Deep Brain Stimulation (DBS) has demonstrated outstanding results for the treatment of medically intractable Parkinson’s disease (PD), essential tremor and other neurological and psychiatric disorders, such as Obsessive Compulsive Disorder (OCD) and major depression [1,2]. Despite widespread proliferation, efficacy of DBS treatment is limited primarily because of two key limitations as shown in Fig. 1: (a) non-specific activation of regions implicated in DBS side effects, and (b) inefficient neurostimulation due to complex anatomical structure and axonal orientations of target regions. Thus, there is a need to develop approaches to DBS that achieve more precise target selection and efficient activation of axonal pathways within the brain.
Recent efforts in target selection has focused on shaping the stimulation field by using multichannel electrodes for current steering . These multichannel electrodes are limited to cylindrical lead configuration and can only correct for small spatial localization errors, and they do not utilize the direction of the electrical field’s gradients to stimulate neurons depending on their orientation (mainly orientation of axons). Thus, there is a critical need for new electrode architectures that enable both spatial steering and stimulation field orientation tuning capabilities. Here we present the Flex-DBS, a novel DBS electrode lead architecture that harnesses recent advances in flexible probe fabrication and precision guidance strategy to mechanically reconfigure electrodes in three dimensional orientations within anatomically complex brain tissue. Further, it incorporates dense arrays of electrodes with each lead that allow stimulation field orientation tuning.