It’s been hot in London this week. Really hot. A dangerous heat wave has hit Western Europe. On Wednesday, the UK recorded its highest ever June temperature at 36.1 °C (about 97 °F). But as the weather app on my phone confirmed, it felt like 39 °C.

Much of Western Europe is suffering, bringing awful consequences for agriculture, infrastructure, and the health system. But heat can also affect the brain.

Studies have confirmed that as temperatures rise, people seem to get more irritable and more violent. And they have shown that firefighters find it harder to focus immediately after heat exposure. Rising temperatures can also have particularly disastrous outcomes for children and people with mental health disorders.

Research on lab animals suggests that excessive heat can alter the function of chemical signals in our brains. But we still need a better understanding of the mechanisms behind these effects.

Here’s what scientists are learning about extreme heat’s impact on the brain.

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For more on Europe’s heat wave, read our stories on why soaring temperatures are shutting down power plants and what they mean for the grid.

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Quote of the day

“The most advanced AI is built by a handful of American companies, on American soil, under American law, and what the rest of us are permitted to do with it can change on a Friday afternoon.”

—Nathan Benaich, AI investor at London-based venture firm Air Street Capital, tells the Financial Times about the geopolitical reality of US AI dominance.

One More Thing

MAX-O-MATIC

How technology helped archaeologists dig deeper

In 1991, construction workers in Manhattan unearthed hundreds of coffins. Further investigation revealed that the remains were between 200 and 300 years old, and they were all African and African American.

This discovery came at an inflection point in scientific history. Breakthroughs in chemical and genetic analysis allowed researchers to figure out where many of these people were born, the physical challenges they faced, and even the routes they took from Africa to North America.

Today, archaeologists are using techniques they could only dream of then: lasers, 3D photography, lidar, satellite imagery, and more. These tools are revealing where people came from, how ancient cities were built, and the lives of those who built them.