Scientists call for new research into how our brains change when we’re awake after midnight


Researchers are calling for new studies to find out how our brains change when we’re awake after midnight.

You might identify with the Mind After Midnight hypothesis if you’ve ever stayed up late angrily commenting on Twitter posts, finishing another bottle of wine, eating an entire pint of ice cream from the container, or simply feeling wretched.

The hypothesis suggests that when humans are awake during the biological circadian night – after midnight for most people – there are neurophysiological changes in the brain that alter the way we interact with the world, particularly actions related to impulse control, reward processing and information processing. . The hypothesis was detailed in a recent article published in the journal Frontiers in Network Psychology,

“There are millions of people who are awake in the middle of the night, and there’s enough evidence that their brains aren’t working as well as they were during the day.” — Elizabeth B. Klerman, MD, Ph.D.

These changes can make you more likely to view the world negatively, engage in harmful behaviors, and make impulsive decisions (including those associated with addictive behaviors such as substance abuse and gambling) without fully considering the consequences.

“The basic idea is that from a high-level, global evolutionary perspective, your internal circadian biological clock is geared towards processes that promote sleep, not wakefulness, after midnight,” says Elizabeth B. Klerman. , MD, PhD, researcher in the Department of Neurology at Massachusetts General Hospital, professor of neurology at Harvard Medical School, and senior author of the paper.

Klerman describes the hypothesis as a call for researchers to conduct new studies to better understand how these circadian differences affect behavior, decision-making and work performance at night. These might identify strategies that can help people cope.

The findings could have far-reaching effects on people who have to be awake at night to work, including pilots, police officers, healthcare workers and military personnel. The research could also lead to new strategies to reduce substance use disorders, violent crimes, suicides and other harmful behaviors.

“There are millions of people who are awake in the middle of the night, and there’s enough evidence that their brains aren’t functioning as well as they were during the day,” Klerman says. “My plea is for more research to look at this because their health and safety and that of others is affected.”

Bad things happen after dark

At night, people are at higher risk for engaging in harmful behaviors such as suicide, violent crime and substance use, previous research has found.

For example, Michael L. Perlis, PhD, associate professor of psychology at the University of Pennsylvania Perelman School of Medicine and co-author of the Mind After Midnight hypothesis, found that if you adjust to the number of people awake at one point , suicides are statistically more likely to occur at night.

Homicide and other violent crimes are also more common at night, as are the risks of illicit or inappropriate use of substances such as alcohol, cannabis and opioids.

Our nighttime food choices also tend to be unhealthy, as we crave more carbohydrates, fats, and processed foods and often consume more calories than we need.

So why does all this bad behavior come out at night?

There are a few obvious answers. It’s much easier to commit a crime under cover of darkness, to begin with. Plus, there are fewer people around and awake at night to help us control our behavior. However, it is likely that there is also a biological basis.

Klerman explains that the circadian influence on neural activity in our brain changes over the course of 24 hours, leading to differences in how we process and react to the world.

For instance, positive effect– the tendency to view information in a positive light – is at its highest in the morning, when circadian influences are adapted to wakefulness, and lowest during the night, when circadian influences are adapted to sleep .

In parallel, negative effect— the tendency to view information in a negative or threatening light is highest at night.

Your body also naturally produces more dopamine at night. It can alter your reward and motivation system and increase the likelihood of engaging in risky behavior.

This biased interpretation of information is then sent to the parts of the brain responsible for decision-making, which normally work to control negative emotional distractions and focus on goal-oriented behavior.

However, at night, these parts of the brain are also subject to circadian-influenced changes that can impair decision-making, functioning, and prioritization.

Suddenly, your view of the world narrows and becomes more negative, you start making poor decisions, and the mental map you create of the world around you may no longer correspond to reality.

The result? You could end up drinking too much, missing a crucial patient diagnosis, crashing an oil tanker into rocks, or worse.

Klerman experienced some of those feelings firsthand when she struggled to fall asleep after suffering severe jet lag on a trip to Japan.

“While part of my brain knew I would eventually fall asleep, as I lay there and watched the clock ticking, I was beside myself,” she recalls.

“Then I thought, ‘What if I was a drug addict? I would be trying to get drugs right now. Later I realized that could also be relevant if it happened. involved suicidal tendencies, substance abuse or other impulsive disorder, gambling or other addictive behavior How can I prove it?

Test the hypothesis

The need for proof is essential here. It is essential to note that Mind After Midnight is still a hypothesis, which will need to be validated by carefully constructed research studies.

Ironically, the best way to collect this data without the disconcerting effects of sleep loss will require the researchers and study staff themselves to be awake and working past midnight, such as taking resonance imaging images. functional magnetic resonance imaging (fMRI) of study participants whose sleep cycles were carefully adjusted for nocturnal wakefulness or conduct of other protocols.

“Most researchers don’t want to be notified in the middle of the night. Most research assistants and technicians don’t want to be awake in the middle of the night,” Klerman concedes.

“But we have millions of people who have to be awake at night or who are awake at night unintentionally. Some of us will have to be inconvenienced to better prepare them, heal them, or do whatever we can to help them.

Reference: “The Mind After Midnight: Nocturnal Wakefulness, Behavioral Dysregulation, and Psychopathology” by Andrew S. Tubbs, Fabian-Xosé Fernandez, Michael A. Grandner, Michael L. Perlis and Elizabeth B. Klerman, March 3, 2022, Frontiers in network physiology.
DOI: 10.3389/fnetp.2021.830338


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