Doris Tsao / Caltech

Researchers believe they've cracked the code for how primates are able to recognize faces. And, it may be relatively simple: only 200 neurons or so in the brain appear to be responsible for the ability of macaque monkeys to identify the faces of humans that they know over those of complete strangers.

Why it matters: Humans and other primates are thought to use a similar face recognition system, so understanding how images are encoded by the neurons could inform the development of artificial vision.

The question: Researchers had previously identified six parts of the brain (in a place called the inferior temporal cortex) that were responsible for identifying faces. Specific nerve cells in these six regions of the brain respond more strongly when we see faces compared to objects. What scientists didn't know was the exact combination of these "face cells" required to identify those we know from strangers.

The study: Researchers inserted electrodes into the brains of macaque monkeys in the six regions. They then mapped various features of faces (like the distance between eyes) onto a grid and used them to create 2000 photos of manipulated human faces. When they were shown to the monkeys, just 205 neurons from two of the six regions where "face cells" exist activated. Using the pattern of neuron activation, the researchers were then able to reconstruct the faces the monkey was looking at.

Fun quote: "People always say a picture is worth a thousand words. But I like to say that a picture of a face is worth about 200 neurons." —Doris Tsao, professor of biology and biological engineering at the California Institute of Technology.

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Updated 2 hours ago - World

Pandemic plunges U.K. into "largest recession on record"

The scene near the Royal Exchange and the Bank of England in the City of London, England. Photo: Tolga Akmen/AFP via Getty Images

The United Kingdom slumped into recession as its gross domestic product GDP shrank 20.4% compared with the first three months of the year, the Office of National Statistics (ONS) confirmed Wednesday.

Why it matters: Per an ONS statement, "It is clear that the U.K. is in the largest recession on record." The U.K. has faired worse than any other major European economy from coronavirus lockdowns, Bloomberg notes. And finance minister Rishi Sunak warns the situation is likely to worsen.

Updated 2 hours ago - Health

World coronavirus updates

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Axios Visuals

The United Kingdom slumped into recession on Wednesday, as its gross domestic product GDP shrank 20.4% compared with the first three months of the year.

By the numbers: Over 741,400 people have died of the novel coronavirus globally and more than 20.2 million have tested positive, per Johns Hopkins. Almost 12.6 million have recovered from the virus.

Updated 3 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Annelise Capossela/Axios

  1. Global: Total confirmed cases as of 3 a.m. ET: 20,294,091 — Total deaths: 741,420— Total recoveries: 12,591,454Map.
  2. U.S.: Total confirmed cases as of 3 a.m. ET: 5,141,207 — Total deaths: 164,537 — Total recoveries: 1,714,960 — Total tests: 63,252,257Map.
  3. States: Georgia reports 137 coronavirus deaths, setting new daily record Florida reports another daily record for deaths.
  4. Health care: Trump administration buys 100 million doses of Moderna's coronavirus vaccine.
  5. Business: Moderna reveals it may not hold patent rights for vaccine.
  6. Sports: Big Ten scraps fall football season.
  7. World: Anthony Fauci "seriously" doubts Russia's coronavirus vaccine is safe