But the biggest surprise, said Mehta, was that when they measured a rat's licking pattern in just an auditory world that is, one with no visual cues the rodent's tongue showed a clear map of space, as if the tongue knew where the food was.
"They demonstrated this by licking more in the vicinity of the reward. But their legs showed no sign of where the reward was, as the rats kept walking randomly without stopping near the reward," he said. "So for the first time, we showed how multisensory stimuli, such as lights and sounds, influence multimodal behavior, such as generating a mental map of space to navigate, and reward anticipation, in different ways. These are some of the most basic behaviors all animals engage in, but they had never been measured together."
Previously, Mehta said, it was thought that all stimuli would influence all behaviors more or less similarly.
"But to our great surprise, the legs sometimes do not seem to know what the tongue is doing," he said. "We see this as a fundamental and fascinating new insight about basic behaviors, walking and eating, and lends further insight toward understanding the brain mechanisms of learning and memory, and reward consumption."
|Contact: Mark Wheeler|
University of California - Los Angeles