IN DEPTH aims at developing the first brain implantable device able to gather simultaneously electrophysiology and optical signals with depth resolution and reduced invasiveness. Neuroscientists and neurosurgeons are indeed still limited in accessing and addressing deep brain structures, while the field would instead greatly benefit of low-invasiveness probes monitoring bio-electronic and optical signals with spatial resolution, for both neuroscience and neurosurgery applications. IN DEPTH will answer to the stakeholders needs with a close-to-market fully-integrated device based on minimally invasive tapered optical fibers (TFs) for multipoint light collection and electrophysiology. The system aims at novel applications in both neuroscience research and neurosurgery, with particular reference to cerebral disfunctions including Parkinson’s disease, schizophrenia, or epilepsy, and to fluorescence-guided resection of brain tumors, giving neurosurgeons the possibility to check also the tumor depth and monitor electrical activity during surgery. These aims will be achieved by implementing innovative and high-throughput fabrication process developed for non-planar surfaces, aiming at full compatibility with bench-top equipment for electrophysiology, optophysiology and neurosurgery.