Engage multiple layers to rebuild a brain
The researchers placed mice in a dark box and trained them to search for a nearby object with their whiskers. When the mice detected the object, they pulled a lever with their paw to dispense water as a reward. Conventional wisdom argued that this kind of detection task depends almost entirely on a functioning sensory cortex — in this case, the barrel cortex.
To confirm this was true, the researchers used laser light to temporarily turn off barrel-cortex cells, a popular technique known as optogenetics. As expected, animals had difficulty whisking while the cells were turned off. And when the team then permanently removed their barrel cortex, the animals could not perform the task the next day.
But on day two, the animals’ performance suddenly recovered to original levels. “This came as a huge surprise, since it suggested that tactile sensation, such as whisker-based touch, may not completely rely on the cortex,” said Dr. Hong. “These findings challenge the commonly held, cortex-centric view of how the brain drives touch perception.”