The science of sleep deprivation

Dazed and confused? You’re probably not getting enough sleep. We all know that groggy feeling that comes from staying up too late or getting up too early. Now scientists at UCLA know why: The brain’s neurons fire more slowly and with less power when we’re sleep deprived.

The researchers studied 12 epilepsy patients hospitalized ahead of surgery. As part of their treatment, the patients were forced to stay awake overnight while doctors monitored their brain activity through implanted electrodes. While the surgeons watched for signs of seizures, the sleep researchers showed the patients images and tracked their brain activity as they tried to identify each one. As the patients got sleepier, their response time slowed.

“We were fascinated to observe how sleep deprivation dampened brain cell activity,” said lead author Yuval Nir of Tel Aviv University. “Unlike the usual rapid reaction, the neurons responded slowly and fired more weakly, and their transmissions dragged on longer than usual.”

The researchers paid special attention to the temporal lobe, which controls visual perception and memory. The sluggish neurons had a hard time translating visual signals into conscious thought that led to action, which explains why tasks like driving can be so dangerous when we’re tired.

“Severe fatigue exerts a similar influence on the brain to drinking too much,” said Itzhak Fried, the study’s senior author and a professor of neurosurgery at the David Geffen School of Medicine at UCLA and Tel Aviv University.

The researchers also observed slow, sleep-like waves disrupting other brain activity, suggesting parts of the brain take catnaps when they get overtired. Those forced breaks cause the mental lapses we’re all too familiar with when we don’t get enough sleep.

The ability to function on as little sleep as possible has become a badge of honor in our productivity-obsessed, striving culture. Charles Darwin’s theory of evolution would argue we should be able to evolve to meet that “need” for more waking hours in every day. But the UCLA study reiterates the importance of a truth God gave us from the beginning: Rest is just as important as work. God didn’t design our bodies, or our brains, to function 24/7.

On the open road

It’s one short ride for a suburban Phoenix family, but a giant leap for driverless vehicles. Waymo, Google’s self-driving car company, announced this week plans to let test riders use its vehicles for everyday trips such as commutes, errands, and dropping off the kids at school.

Already, the company is testing self-driving Chrysler Pacifica minivans in the Phoenix area without backup drivers in the front seat. Waymo employees ride in the back and can push a button to bring the car to a stop in case of an emergency. The company said it chose Phoenix for the tests because of the temperate weather and easy-to-navigate streets.

Waymo is accepting applications for its early rider program, which will give residents access to self-driving vehicles they can summon with an app, similar to calling for an Uber ride. The company appears to be leading the pack of automakers and tech leaders racing to develop driverless cars, but others likely won’t be far behind, said expert Sam Abuelsamid of Navigant Research.

Intel CEO Brian Krzanich predicted driverless cars will be the norm in a few decades: “Given the pace at which autonomous driving is coming to life, I fully expect my children’s children will never have to drive a car.” —Lynde Langdon

Uncertain outcome

Scientists are warning users of cannabidiol, a chemical found in marijuana, that sellers of the unregulated drug often mislabel their products. Cannabidiol can help patients with seizures, anxiety, pain, and other health problems, and it doesn’t cause the characteristic “high” of marijuana because it doesn’t contain the chemical THC. Cannabidiol is legal in many states, but the federal government considers it a Schedule I controlled substance, and the Food and Drug Administration doesn’t oversee its production.

Researchers from Pennsylvania State University analyzed 84 different products and found 68 percent of them contained quite a bit more or less cannabidiol than their labels advertised. Only 30 percent of the products had cannabidiol content within 10 percent of the amount listed on the label.

Studies have not shown that too much of the chemical causes harm, but patients who take cannabidiol on a regular basis might not get consistent results because of the irregularities in its concentration, said Marcel Bonn-Miller, the study’s lead author. Bonn-Miller called for more regulation of the substance: “It’s crazy to have less oversight and information about a product being widely used for medicinal purposes, especially in very ill children, than a Hershey bar.” —L.L.