Although Parkinson’s disease is often associated with motor symptoms such as stiffness, poor balance and trembling, the first symptoms are often sensory and include a reduced sense of touch and smell. In a study on mice, researchers have now been able to identify neural circuits and mechanisms behind this loss of sensory perception. The study, which was published in Neuron, may open avenues to methods of earlier diagnosis.

In this study, researchers used a light puff of air to stimulate either the right or left whiskers of mice, some of which had an especially low number of dopamine cells, while using a new optogenetic tool called an optopatcher. Applying this technique, which enables the activity of neurons to be recorded during manipulation with light, they were able to see which neurons in the basal ganglia were active and when they transmitted signals.

The researchers report that the neurons in mice with very low levels of dopamine did not properly signal in response to whisker stimulation and could not accurately tell the difference between right and left. However, after being treated with a common Parkinson’s drug called L-DOPA, this ability was regained.

The researchers say they hope that the discovery will open the way for methods of earlier diagnosis.

Paper: “Dopamine Depletion Impairs Bilateral Sensory Processing in the Striatum in a Pathway-Dependent Manner”

Reprinted from materials provided by the Karolinska Institutet.

август 7, 2017