Despite a rapid accumulation of observations about patho-physiological mechanisms, it is still mostly serendipity and empiric adjustments that dictate clinical practice while more efficient logically designed interventions remain rather exceptional. Some technical issues still limit the long term use in humans but realistic perspectives quickly emerge.

New paths could be opened toward a rich panel of clinical applications. This brings about the possibility to transfer this technology into the clinic as a possible alternative to DBS and neuromodulation.

Recent advancements of viral vector technology for gene transfer substantially reduce vector-associated cytotoxicity and immune responses. Optogenetics has experienced tremendous progress since its first in vivo applications about 10 years ago. Optogenetics, in contrast, offers the perspective of much more selective actions on the various physiological structures, provided that the stimulated cells are rendered sensitive to the action of light. On the other hand, the current practice of DBS is hampered by the relatively coarse level of neuromodulation achieved. The focal action of electrical stimulation can yield better responses and it exposes the patient to fewer side effects compared to pharmaceuticals distributed throughout the body toward the brain.

4Environment, Health and Safety, Imec, Leuven, Belgiumĭeep Brain Stimulation (DBS) has evolved into a well-accepted add-on treatment for patients with severe Parkinsons disease as well as for other chronic neurological conditions.

3Life Science and Imaging, Imec, Leuven, Belgium.

2Neuroscience Research Flanders, Leuven, Belgium.1LCEN3, Department of Neurology, Institute of Neuroscience, Ghent University, Ghent, Belgium.Jean Delbeke 1, Luis Hoffman 2, Katrien Mols 2,3, Dries Braeken 3 and Dimiter Prodanov 2,4 *

And then there was light equation