To survive, animals must explore their world to find the necessities of life. It's a complex task, requiring them to form them a mental map of their environment to navigate the safest and fastest routes to food and water. They also learn to anticipate when and where certain important events, such as finding a meal, will occur.
Understanding the connection between these two fundamental behaviors, navigation and the anticipation of a reward, had long eluded scientists because it was not possible to simultaneously study both while an animal was moving.
In an effort to overcome this difficulty and to understand how the brain processes the environmental cues available to it and whether various regions of the brain cooperate in this task, scientists at UCLA created a multisensory virtual-reality environment through which rats could navigate on a trac ball in order to find a reward. This virtual world, which included both visual and auditory cues, gave the rats the illusion of actually moving through space and also allowed the scientists to manipulate the cues.
The results of their study, published in the current edition of the journal PLOS ONE, revealed something "fascinating," said UCLA neurophysicist Mayank Mehta, the senior author of the research.
The scientists found that the rats, despite being nocturnal, preferred to navigate to a food reward using only visual cues they ignored auditory cues. Further, with the visual cues, their legs worked in perfect harmony with their anticipation of food; they learned to efficiently navigate to the spot in the virtual environment where the reward would be offered, and as they approached and entered that area, their licking behavior a sign of reward anticipation increased significantly.
But take away the visual cues and give them only sounds to navigate, and the rats legs became "lost"; they showed no sign they could navigate directly to the reward and ins
|Contact: Mark Wheeler|
University of California - Los Angeles