General Health

General health issues, Medical conditions, Research and studies and more

Mental Health

Natural Medicine

Nutritional supplements, Herbs, Alternative medicine and more…

Wellness & Lifestyle

Nutrition, Diets, Healthy living, Detox, Exercise and Physical Fitness, Sports Fitness and more…

Women’s Health

Relationships, Pregnancy, Birth control, Menopause and more

Home » Information, News

Clues to addiction.

Article / Review by on January 18, 2012 – 10:40 pmNo Comments

Clues to addiction
Research showing how neurons interact could lead to new treatments

Naoshige Uchida (above) and colleagues report in the Jan. 18 issue of Nature that reward prediction error is actually the product of a complex interplay between two classes of neurons — one that relies on dopamine and an inhibitory class of neurons that uses the neurotransmitter GABA./ Jon Chase/ Harvard Staff PhotographerNaoshige Uchida (above) and colleagues report in the Jan. 18 issue of Nature that reward prediction error is actually the product of a complex interplay between two classes of neurons — one that relies on dopamine and an inhibitory class of neurons that uses the neurotransmitter GABA./ Jon Chase/ Harvard Staff Photographer

Harvard scientists have developed the fullest picture yet of how neurons in the brain interact to reinforce behaviors ranging from learning to drug use, a finding that might open the door to new treatments for addiction.

The finding is the result of a yearlong effort by a team of researchers led by Naoshige Uchida, associate professor of molecular and cellular biology, to examine a brain process known as reward prediction error. Thought to be a key component of learning, prediction error has long been considered the product of dopamine neurons firing in response to an unexpected “reward,” thus reinforcing the behavior that led to the reward.

But Uchida and colleagues from Harvard and Beth Israel Deaconess Medical Center report in the Jan. 18 issue of Nature that reward prediction error is actually the product of a complex interplay between two classes of neurons — one that relies on dopamine and an inhibitory class of neurons that uses the neurotransmitter GABA.

“Until now, no one knew how these GABA neurons were involved in the reward and punishment cycle,” Uchida said. “What we believe is happening is that they are inhibiting the dopamine neurons, so the two are working together to make the reward error computation.”

Before Uchida and his team could prove that GABA neurons were involved in the computation, however, they had to be sure what type of cells they were observing.

The challenge in studying both dopamine and GABA neurons is that the two cell types are intermingled in a relatively small area of the brain, making it difficult for researchers to definitively know which type they are observing. Ultimately, researchers developed an elegant solution to the problem.

Researchers genetically altered the neurons in two groups of mice — one for the dopamine neurons, the other for GABA neurons — to fire when hit by a pulse of laser light. Once researchers were certain they were measuring the correct type of neuron, they used electrodes to measure whether and when the neurons fired in response to expected and actual rewards.

The results, Uchida said, showed that while firing of dopamine neurons signaled reward prediction error, firing of GABA neurons signaled an expected reward. Taken together, GABA neurons help dopamine neurons calculate reward prediction error.

The finding is particularly important, Uchida said, because it sheds new light on how behaviors can be reinforced, either through normal brain function, or by damaging the way the two types of neurons interact.

“What happens with drug abuse is that many drugs, such as opioids andcannabinoids, target the GABA neurons,” he said. “What we are hypothesizing is that, by inhibiting those GABA neurons, you can lose this feedback cycle, so you keep getting reinforcing signals from the dopamine neurons.

“This is a new way of thinking about addiction in general,” Uchida continued. “Based on this theory, I believe you may be able to develop new theories or treatments for addiction.”

By Peter Reuell
Harvard Staff Writer

###

About Harvard Medical School (HMS)

Driving Change. Building Momentum. Making History. 

“Since 1872, Harvard Medical School has been the incubator of bold ideas—a place where extraordinary people advance education, science and health care with unrelenting passion.

Whether training tomorrow’s doctors and scientists, decoding the fundamental nature of life, advancing patient care or improving health delivery systems around the world, we are never at rest. Allied with some of the world’s best hospitals, research institutes and a University synonymous with excellence, the School’s mission remains as ambitious as it is honorable: to alleviate human suffering caused by disease.”

More at Harvard Medical School & Harvard Medical School. Generations of Leaders.

Harvard Medical School. Medicinezine.com Harvard Medical School (HMS) logo

_________________________________________________

###

About Harvard School of Public Health (HSPH)

Harvard School of Public Health is dedicated to advancing the public’s health through learning, discovery and communication. More than 400 faculty members are engaged in teaching and training the 1,000-plus student body in a broad spectrum of disciplines crucial to the health and well being of individuals and populations around the world. Programs and projects range from the molecular biology of AIDS vaccines to the epidemiology of cancer; from risk analysis to violence prevention; from maternal and children’s health to quality of care measurement; from health care management to international health and human rights.

More at Harvard School of Public Health (HSPH) & Harvard School of Public Health (HSPH). History.

Medicinezine.com Harvard School of Public Health (HSPH) Logo 540 ok

_________________________________________________

###

About Harvard University.

Established in 1636, Harvard is the oldest institution of higher education in the United States. The University, which is based in Cambridge and Boston, Massachusetts, has an enrollment of over 20,000 degree candidates, including undergraduate, graduate, and professional students. Harvard has more than 360,000 alumni around the world.

Harvard University is devoted to excellence in teaching, learning, and research, and to developing leaders in many disciplines who make a difference globally. Harvard faculty are engaged with teaching and research to push the boundaries of human knowledge. For students who are excited to investigate the biggest issues of the 21st century, Harvard offers an unparalleled student experience and a generous financial aid program, with over $160 million awarded to more than 60% of our undergraduate students. The University has twelve degree-granting Schools in addition to the Radcliffe Institute for Advanced Study, offering a truly global education.

‘Universities nurture the hopes of the world: in solving challenges that cross borders; in unlocking and harnessing new knowledge; in building cultural and political understanding; and in modeling environments that promote dialogue and debate… The ideal and breadth of liberal education that embraces the humanities and arts as well as the social and natural sciences is at the core of Harvard’s philosophy. ’/ Drew Gilpin Faust

More About Harvard University & About Harvard University. Information.

###

*  The above story is adapted from materials provided by Harvard University

_________________________________________________________________

Medicinezine.com Harvard University Logo

Tags: , , , , , , , ,

Leave a comment!

Add your comment below, or trackback from your own site. You can also subscribe to these comments via RSS.

Be nice. Keep it clean. Stay on topic. No spam.

You can use these tags:
<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

Notify me of followup comments via e-mail. You can also subscribe without commenting.