AUSTIN, Texas — Babies’ stroke-damaged brains can pull a mirror trick to recover.

A stroke on the left side of the brain often damages important language-processing areas. But people who have this stroke just before or after birth recover their language abilities in the mirror image spot on the right side, a study of teens and young adults shows. Those patients all had normal language skills, even though as much as half of their brain had withered away, researchers reported February 17 at the annual meeting of the American Association for the Advancement of Science.
Researchers so far have recruited 12 people ages 12 to 25 who had each experienced a stroke to the same region of their brain’s left hemisphere just before or after birth. People who have this type of stroke as adults often lose their ability to use and understand language, said study coauthor Elissa Newport, a neurology researcher at Georgetown University Medical Center in Washington, D.C.

MRI scans of healthy siblings of the stroke patients showed activity in language centers in the left hemisphere of the brain when the participants heard speech. The stroke patients showed activity in the exact same areas — just on the opposite side of the brain.

It’s well established that if an area of the brain gets damaged, other brain areas will sometimes compensate. But the new finding suggests that while young brains have an extraordinary capacity to recover, there might be limits on which areas can pinch-hit.

“When you look at a very well-defined population, recovery takes place in a very particular set of regions,” said Newport. Young children usually show language activity in the same areas on both sides of their brain, Newport noted, and the left side becomes more dominant over time. But in the case of a major stroke to the left side, the corresponding areas on the right side of the brain might already be primed to take over.

Two newly discovered giant viruses have the most comprehensive toolkit for assembling proteins found in any known virus. In a host cell, the viruses have the enzymes needed to wrangle all 20 standard amino acids, the building blocks of life.

Researchers dubbed the viruses Tupanvirus deep ocean and Tupanvirus soda lake, combining the name of the indigenous South American god of thunder, Tupan, with the extreme environment where each type of virus was found. The giant viruses are among the largest of their kind — up to 2.3 micrometers in length — which is about 23 times as long as a particle of HIV, the scientists report February 27 in Nature Communications.
Tupanviruses can infect a wide range of hosts, such as protists and amoebas, but pose no threat to humans, the researchers say.

Viruses are considered nonliving, but the genetic complexity of giant viruses has some scientists questioning that categorization. Each Tupanvirus, for example, has a massive genetic instruction book with roughly 1.5 million base pairs of DNA, more than what some bacteria have, says coauthor Bernard La Scola, a virologist at Aix-Marseille University in France.

But other scientists say giant viruses aren’t so different from their smaller kin. Research by Frederik Schulz, with the Department of Energy Joint Genome Institute in Walnut Creek, Calif., suggests these microscopic behemoths are regular viruses that acquired extra genes from hosts and should not be classified as life.

Tupanviruses don’t settle the controversy, but they do challenge our preconceptions of what life is, La Scola says.