(Press-News.org) In the brain, dopamine is involved in a number of processes that control the way we behave. If an action results in the substance being released, we are more likely to repeat the action. This applies to actions such as eating, sexual intercourse or winning a competition. However, the same also holds true when individuals take harmful narcotics. Scientists believe that mental illnesses such as schizophrenia can be linked to dopamine imbalances.
Learning signal
If an action leads to a better response than expected, the brain will temporarily release more dopamine. If the response is worse than expected, the brain momentarily stops releasing dopamine. This mechanism is responsible for our tendency to repeat actions that have given us a high level of dopamine, and to avoid those that result in lower dopamine levels.
"That's why many see dopamine as a learning signal," according to post doctorate Jakob Kisbye Dreyer of the Department of Neuroscience and Pharmacology, University of Copenhagen, who was involved with the module's creation.
"Others have argued that it is impossible for the dopamine system to react quickly enough to be a part of our learning process. It can take a split second to learn something, but a cell that releases dopamine works slowly. If you look at a lighthouse that flashes at a slow frequency, you might not notice right away that the light was turned off. Likewise, the arguments against dopamine as an aid to learning have focused on the slow feedback time when you experience something bad, and that it is too slow for the brain to make a connection. Our model shows that the collective signal from many cells provides a rapid enough reaction to influence learning."
Mathematic approach to the brain
One of the biggest challenges faced by neurologists is that it is difficult to study active brains in living humans.
"Theoretical neuroscience can easily become very complicated," Dreyer says. "If we try to come up with complete explanations of the way the brain works, we get models that are so complex that they are difficult to test."
The dopamine model's predictions, created as part of a unique collaborative effort among physicists, mathematicians and neurobiologists, are supported by observations made in animal models.
"Different branches of natural science have surprisingly different ways of thinking," Dreyer says. "Our work – and our model – is only possible because even though I am a physicist, I have been able to conduct research at the Department of Neuroscience and Pharmacology at the Faculty of Health Sciences. As soon as we are certain that the model is correct, we can begin applying it to dopamine-related illnesses such as drug addiction and schizophrenia."
The team's dopamine model will be described in the cover article of the next issue of Journal of Neuroscience, to be released at on 20 October. The article was written by Jakob Dreyer, Rune Berg and Jørn Hounsgaard, all of the Department of Neuroscience and Pharmacology, together with Kjartan Herrik of Lundbeck's Department of Neurophysiology.
INFORMATION: END
Over the last few decades, the dramatic rise in pediatric obesity rates has emerged as a public health threat requiring urgent attention. The responsibility of identifying and treating eating and weight-related problems early in children and adolescents falls to health care providers and other professionals who work with the child, according to Professor Denise Wilfley and colleagues from the Department of Psychiatry at Washington University School of Medicine in the US. Furthermore, the key to successful treatment is a team effort involving providers and parents.
Wilfley's ...
BUFFALO, N.Y. -- Results of a new Women's Health Initiative (WHI) report show that hormone therapy is associated with an increased the risk of death from breast cancer, as well as an increased risk of developing invasive breast cancer in postmenopausal women.
Jean Wactawski-Wende, PhD, professor of social and preventive medicine at the University at Buffalo and one of the primary authors on the paper, published today in JAMA, says the breast cancers found in these women also tended to have more lymph node involvement, indicating a poorer prognosis.
"This report, which ...
WASHINGTON — Motherhood may actually cause the brain to grow, not turn it into mush, as some have claimed. Exploratory research published by the American Psychological Association found that the brains of new mothers bulked up in areas linked to motivation and behavior, and that mothers who gushed the most about their babies showed the greatest growth in key parts of the mid-brain.
Led by neuroscientist Pilyoung Kim, PhD, now with the National Institute of Mental Health, the authors speculated that hormonal changes right after birth, including increases in estrogen, ...
Montreal, October 20, 2010 – Daily sleeping and eating patterns are critical to human well-being and health. Now, a new study from Concordia University has demonstrated how the brain chemical dopamine regulates these cycles by altering the activity of the "clock-protein" PER2. Published in the Journal of Neuroscience, these findings may have implications for individuals with Parkinson's Disease with disrupted 24-hour rhythms of activity and sleep.
"PER2 is a protein well-known for its role in the regulation of daily or circadian rhythms, this is why it is referred to ...
The UK's National Physical Laboratory (NPL) is working to provide more reliable measurement of the electrical properties of materials used in nanotechnology – which could lead to much more accurate devices in the future.
Scanning probe microscopy (SPM) won the Nobel Prize in 1986. It uses a nano-sized probe to feel the surface of a material – akin to a finger reading Braille on an extremely small scale. The technique can also measure the electrical properties of materials used in nanotechnology – and "feel" how the materials react when electricity is passed through it. ...
CAMBRIDGE, Mass., Oct. 20, 2010 -- Microbes living at the bottom of the Gulf of Mexico may consume far more of the gaseous waste from the Deepwater Horizon oil spill than previously thought, according to research carried out within 100 miles of the spill site.
A paper on that research, conducted before the Deepwater Horizon rig exploded six months ago today, will appear in a forthcoming issue of the journal Deep-Sea Research II. It describes the anaerobic oxidation of methane, a key component of the Gulf oil spill, by microbes living in seafloor brine pools.
"Because ...
CHAMPAIGN, lll. — After the campus shootings at Virginia Tech in 2007 and Northern Illinois University in 2008, hundreds of affected students turned to social media websites to share their grief and search for solace. A new study of these students found that their online activities neither helped nor harmed their long-term psychological health.
The study, which appears in Personality and Social Psychology Bulletin, gives a first-of-its-kind portrait of student reactions to shootings on their campuses. It also documents the (online and off-line) activities they engaged ...
For the first time, researchers have discovered a disease mechanism that links hereditary amyotrophic lateral sclerosis to the more common "sporadic" form of ALS -- and points to a possible therapeutic target.
The findings are reported online in advance of publication in the journal Nature Neuroscience.
ALS is an adult-onset disease that causes progressive degeneration of motor neurons and death within three to five years of diagnosis.
Scott Brady, professor and head of anatomy and cell biology at the University of Illinois at Chicago College of Medicine, studies ...
BOSTON––Raising the survival rate of children with sarcoma in low-income countries will require steps to diagnose the disease sooner, train cancer pathologists, expand radiation therapy services, create multi-specialty teams to review each case, and other actions, according to an international study led by Dana-Farber/Children's Hospital Cancer Center researchers. The findings will be presented at the 42nd Congress of the International Society of Paediatric Oncology (SIOP) in Boston on Friday, Oct. 22.
The study explored why, despite advances in the treatment of pediatric ...
So disease-causing bacteria in the body finally have multiplied to the point where their numbers are large enough to cause illness. What's next? They get out their "smart phones" and whisper "Let's roll!" That's how an article in ACS' monthly Chemical Reviews describes the substances — "smart phones of the microbial world" — that bacteria use to transmit chemical signals that launch infections and monitor their environment. The authors describe progress toward understanding and blocking this biochemical chitchat, a development that could lead to new treatments for the growing ...
