Research

Remembering experienced events is a key element of human memory that entails recovery of spatial, perceptual, and mental state details. While problems with this normally have serious functional consequences, little is known about individual differences in autobiographical memory in healthy individuals. Recently, healthy adults with highly superior autobiographical capacities have been identified in other papers. Here this group reports data from three healthy, high functioning adults with lifelong severely deficient autobiographical memory with otherwise preserved cognitive function. Their self-reported selective inability to vividly recollect personally experienced events from a first-person perspective was corroborated by absence of functional magnetic resonance imaging (fMRI) and event-related potential (ERP) biomarkers associated with naturalistic and laboratory episodic recollection, as well as by behavioral evidence of impaired episodic retrieval, particularly for visual information. Yet learning and memory were otherwise intact, as long as these tasks could be accomplished by non-episodic processes. Thus these individuals function normally in day-to-day life, even though their past is experienced in the absence of recollection.

There are individual differences in the recollection of personal past events or autobiographical memory. Theory suggests that eye movements promote retrieval of spatial details from memory, yet assessment of this prediction has been limited. This group examined the relationship of eye movements to free recall of autobiographical memory and how this relationship is modulated by individual differences in autobiographical memory capacity. Participants freely recalled past episodes while viewing a blank screen under free and fixed viewing conditions. Memory performance was quantified with the Autobiographical Interview, which separates internal (episodic) and external (non-episodic) details. Their results suggest that those with congenitally strong AM rely on the visual system to produce episodic details, whereas those with lower AM retrieve such details via other mechanisms.

Autobiographical memory is a complex cognitive function that allows an individual to collect and retrieve personal events and facts, and to develop a sense of self over time. This article describes the case of DR (acronym of the fictional name Doriana Rossi), a 53-year-old woman, who complains of a specific and lifelong deficit in recalling autobiographical episodes. DR underwent a neuropsychological assessment, which revealed a deficit in episodic re-experiencing of her own personal life events. She also underwent an MRI examination to further define this impairment. DR showed reduced cortical thickness in the Retrosplenial Complex in the left hemisphere, and in the Lateral Occipital Cortex, in the Prostriate Cortex and the Angular Gyrus in the right hemisphere. An altered pattern of activity in the calcarine cortex was detected during ordering of autobiographical events according to her own personal timeline. This study provides further evidence about the existence of a severely deficient autobiographical memory condition in neurologically healthy people, with otherwise preserved cognitive functioning. Furthermore, the present data provide new important insights into neurocognitive mechanisms underpinning such a developmental condition.