Our brains get confused when we're anxious

Competing neurons in this part of the brain help us make decisions, such as choosing words. (Credit: Image courtesy of Marie Banich)

A new University of Colorado at Boulder study sheds light on the brain mechanisms that allow us to make choices and ultimately could be helpful in improving treatments for the millions of people who suffer from the effects of anxiety disorders.

In the study, CU-Boulder psychology Professor Yuko Munakata and her research colleagues found that "neural inhibition," a process that occurs when one nerve cell suppresses activity in another, is a critical aspect in our ability to make choices.

"The breakthrough here is that this helps us clarify the question of what is happening in the brain when we make choices, like when we choose our words," Munakata said.

"Understanding more about how we make choices, how the brain is doing this and what the mechanisms are, could allow scientists to develop new treatments for things such as anxiety disorders."

Researchers have long struggled to determine why people with anxiety can be paralyzed when it comes to decision-making involving many potential options.

Munakata believes the reason is that people with anxiety have decreased neural inhibition in their brain, which leads to difficulty making choices.

"A lot of the pieces have been there," she said. "What's new in this work is bringing all of this together to say here's how we can fit all of these pieces of information together in a coherent framework explaining why it's especially hard for people with anxiety to make decisions and why it links to neural inhibitors."

A paper on the findings appeared in the Aug. 30 Proceedings of the National Academy of Sciences.

CU-Boulder professors Tim Curran, Marie Banich and Randall O'Reilly, graduate students Hannah Snyder and Erika Nyhus and undergraduate honors thesis student Natalie Hutchison co-authored the paper.

In the study, they tested the idea that neural inhibition in the brain plays a big role in decision-making by creating a computer model of the brain called a neural network simulation.

"We found that if we increased the amount of inhibition in this simulated brain then our system got much better at making hard choices," said Hannah Snyder, a psychology graduate student who worked with Munakata on the study.

"If we decreased inhibition in the brain, then the simulation had much more trouble making choices."

Through their model they looked at the brain mechanisms involved when we choose words. They then tested the model's predictions on people by asking them to think of the first verb that comes to mind when they are presented with a noun.

Beruli Ulcers: The WHO Needs to seriously re-think it's strategy

Buruli ulcers, one of the ‘neglected tropical diseases’ left aside by big pharma and governments alike, are reasonably well treatable, also in poor regions but then more attention has to be paid to early diagnosis and correct treatment.

This means the rules of the World Health Organization urgently need to be changed. So say scientists of the Antwerp Institute of Tropical Medicine (ITM), based on ten years of research in Congo.

The disease is caused by Mycobacterium ulcerans, a nephew of the infamous tuberculosis bacterium. It occurs in tropical and subtropical countries, mainly in Africa. It causes hideously ulcerating ‘holes’ in the skin, that can dig to the bone and can outgrow to diameters of more than 10 centimetres.

Much about the disease is unknown, for instance how exactly people get infected. It is assumed that water plays a role, but only in 2008 scientists — at ITM — succeeded in cultivating the bacterium from a water insect.

For a long time the only treatment consisted of caring for the wounds, and possibly a skin transplantation. Nowadays the WHO proposes a treatment analogous to tuberculosis, with two antibiotics, rifampicin and streptomycin. This works for light cases, but for lesions above 10 cm the effect was not documented.

ITM scientist Anatole Kibadi Kapay collected cases in DR Congo from the previous five years, when surgery combined with antibiotics was used, and from the five year before that, when only surgery was used. In the process he discovered a new focus close to the Angolan border; he assumes it to be correlated to the working conditions in the illegal diamond mines there.

Kibadi Kapay noticed that the WHO guidelines for clinical diagnosis lead to a correct diagnosis in only 2 cases out of 3. As opposed to a Ziehl-Neelsen smear, a microscopic technique that is within reach of poor countries — and that, through a better diagnosis, prevents the needless use of antibiotics.

But when large wounds have to be treated, from a microscopically confirmed Buruli case, antibiotics indeed are of good use. With surgery only, 15% of patients relapse; with parallel use of antibiotics, less than 2% relapse. But antibiotics only, without surgery, make large wounds worse.

Kibadi Kapay — who today received a doctorate from Antwerp University for his work — and his ITM colleagues advocate faster surgery of large ulcerating lesions, without four weeks of waiting with antibiotics only.

The more because patients themselves already wait a long time before consulting a doctor — to them the ulcers are inflicted by witchcraft or fate.

The research by Kibadi Kapay demonstrates the need of a better education of the population, but more important, it shows that WHO guidelines for diagnosis and treatment of Buruli ulcers urgently need to be adapted.