Much remains unknown about how the brain controls the tongue, given how its quick motions are difficult to track. Now, experiments show that the brain circuits in mice that help the tongue lick water may be the same ones that help primates reach out to grasp objects, scientists report in the journal Nature.
Using high-speed video, neuroscientist Tejapratap Bollu and colleagues recorded the sides and bottoms of mouse tongues as the rodents drank from a waterspout.
The researchers discovered that successful licks required previously unknown corrective movements, too fast to be seen in standard video, according to the German News Agency (dpa).
These adjustments came after the tongue missed unseen or distant droplets. Inhibiting a brain region that controls the body's voluntary motions impaired these corrections, suggesting this brain area was behind these movements.
These newfound corrective motions are similar to ones that primates use when reaching out with their limbs for uncertain targets, the researchers say. Those primate adjustments are also controlled by similar brain circuits as those used by the mice.
"This to me shows that mammalian brains use similar principles to control the tongue and the limb. Everything we know about reaching in the primates can also be used to understand how the brain controls tongue movements," says Bollu, at the Salk Institute for Biological Studies in La Jolla, California.
