroimaging studies (Martinelli et al, 2013) Subsequent studies have detected similar activations in the mPFC, posterior cingulate, and lateral temporal cortex when reflecting on personal goals, especially promotion goals (i.e., things the individual would like to achieve) (for a meta-analysis, see Stawarczyk & D'Argembeau, 2015).…”