To understand the complex processes in the human brain that lead to addiction, some researchers at UCSD have turned to bees.
Granted, the brains of humans and bees don’t look much alike. But how bees respond to simple rewards, such as food, can tell scientists much about the workings of the primitive portion of our brains that lead some of us to become addicted to tobacco, alcohol or other drugs.This region of the brain exerts such a powerful influence on the behavior of humans and other animals that a rat will work so tirelessly when it is rewarded with electrical stimulation to this region of the brain that it can forgo eating and ultimately starve to death.The neurobiology and evolutionary basis of the brain circuitry that processes information about rewards is the focus of study by Terrence Sejnowski, a professor of biology at both the Salk Institute and UCSD. He told a gathering of scientists, high school students and community members last week that neurobiologists like himself are gaining a better understanding of human addiction by examining simpler brains, such as those of bees.Bees learn to land on a tile of a certain color after they are rewarded just once with sugar water for landing on that color. A single nerve cell in a bee’s brain, Sejnowski explains, is responsible for deciding if the information coming from the senses predicts the sugar reward and signaling to the muscles to take the appropriate action to receive the reward.Computer models of how a bee assimilates and responds to information about a reward can be then applied to studies of how humans make decisions about rewards. And predictions from computer modeling of the bee brain can be tested via human brain imagining studies. For example, Sejnowski said that by using functional magnetic resonance imaging, which measures blood flow to reveal which regions of the brain are active, researchers in his laboratory have discovered that our brains process information about rewards differently if a reward is granted immediately for a simple behavior or if a person must work to receive the reward.(Source: University Of California – San Diego: May 2005.)