Two mathematicians have proved that a straightforward question—how hard is it to untie a knot?—has a complicated answer.

The birds grunt like tennis pros when generating their rat-a-tat, a performance strategy that may help stabilize core muscles.

Jiahe Zhang, PhD, of the Department of Psychiatry at Mass General Brigham, is the lead author of the paper published in Nature Neuroscience, "Cortical and subcortical mapping of the human ...