Episodic-like memory is preserved with age in cuttlefish. Issue 1957 (25th August 2021)

• Record Type: Journal Article
• Authors: Schnell, Alexandra K.; Clayton, Nicola S.; Hanlon, Roger T.; Jozet-Alves, Christelle
• Is Part Of: Proceedings. Volume 288:Issue 1957(2021)
• Publication Date: 2021-08-25
• Subjects: what–where–when memory -- ageing -- semantic-like memory -- time-place learning -- cephalopod cognition -- comparative cognition; Biology -- Periodicals; 570.5
• DOI: 10.1098/rspb.2021.1052
• Languages: English
• ISSNs: 0962-8452

Abstract

Abstract : Episodic memory, remembering past experiences based on unique what–where–when components, declines during ageing in humans, as does episodic-like memory in non-human mammals. By contrast, semantic memory, remembering learnt knowledge without recalling unique what–where–when features, remains relatively intact with advancing age. The age-related decline in episodic memory likely stems from the deteriorating function of the hippocampus in the brain. Whether episodic memory can deteriorate with age in species that lack a hippocampus is unknown. Cuttlefish are molluscs that lack a hippocampus. We test both semantic-like and episodic-like memory in sub-adults and aged-adults nearing senescence ( n = 6 per cohort). In the semantic-like memory task, cuttlefish had to learn that the location of a food resource was dependent on the time of day. Performance, measured as proportion of correct trials, was comparable across age groups. In the episodic-like memory task, cuttlefish had to solve a foraging task by retrieving what–where–when information about a past event with unique spatio-temporal features. In this task, performance was comparable across age groups; however, aged-adults reached the success criterion (8/10 correct choices in consecutive trials) significantly faster than sub-adults. Contrary to other animals, episodic-like memory is preserved in aged cuttlefish, suggesting that memory deterioration is delayed in this species.