Similarity in activity and laterality patterns in the angular gyrus during autobiographical memory retrieval and self-referential processing

Long-term memory is arguably one of the key cognitive functions. At the neural level, the lateral parietal cortex and the angular gyrus, particularly in the left hemisphere, exhibit strong activations during autobiographical and episodic memory retrieval. In a separate sub-field, left-lateralized activations of the angular gyrus are also found during self-referential processing, defined as higher activity when a trait term is judged by participants as being related to them vs. related to someone else. The question is whether episodic/autobiographical memory retrieval and self-referential processing effects are related. In the present study, thirty participants participated in the fMRI study with two separate experiments: autobiographical memory retrieval (Experiment 1) and self-referential processing (Experiment 2). In a series of analyses, including the most critical spatial correlation analysis between experiments, we found neural similarity between autobiographical memory retrieval and self-referential processing. Given that self-referential processing was identified in a selective way, the most plausible interpretation of our findings is that self-referential processing might partly explain the activation of the left angular gyrus during autobiographical memory retrieval. Our results are in line with the seminal view of Endel Tulving that the sense of self is a fundamental attribute of long-term memory recollection. However, it should be emphasized that: a) our results do not imply that the left angular gyrus is not involved in the retrieval of episodic memory details; and b) given that our experiment included an autobiographical memory task, generalization of our results to the episodic memory laboratory tasks has yet to be tested.