A small area of the brain called the anterior cingulate cortex (ACC) in the thalamus can be optically stimulated to control pain, University of Texas at Arlington scientists have found.

The researchers used optogenetic stimulation with a blue laser to control pain sensation in a mouse, created by a chemical irritant (formalin) and mechanical pain, such as that experienced following a pinprick or pinch.

“Our results clearly demonstrate, for the first time, that optogenetic stimulation of inhibitory neurons in ACC leads to decreased neuronal activity and a dramatic reduction of pain behavior,”said Samarendra Mohanty, an assistant professor of physics who leads the Biophysics and Physiology Lab in the UT Arlington College of Science and co-author on an open-access paper published online Wednesday Feb. 25 by the journal PLOS ONE.

Other researchers have previously experimented with using electrodes to stimulate inhibitory neurons (to reduce pain) in the ACC, but such stimulation lacks specificity and leads to activation of both excitatory and inhibitory neurons, he said.

Mohanty suggested that the results could lead to increased understanding of pain pathways and strategies for managing chronic pain, which often leads to severe impairment of normal psychological and physical functions.

However, “while reducing the sensation for chronic pain by optical stimulation, we still want to sense certain types of pain because they tell us to move our hands or legs away from something that is too hot or that might otherwise hurt us if we get too close,” Mohanty noted.

The team now plans to carry out localized non-invasive stimulation of small brain regions such as the ACC to better understand and control pain.

UT Dallas and University of Kentucky researchers also participated in the study. Mohanty’s lab is currently supported by a $384,269 two-year grant from the National Institutes of Health National Institute of Neurological Disorders and Strokes.

http://www.kurzweilai.net/controlling-pain-by-optogenetic-stimulation-of-the-brains-pain-center