Scientists have discovered that memory can occur outside the brain

We tend to think of memory as the exclusive domain of the brain, but new research suggests that this view may be far too narrow. A New York University study shows that some ordinary human cells outside the brain can also learn and store information.

When exposed to signals that mimic learning rhythms, these cells behave much like neurons. Their responses became stronger when the stimulation was spaced out over time rather than delivered all at once.

“Learning and memory are usually associated only with the brain and brain cells, but our study shows that other cells in the body can also learn and form memories,” said Nikolay V. Kukushkin, the lead author of the study. The results suggest that learning may be a fundamental property of life itself, embedded in the way all cells process time and information.

The body remembers

The discovery centers on a principle known as the spacing effect, first described in the 19th century by psychologist Hermann Ebbinghaus. This is why we remember material better when we review it at regular intervals instead of cramming it right before a test. We have observed this effect in animals, from humans to sea slugs. Notably, it has always been linked to neuronal activity.

So Kukushkin and his team decided to test whether the same principle could apply beyond the brain. They used two types of human cells: one derived from nervous tissue and the other from kidney cells, which play no role in the nervous system. Both have been genetically modified to produce a light signal when a “memory gene,” controlled by a protein, CREB, is activated. CREB is a molecular switch that helps neurons consolidate long-term memory. It also exists in almost every cell in the body.

Then came the experience.

The researchers exposed the cells to brief pulses of chemicals that mimic the brain’s learning signals. Each pulse lasted only three minutes and the pulses were either spaced apart or delivered in one long burst.

When the pulses were spaced apart, the cells lit up more intensely and for much longer. The “memory gene” remained active for hours after training ended, especially when the pulses were spaced ten minutes apart. In contrast, when the same amount of stimulation was delivered all at once (a “massaged” pattern), the glow faded quickly.

A property of all cells?

In one trial, cells that received four spaced pulses showed 2.8 times greater activation of a memory gene controlled by CREB after 24 hours compared to those that received a continuous signal. What happened was that the cells recognized and encoded a pattern in time – the difference between signals arriving at spaced intervals and signals arriving at the same time. In other words, the information they stored was the temporal structure of the stimulation, the rhythm or timing of the chemical pulses.

“This reflects the mass and spacing effect in action,” Kukushkin said. “This shows that the ability to learn from spaced repetitions is not unique to brain cells, but could be a fundamental feature of cellular function.”

The results of the experiment were the same whether we were dealing with nerve cells or kidney cells. Even 24 hours later, the cell “remembers” how it was previously stimulated, because certain molecular switches remain altered.

“We think it’s not a property of any cell type, it’s just a generic property of all cells,” Kukushkin said. IFLScience.

Smarter than we think

If this is true, it means that memory may not require a brain at all. Instead, it could be a universal biological process – a way for cells to detect and store temporal patterns in their environment, whether that environment is a neural network or a bloodstream.

“In the future, we will have to treat our body more like the brain,” Kukushkin said. “For example, consider what our pancreas remembers about the pattern of our past meals to maintain healthy blood sugar levels – or consider what a cancer cell remembers about the pattern of chemotherapy. »

This concept could reshape medicine. If cells “remember” past exposures to drugs or nutrients, then the timing of treatments or meals may be as important as their contents or dosage. “Maybe the order of nutrients you eat is important,” Kukushkin said. IFLScience. “Perhaps the gap between these nutrients is large, and it could change the way we digest food in the future, the way we store fat, for example.”

The NYU team’s work shows that even simple cells can encode the passage of time, thereby preserving traces of experience using the same molecular machinery that gives rise to memory in animals. This doesn’t mean your kidney cells remember a melody or event from childhood, but they seem to register patterns and respond differently the next time. “Non-neuronal cells are much smarter than we think,” Kukushkin said.

The results were published in Natural communications.