New Study Says the Brain May Learn Better When Tired

A new study from Tohoku University in Japan says that the brain may remember things better when it is tired. The research shows that the brain does not work the same way all day. Instead, it follows a natural rhythm. At some times of the day, the brain is better at learning and forming memories.

The researchers studied rats and found something surprising. When the rats were most tired—right before sunrise—their brains were actually better at making long-term memories. Even though the short-term signals in the brain became weaker, the brain was still in a good state to store new information.

This process is called long-term potentiation (LTP). It happens when brain cells strengthen their connections after repeating the same activity. The scientists said the brain’s environment keeps changing through the day, and this also changes how signals are processed.

To study this, the team used special rats that had light-sensitive brain cells. They flashed tiny blue lights in the rats’ visual cortex and measured the electrical signals. They did this again and again over 24 hours.
They noticed a pattern:

The brain signals were lowest before sunrise.

The signals were highest before sunset.

Then they used stronger light pulses to see when the brain would form long-term memory links. When the pulses were given before sunrise, the brain showed a strong and lasting effect. But when the same test was done before sunset, the brain did not show any long-term change.

The scientists believe this difference is caused by adenosine, a chemical in the brain. Adenosine builds up during the day and makes us feel sleepy. It also slows down brain activity. To test this, the researchers gave the rats a drug called DPCPX, which blocks adenosine’s A1 receptors.

The result was interesting:

Before sunrise, the drug made the brain’s response stronger.

Before sunset, the drug had no effect.

This means that adenosine may help prepare the brain for deeper learning when we are tired.

What does this mean for humans?
Rats are active at night, so their “sunrise” time is similar to evening for humans. This suggests that humans may learn better later in the day, after hours of working or studying, but before going to sleep.

However, experts warn that this does not mean students should stay up very late. A small amount of tiredness may help learning, but lack of sleep harms focus, memory, and health. The best time to study difficult topics might be early evening, followed by good sleep to help the brain store the information.

The study only looked at one part of the brain, so more research is needed. Scientists are still not sure if the same effect happens in memory centers like the hippocampus. Every person is also different—some people focus better in the morning, while others learn better at night.