Alien Limbs

Coming soon… “The Leg from Outer Space!”

This is Sandra Tsing Loh with the Loh Down on Science, and Alien Limb Syndrome!

Patients with this condition describe feeling as if their arms and legs have a mind of their own. They’ll “scratch an itch” that doesn’t exist, or reach for something without realizing it. What gives?

Ryan Darby, at Vanderbilt University, has some ideas. Lesions, or damaged brain tissue, are common in people with this condition. What makes these lesions cause Alien Limb Syndrome specifically?

Darby and his team collected brain scans of patients with Alien Limb Syndrome. They overlapped the lesions onto maps of brain networks. Damaged networks centered around a specific area of the brain involved with voluntary movement. Darby now plans to study this brain region in more detail.

We still don’t know exactly HOW the condition causes some people’s limbs to have “free will.” But this study is a good first step in understanding how our brain makes decisions.

No need to worry about aliens just yet…let’s figure out how humans work first! And…where my right arm left the car keys!