Keva Gaston
If Tiffanie Markus has her way, severe anxiety disorders can be treated with a little tinkering of the brain.
Markus, a doctoral student in psychology, is collaborating with Robert Jensen, professor of psychology and research adviser, on researching the use of the vagus nerve as a way of reducing anxiety.
She started the project because previous research was done on stimulation focusing on the left branch of the vagus nerve. This research is different from previous studies because it focuses on stimulating the right branch of the vagus nerve that comes in contact with the heart.
"A report came out about patients receiving vagus nerve stimulation for epilepsy and were also showing an improvement in mood, so I wanted to look at something in that direction," Markus said. "I looked into the literature and what I was finding was that it was not so much that people were less depressed, but there may be some connection to anxiety."
The vagus nerve comprises two nerves that start and exit the brain stem and goes down both sides of the neck running along the carotid arteries through the abdomen, sending feelers out to all the internal organs. It carries messages about the body's psychological state up to the brain. Markus said vagus comes from the Latin word for "wanderer" because the vagus nerve seems to wander around the body and connects to everything.
"We're thinking by changing the heart rate and respiration rate through the vagus nerve stimulation, we're changing the peripheral state which then changes the feedback that goes to your brain," Markus said. "Then you interpret your feelings from your peripheral state, thus creating less anxiety in the animal."
Markus performs her research in Jensen's laboratory and uses three techniques for the study. The first one is the open-field box designed to measure the lab rat's behavior. They measure time spent in the open space and time spent in safe perimeters of the box. If the rats spends time in the open areas of the box, it indicates less anxiety.
The second technique is an elevated-plus maze, which is made up of two enclosed arms and an open arm extended from it. Like the other technique, the time the rat spends on the open area indicates less anxiety.
The third technique is the predatory scent, which is a box with a cat collar dangling into it. The collar has the cat's scent on it and the rats are placed in the box. Because the scented collar heightens anxiety in rats, Markus observes how much time the rat spends adjacent to the collar and how much time the rat spends in the hide box or the safe dark area of the box.
"This study is part of a large scale investigation of the role the vagus nerve plays in modulating emotions and learning and memory recovery functions after brain damage," Jensen said.
The project is largely funded by the SIUC Psychology Department and Markus received some funding from the National Science Foundation in the form of a grant in which Jensen is the principal investigator of the organization.
The research is a follow-up to Jensen and Smith's study on how electrical stimulation of the vagus nerve can improve memory and learning in humans and can help lab rats recover much more quickly from brain injury. In August 2000, Jensen and Smith, along with an SIUC physiologist, a neurologist, a former SIUC graduate student and a representative from Houston-based Cyberonics Inc., were issued a patent for methods of using an electrical nerve implant to improve memory and learning.
Markus said vagus nerve stimulation is currently a treatment for epilepsy and for individuals who do not respond to medication or who are not candidates for surgery. The stimulator is surgically implanted like a pacemaker and connected to the vagus nerve. It is programmed to deliver stimulation during a specific time period.
The implant was developed by Cyberonics to suppress seizures in patients with epilepsy by delivering pulses of current to the vagus nerve.
"If this proves effective, this could possibly be a treatment for people who suffer from severe anxiety disorders," Markus said.
Jensen said the project, which started a year ago, will continue until the end of the summer when Markus receives her doctoral degree.
"Tiffanie is a very talented graduate student who is pursuing a research project that may contribute to significant advancements in anxiety and panic disorders," Jensen said.
Reporter Keva Gaston can be reached at kgaston@dailyegyptian.com
Published on 11/17/05; 12:24:44 PM
