Nir Grossman, Suhasa B. Kodandaramaiah and Andrii Rudenko.

Researchers have discovered a way to stimulate neurons deep within the brain without the invasive, implanted electrodes that physicians currently use to treat severe brain-related conditions like Parkinson's disease.

Current limitations: Implanted electrodes stimulate neurons in just one part of the brain and aren't helpful for other conditions (like stroke, traumatic brain injury or memory loss from Alzheimer's) that might benefit from much wider deep-brain stimulation that doesn't cause lasting damage to surrounding brain tissue.

What they did: Researchers from MIT sent two high-frequency electrical signals, which pass through the brain without exciting many neurons, from opposite sides of the brain in mice. They met in the middle, creating a new type of electrical wave that stimulated the neurons in a deep region of the brain.

Why it matters: Current non-invasive methods aren't able to work deep in the brain, which is where efforts to repair damage to neurons are most needed.

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Updated 1 hour ago - Health

World coronavirus updates

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

New Zealand confirmed Thursday there are now 13 local cases linked to the four who tested positive for COVID-19, ending 102 days with no community spread. Auckland locked down Wednesday for 72 hours and the rest of NZ is under lesser restrictions.

By the numbers: Over 749,400 people have died of the novel coronavirus globally and over 20.6 million have tested positive, per Johns Hopkins. More than 12.8 million have recovered from the virus.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Annelise Capossela/Axios

  1. Global: Total confirmed cases as of 3 a.m. ET: 20,624,316 — Total deaths: 749,421— Total recoveries: 12,831,800Map.
  2. U.S.: Total confirmed cases as of 3 a.m. ET: 5,197,147 — Total deaths: 166,027 — Total recoveries: 1,714,960 — Total tests: 63,252,257Map.
  3. Politics: Pelosi says Mnuchin told her White House is "not budging" on stimulus position.
  4. Business: U.S. already feeling effects of ending unemployment benefits.
  5. Public health: U.S. records deadliest coronavirus day of the summer — America's two-sided COVID-19 response
  6. Education: New Jersey governor allows schools to reopenGallup: America's confidence in public school system jumps to highest level since 2004.

Bob Woodward's new book details letters between Trump and Kim Jong-un

Bob Woodward during a 2019 event in Los Angele. Photo: Michael Kovac/Getty Images

Journalist Bob Woodward has obtained "25 personal letters exchanged" between President Trump and North Korean leader Kim Jong-un for his new book, "Rage," publisher Simon & Schuster revealed on Wednesday.

Details: In the letters, "Kim describes the bond between the two leaders as out of a 'fantasy film,' as the two leaders engage in an extraordinary diplomatic minuet," according to a description of the book posted on Amazon.