A Multimodal Deep Brain Stimulation Probe for Advanced Neuromodulation: Case Study for Depression

The current understanding of therapeutic effects of deep brain stimulation (DBS) in treatment-resistant depression (TRD) is constrained by the limitations of conventional DBS hardware. An advancement in hardware should enable DBS technology to supply additional information on the neurobiology of DBS intervention in addition to offering better and more precise stimulation. This dissertation, on one hand, is geared towards further exploring the neuromodulating effects of DBS in depression, and on the other hand, is focused on enabling a technological advancement of DBS hardware. In an animal model of depression (Flinders Sensitive Line, FSL), stimulation-evoked dopamine response was assessed and compared to a healthy Sprague Dawley (SD) group. The resulting release profile suggested differences across the depression and control groups, where the response amplitude was significantly higher and longer-lasting in the FSL group compared to the healthy control. To fabricate integrated multimodal devices, polyimide (PI) thin-film devices with glassy carbon (GC) and silicone-rubber based arrays with infrared laser-induced carbon interface were evaluated by means of their electrochemical characteristics and their compliance with the design of a DBS probe. In a subsequent step, a hybrid multimodal DBS probe comprising of a flexible PI thin-film device featuring 16 glassy carbon microelectrodes was designed and manufactured. The performed characterizations revealed sensitivity towards dopamine and showed no adverse effects under the applied electrochemical stress. Additionally, contrary to conventional DBS probes, the presented DBS technology showed no imaging artifacts in magnetic resonance imaging.