Memory Beyond the Brain

For centuries, memory has been understood as a function exclusive to the brain. However, a recent study at New York University challenges this long-held belief, revealing that non-neural cells may also possess memory-like capabilities. The team led by Dr. Nikolay V. Kukushkin, discovered that non-brain cells can learn and store information just like neurons do. 

We tend to retain information better when we study in spaced intervals rather than in a single, intensive session—better known as cramming for a test. Researchers at New York University hypothesized that this effect might extend beyond neurons. They proposed that the molecular tools required for memory formation could also exist in non-neural cells. If non-neural cells really can remember patterns, it could change how we understand memory and how we treat diseases or design better learning methods in the future.

This discovery is exciting because it changes how we understand memory. It could help scientists develop better treatments for diseases by understanding how different cells "learn" from experience.

The Spacing Effect

The research team at New York University wanted to explore whether non-neural cells could also show memory-like behaviour. To test this idea, researchers used a neurological property called the spaced repetition effect or the spacing effect. This effect, first described by psychologist Hermann Ebbinghaus, shows that we retain information better when it is studied in intervals (spaced learning) rather than all at once (massed learning or cramming). It is a universal feature, observed in organisms from fruit flies to humans. Until now, this phenomenon was thought to be exclusive to neurons.

They developed a novel experimental system using human-derived kidney and nerve cells grown in the laboratory. They replicated learning over time by exposing the cells to chemical signals in two patterns: massed (all at once) and spaced (spread out over time), mimicking the timing of neurotransmitter release during learning. The goal was to observe whether these cells could recognize patterns of stimuli and exhibit a form of "cellular cognition."

In brain cells during memory formation, a memory gene gets activated when they detect a pattern in the information. This activation triggers a restructuring of neural connections, which is essential to form and store memories. To monitor the memory and learning process, the scientists genetically engineered these non-neural cells to produce a fluorescent protein, which would indicate when the memory gene was on and when it was off.

When chemical signals were delivered in spaced intervals, the non-neural cells activated the memory gene more robustly and for a longer duration than when the same amount of stimulation was given all at once. This demonstrated the spacing effect. The results showed that these cells could determine when the chemical pulses were repeated rather than simply prolonged, just as neurons in our brain can register when we learn with breaks rather than cramming all the material in one sitting. 

Cellular learning

The non-neural cells responded more strongly to the spaced stimuli, triggering the memory gene in a pattern similar to neural learning. “This reflects the massed-space effect in action. It shows that the ability to learn from spaced repetition isn't unique to brain cells, but, in fact, might be a fundamental property of all cells.” says Dr. Kukushkin. He says this discovery could change how we think about memory—not just in our brains, but throughout our whole body and these findings could have significant health implications. 

If cells like those in the kidney or pancreas store “metabolic patterns”, it could help explain how the body regulates important functions, such as blood sugar. For example, if the pancreas remembers when and how often we eat, it might manage insulin more efficiently, leading to improved diabetes management. Similarly, understanding how cancer cells "remember" treatment patterns might inform more effective chemotherapy protocols. 

This study challenges the long-standing neuron-centric view of memory by demonstrating that non-neural cells can exhibit memory-like responses to patterned stimuli. This suggests that memory may be a more widespread cellular property than previously believed. These findings could revolutionise our understanding of learning and memory, extending it beyond the brain to include various organs and tissues. It may help explain how organs adapt to repeated behaviours, such as meal timing, and how cancer cells might develop resistance to chemotherapy through pattern recognition. In the future, scientists might design treatments that help organs “learn” and adapt, thus opening up new ways to improve health, memory, and how we learn.

In light of these findings, a compelling question emerges—what else might our non-neural cells remember, and how could this reshape the future of medical treatment and cognitive science?

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Reference: “The massed-spaced learning effect in non-neural human cells” by N. V. Kukushkin, R. E. Carney, T. Tabassum and T. J. Carew, 7 November 2024, Nature Communications. DOI: 10.1038/s41467-024-53922-x

This study was published in the journal Nature Communications by a team at New York University. Lead author: Dr. Nikolay V. Kukushkin. Other contributors: Thomas Carew, Tasnim Tabassum, and Robert Carney. 

Michael Luke Jose | Writer, The STEM Review