Most people who have stayed up all night are familiar with this feeling: “tired but active and connected to the world around them.” Although the body is tired, the brain feels happy and a little crazy with a feeling of dizziness.

Feelings you may experience while staying up all night, on holidays, traveling or even late nights for school exams.

Neuroscientists at Northwestern University were the first to discover the scientific reasons for this emotional effect. According to a study published in the renowned neurological journal Neuron (Thursday), a night of severe sleep deprivation increases dopamine release and increases synaptic plasticity in the brain, which leads to rewiring of its synapses and maintains a lively mood. Next days.

According to the study, these new findings could help researchers better understand how moods change naturally. It could also lead to a more complete understanding of how fast-acting antidepressants (such as ketamine) work and help researchers identify previously unknown targets for new antidepressant drugs.

In this context, Professor Evgenia Kosorovetsky, neuroplasticity expert, associate professor of neurobiology at Northwestern University and researcher of the study, says: “Chronic sleep deprivation has been well studied before, and its harmful effects are widely documented, but short-term sleep deprivation – the equivalent of a student staying up all night before an exam – This is something we understand less.

He added in Asharq Al-Awsat: “We found that lack of sleep leads to a strong anti-stress effect and rewires the brain’s synapses,” emphasizing, “Our unusual activities like spending a sleepless night can radically change the brain. Less than hours.” He explains: “Even the mundane choices we make in life have a significant (and rapid!) impact on our brains, altering our synapses, which can lead to changes in communication between the billions of neurons in the brain.”

Symptoms of insomnia

Scientists have long known that severe sleep disturbances are associated with altered mental states and behaviors. For example, changes in sleep and circadian rhythms in patients may lead to manic or sometimes the opposite of depressive episodes.

In turn, Mingxing Wu, a postdoctoral fellow at Northwestern University and lead researcher of the study, says: “It is interesting that mood changes after severe sleep loss seem to be very real in healthy people, as happened to me and many others. ” He explains: “But the precise mechanisms in the brain that lead to these effects are poorly understood.”

To investigate these mechanisms, Kosorovetsky and his team developed a new experiment to induce severe sleep loss in mice with genetic predispositions associated with human mood disorders. After a sleepless night, the animals’ behavior became more aggressive, characterized by hyperactivity and increased sexual activity compared to a control group that experienced a regular night’s sleep.

The researchers measured the activity of dopamine neurons, which are responsible for the brain’s response to reward, and found that activity increased during short periods of sleep deprivation. “We are interested in identifying specific areas of the brain responsible for behavioral changes,” says Kosorowetsky.

He and his team studied 4 areas in the brain responsible for dopamine release. After monitoring its release in these regions after severe sleep loss, the researchers discovered that three of the four regions (prefrontal cortex, nucleus accumbens, and hypothalamus) were involved in producing this effect.

But the team wanted to reduce the results further, so they systematically silenced dopamine reactions. “The antidepressant effect persisted until we silenced the prefrontal cortex, which means it’s a clinically relevant area when looking for therapeutic targets in depression,” says Kosorovetsky.

Although most behaviors (such as hyperactivity and increased sexual activity) disappear within hours after severe sleep deprivation, the antidepressant effect persists for several days.

Adverse effects

“If you’re routinely deprived of sleep, the various chronic effects that can occur are equally harmful,” adds Kosorowetsky. “But if it happens in a quick way, you can imagine situations where it might be useful to be more cautious for a while.”

But she cautions against staying up all night to boost the mood, explaining: “We know the importance of a good night’s sleep. “I’d say going to the gym or taking a nice walk is better than staying up all night on purpose.”

He concludes: “When designing treatment strategies for patients suffering from mood disorders, it should be remembered that sleep patterns play an important role and can have a detrimental effect on the effectiveness of drugs or therapies, especially those acting through the dopamine system. .” .