Leaping, scurrying, flying and swimming through their natural habitats, animals compile a mental map of the world around them — one that they use to navigate home, find food and locate other points of vital interest. Neuroscientists have chiseled away at the problem of how animals do this for decades. A crucial piece of the solution is an elegant neural code that researchers uncovered by monitoring the brains of rats in laboratory settings. That landmark discovery was awarded a Nobel Prize in 2014, and many scientists think the code could be a key component of how the brain handles other abstract forms of information.
Yet lab animals in a box with a flat floor only need to navigate through two dimensions, and researchers are now finding that extending the lessons of that situation to the real world is full of challenges and pitfalls. In a pair of studies recently published in Nature and Nature Neuroscience, scientists working with bats and rats showed — to their surprise — that the brain encodes 3D spaces very differently from 2D ones, employing a mechanism that they are still struggling to describe and understand.
“We expected something else entirely,” said Nachum Ulanovsky, a neurobiologist at the Weizmann Institute of Science in Israel who led the work in Nature and has studied neural representations of 3D spaces for more than 10 years. “We had to reboot our thinking.” [Continue reading…]