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Bees, Brains and Addiction

By Sherry Seethaler I April 25, 2005

To understand the complex processes in the human brain that lead to addiction, some researchers at UCSD have turned to bees.  

A bee learns to land on a tile of a certain color after it is
rewarded just once with sugar water for landing on that color.
Credit: James Nieh, UCSD

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.  

"We have learned more
about the brain in the last 10 years than in all of human history," said Sejnowski at the beginning of his talk.

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.  

Humans, rats and other vertebrates share a region of
the brain that plays a key role in addictive behavior.
Credit: Samar B. Metha, UCSD

His discovery is one of many that renowned neuroscientists in La Jolla have conveyed in non-technical language to students, teachers and other non-scientists in San Diego through a neuroscience educational outreach program called "Grey Matters," initiated last fall by UCSD's Division of Biological Sciences and funded by Amylin Pharmaceuticals.  

The program includes a monthly lay language lecture by a local neuroscientist on a topic of broad public interest, televised broadcasts of that lecture locally and nationally by UCSD-TV and a corresponding educational Web site with information and lessons for students, teachers and anyone else interested in neuroscience topics. Among the participants at last week's lecture were 20 students from San Diego's High Tech High, seeking to learn more about the neurobiology of drugs and addiction for their science class.  

The next lecture in the series will be given May 24 by Ralph Greenspan of the Neurosciences Institute on "Sleep, Waking and Arousal." For more information on this lecture and the Grey Matters series, see: http://greymatters.ucsd.edu/  

The Grey Matters educational website for students, teachers and the public can be accessed at: http://www.ucsd.tv/greymatters/

In addition to the scheduled UCSD-TV broadcasts of Grey Matters lectures on local cable channels, (schedule at: http://www.ucsd.tv/greymatters/tvschedule.asp) full-length presentations are also available online in streaming video at: http://www.ucsd.tv/greymatters/archives.asp

 

 

 


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