eLife 2018; 7:e29053

Recording electrical signals via implanted electrodes helps researchers understand what’s going on in the brain. Rodents have been set free with their implants, allowing brain activity to be recorded in unrestrained subjects. Bats are now being set loose too.

Cynthia Moss and colleagues at Johns Hopkins were interested in how the midbrain superior colliculus (SC) contributes to spatial orientation. They’ve looked at this before in bats, but not while the animals were freely flying. In their latest paper, they combine neural activity data from wireless electrodes implanted into the SC with audiovisual recordings and a novel echo model to tease apart how big brown bats determined their position while navigating an obstacle-filled space. Though they only observed two bats, the researchers saw dynamic changes in neuron activity as the bats echolocated their way through the room.