Soft spot for you

A mother’s love is not easily broken, and new research may help explain why. Physiological changes that take place during pregnancy may produce long-term changes in a mother’s brain that enhance her ability to bond with her baby, according to a study published in the journal Nature Neuroscience on Dec. 19.

Researchers at Leiden University in the Netherlands performed brain scans on a group of women trying to get pregnant for the first time. Twenty-five of the women became pregnant, and the researchers re-scanned them shortly after they gave birth. The mothers’ brains showed shrinkage in some areas associated with social attachment and empathy. In fact, the researchers were able to identify which women had become pregnant simply by tracking brain changes.

In addition, the same areas of the brain became more active on MRI scans when the mothers looked at pictures of their own babies—but not when they viewed photos of other infants.

The brain changes could benefit the mother by “strengthening her ability to read the needs of her relatively helpless infant,” Elseline Hoekzema, one of the researchers, told New Scientist.

The shrinking of certain areas in the mothers’ brains probably indicates changes designed to make the brain function more efficiently. “It’s unlikely these women are losing brain cells,” researcher Kirstie Whitaker at the University of Cambridge also told New Scientist, explaining that the phenomenon is likely similar to a pruning process she has seen in teenage brains as they mature.

A follow-up scan of the mothers in the study showed that the brain changes were still present two years later.

Natanael Pohan/SIPA via AP

Sun show

U.S. sky watchers are in for a big treat this summer. On Aug. 21 a total solar eclipse—where the moon moves in front of the sun—will darken skies all the way from Oregon to South Carolina, along a stretch of land about 70 miles wide. It will be the first total solar eclipse visible from the continental United States in nearly four decades and the first to sweep across the entire country since 1918, according to NASA. —J.B.

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Dental elixir

Good news for those who hate the squeal of the dentist’s drill: Dental fillings may one day be a thing of the past. In a study published Jan. 9 in Scientific Reports, researchers from King’s College London showed how they stimulated stem cells to fill in cracks and cavities in teeth.

When a tooth loses some of its dentin, the hard, bony tissue beneath the enamel that forms the bulk of the tooth, stem cells in the tooth’s pulp get busy manufacturing new dentin. But dentists still have to fill or seal the tooth to prevent further decay because stem cells can normally only repair small amounts of the tissue.

The King’s College researchers found that a group of molecules called glycogen synthase kinase inhibitors can supercharge the stem cells’ ability to stimulate dentin production. The scientists drilled tiny holes into the molars of mice to expose the pulp, inserted collagen sponges soaked in the inhibitors, and waited.

Six weeks later, they found the sponges had dissolved and the lost dentin was mostly regenerated.

So far the researchers have only used the process with mice, but the technique is simple, and one version of the tooth-repairing inhibitors has already passed human safety testing. They hope the technique will quickly progress to human clinical trials. —J.B.