JUN 13, 2014 12:00 AM PDT

Penn Researchers Show How Human Learning Is Altered by Electrical Stimulation of Dopamine Neurons

WRITTEN BY: Ilene Schneider
Stimulation of a certain population of neurons within the brain can alter the learning process, according to a team of neuroscientists and neurosurgeons at the University of Pennsylvania. A report in the Journal of Neuroscience describes for the first time that human learning can be modified by stimulation of dopamine-containing neurons in a deep brain structure known as the substantia nigra. Researchers suggest that the stimulation may have altered learning by biasing individuals to repeat physical actions that resulted in reward.

"Stimulating the substantia nigra as participants received a reward led them to repeat the action that preceded the reward, suggesting that this brain region plays an important role in modulating action-based associative learning," said co-senior author Michael Kahana, PhD, professor of psychology in Penn's School of Arts and Sciences.

Eleven study participants underwent deep brain stimulation (DBS) treatment for Parkinson's disease. During an awakened portion of the procedure, participants played a computer game where they chose between pairs of objects that carried different reward rates (like choosing between rigged slot machines in a casino). The objects were displayed on a computer screen, and participants made selections by pressing buttons on hand-held controllers. When they got a reward, they were shown a green screen and heard a sound of a cash register (as they might in a casino). Participants were not told which objects were more likely to yield reward, but that their task was to figure out which ones were "good" options based on trial and error.

When stimulation was provided in the substantia nigra following reward, participants tended to repeat the button press that resulted in a reward. This was the case even when the rewarded object was no longer associated with that button press, resulting in poorer performance on the game when stimulation was given (48 percent accuracy), compared to when stimulation was not given (67 percent).

"While we've suspected, based on previous studies in animal models, that these dopaminergic neurons in the substainia nigra play an important role in reward learning, this is the first study to demonstrate in humans that electrical stimulation near these neurons can modify the learning process," said the study's co-senior author Gordon Baltuch, MD, PhD, professor of neurosurgery in the Perelman School of Medicine at the University of Pennsylvania. "This result also has possible clinical implications through modulating pathological reward-based learning, for conditions such as substance abuse or problem gambling, or enhancing the rehabilitation process in patients with neurological deficits."

The research team included lead study author Ashwin Ramayya, a neuroscience MD/PhD student at Penn, along with Amrit Misra from Drexel University. The study was supported by the National Institutes of Health (MH55687).
About the Author
  • Ilene Schneider is the owner of Schneider the Writer, a firm that provides communications for health care, high technology and service enterprises. Her specialties include public relations, media relations, advertising, journalistic writing, editing, grant writing and corporate creativity consulting services. Prior to starting her own business in 1985, Ilene was editor of the Cleveland edition of TV Guide, associate editor of School Product News (Penton Publishing) and senior public relations representative at Beckman Instruments, Inc. She was profiled in a book, How to Open and Operate a Home-Based Writing Business and listed in Who's Who of American Women, Who's Who in Advertising and Who's Who in Media and Communications. She was the recipient of the Women in Communications, Inc. Clarion Award in advertising. A graduate of the University of Pennsylvania, Ilene and her family have lived in Irvine, California, since 1978.
You May Also Like
MAR 07, 2020
Cannabis Sciences
MAR 07, 2020
Why Cannabis Makes Some Feel Good and Others Paranoid
Whether or not someone enjoys the effects of cannabis tends to depend on how it makes them feel. For example, although f ...
MAR 16, 2020
Cannabis Sciences
MAR 16, 2020
Cannabis Reduces ADHD Med Use in New Study
As the legalization of medical cannabis increases in the U.S. and around the globe, its effects on a variety of conditio ...
MAR 12, 2020
Drug Discovery & Development
MAR 12, 2020
Brain Stimulants Help with Focus
Drugs like Ritalin, Adderall and similar medications have been assumed by the public as fuels to help people focus. But, ...
APR 17, 2020
Neuroscience
APR 17, 2020
Anti Vaxxers More Paranoid than Average Person
Researchers from Texas Tech University have found that anti-vaxxers (those who deny the efficacy of vaccines) are more p ...
APR 19, 2020
Plants & Animals
APR 19, 2020
Flamingos Understand the Value of Friendship
Most of the time, wild flamingos are observed in massive flocks as opposed to hanging out on their own. It’s evide ...
MAY 13, 2020
Drug Discovery & Development
MAY 13, 2020
FDA Fast Tracks Vaccine for COVID-19
Biopharmaceutical company, Moderna, has announced that the US Food and Drug Administration has approved its experimental ...
Loading Comments...