How squid’s powerful memory system defies aging


Can you remember What did you have for dinner last weekend? This ability is a function of episodic memory, and the extent to which we are able to remember the time and place of certain events typically declines with age. Squids also seem to display a form of episodic memory, but unlike humans, their ability does not diminish as they age, according to new paper Posted in Proceedings of the Royal Society B.

“Squids can remember what they ate, where and when, and use this to guide future feeding decisions,” said co-author Alexandra Schnell of the University of Cambridge, who conducted the experiments at the Marine Biological Laboratory in Woods Hole, Massachusetts. “Surprisingly, they do not lose this ability with age, despite the appearance of other signs of aging such as loss of muscle function and appetite.”

earlier this year, inform us In a study by Schnell et al turns out that Squid can delay gratification. Specifically, they can pass the famous cephalopod version Stanford Marshmallow Test: waiting a bit for its preferred prey rather than being content with a less desirable prey. Squids also performed better on a subsequent educational test—the first time such a link between self-control and intelligence has been found in a non-mammalian species.

In those experiments, the squid had to choose between two different items of prey: it could choose to eat raw shrimp right away or delay the satiation of its favorite live grass shrimp. The subject can see both options for the duration of the experiment and can give up waiting at any time and eat king prawns if they get tired of sticking to grass shrimp.

The team also subjected the squid to a learning task to assess cognitive performance. The cephalopods first learned to associate a visual symbol with a specific prey reward, then the researchers reversed the situation so that the same reward was associated with a different symbol. They found that squids were all able to wait for the best reward and withstand delays of up to 50 to 130 seconds, compared to large-brained vertebrates such as chimpanzees, crows and parrots.

This latest study focuses on whether squids have a form of episodic memory — the ability to remember unique past events with context about what happened, where it happened, and when it happened. Humans develop this ability around the age of four, and our episodic memory declines as we age. This is in contrast to semantic memory, our ability to recall acquired general knowledge without the context of space and time. It has been shown that semantic learning in humans remains relatively intact with age.

The hippocampal region of the human brain plays an important role in episodic memory, and its deterioration over time is thought to be responsible for the deterioration of our episodic memory as we age. For a long time, scientists assumed that episodic memory was uniquely human because this type of memory retrieval is associated with the conscious experience of remembering. Humans can express these aspects verbally; It is difficult to assess potential conscious experience in nonverbal animals (from a human perspective).

However, many animal species have been shown to exhibit “episodic-like” memory abilities—the term that scholars in this subfield use to “explicitly acknowledge that we do not assume human traits of language and the awareness involved in cognition to project oneself into time”, as Schnell et al. wrote in a footnote. for example, Study 1998 I found that jays remember when and where they stored their food and what the food was. Behaviors indicative of presentation-like memory have also been observed magpie birdAnd great monkeysAnd mice, And zebrafish.

Evidence of display-like memory was also shown squid. Squids lack a hippocampus, but they have a distinct brain structure and organization, complete with a head lobe that shows similarities with the connectivity and function of the human hippocampus—that is, learning and memory. Previous studies have shown that squids are sufficiently future-oriented and can improve foraging behavior and remember details of what, where and when from previous forages — hallmarks of presentation-like memory — modifying their strategy in response to changing prey conditions.



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