Just one night can rewire the brain and reverse feelings of depression for days

Just one night can rewire the brain and reverse feelings of depression for days

Have you ever stayed up all night and ended up feeling stressed, hyperactive, or even like you were drunk? Well, scientists are looking to harness this feeling to see if it can help people with depression, and a new study in mice has revealed changes in the sleep-deprived brain that appear to cause depression.

For most of us, the idea of ​​having to give up a restful night’s sleep is not a pleasant one. But, when they have to wake up for a night shift, a long flight, or a last-minute study session, many people find that they feel surprisingly upbeat the next day. You might describe it as feeling “tired and exhausted,” dizzy, or even a little delirious (but in a good way).

If just one night’s sleep can have this kind of effect, it might help us better understand how brain changes affect our mood, and how some antidepressants, like ketamine, can take effect so quickly.

“Interestingly, changes in mood after acute sleep loss appear to be very real, even in healthy people, as they have happened to me and many others,” said Mingzheng Wu, a postdoctoral fellow at Northwestern University and first author of a new study on sleep deprivation. “. a permit. “But the precise mechanisms in the brain that lead to these effects have remained poorly understood.”

To learn more, Wu and the team conducted experiments on healthy adult mice. They devised a system to keep the animals awake while reducing the amount of stress they are exposed to, using an enclosure with an elevated platform above a slowly rotating beam. The mice could either rest on the platform, or go exploring below, but they had to keep moving to get out of the way of the beam. The researchers tested the device and found that when mice were housed in it, they got significantly less sleep.

After a night of sleep deprivation, the researchers noticed that the mice behaved in a more aggressive and sexually aroused manner. The culprit? Dopamine: the rewarding neurotransmitter.

The researchers were able to see an increase in dopamine signals in the animals’ brains, but they weren’t sure if this was specific to certain regions or an effect on the entire brain. They took a closer look at four regions—the prefrontal cortex, nucleus accumbens, hypothalamus, and dorsal striatum—monitoring them for dopamine release and then silencing them one by one.

“The antidepressant effect persisted only when we silenced dopamine inputs to the prefrontal cortex,” explained lead researcher Yevgenia Kozorovetsky. “This means that the prefrontal cortex is a clinically relevant area when searching for therapeutic targets. But it also reinforces the idea that has been building in this field recently: dopamine neurons play very important but very different roles in the brain. They are not just a homogeneous population that predicts Simply with rewards.

This point about therapeutic goals is key. According to the Centers for Disease Control and Prevention (CDC), depression affects 16 million American adults each year, and antidepressant medications are widely used. While some people have found that traditional antidepressants have a transformative effect, they are not suitable for everyone and can have significant side effects. Studies are exploring the potential of new approaches, such as anesthetic drugs, in difficult-to-treat conditions, but there is always a need for improved understanding that could lead to new treatments.

But that doesn’t mean Kozorovetsky would recommend staying up all night as a quick fix. Organisms may have evolved this state of heightened awareness at times when delaying sleep and remaining on high alert could protect them from predation and other threats, but over time, the problems of chronic sleep deprivation will begin to quickly outweigh these benefits.

However, it is an important new avenue for researchers to further explore.

“We found that lack of sleep leads to a powerful antidepressant effect and rewires the brain,” Kozorovetsky said. “This is an important reminder that our casual activities, such as a sleepless night, can radically change the brain in as little as a few hours.”

The study was published in the journal Neuron.

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