Compact and soft probes for optical brain stimulation

The brain, director of the nervous system, has long captivated people with its outstanding functions and enigmatic nature. Nowadays, the precise mechanisms behind its operations are still an ongoing debate. Therefore, a deeper understanding of brain’s functions is also crucial to develop therapies for neurological disorders such as epilepsy, Alzheimer’s syndrome, dementia or depression. One of the technics employed for this is optogenetics (OG), a technique where specific classes of neurons can be excited or inhibited by illumination. The combination of optogenetics with fluorescence microscopy permits to see how few neurons communicate. In addition, this technique has shown potential in alleviating pathological behaviors of some neurons, which are the actual causes of the disorders. While optogenetics can provide a solid approach to study and stimulate neurons, its therapeutic implementation constitutes a technological challenge, the implantation of optical probes in the brain is required. Chronical implantations of optical probes must meet many requirements to limit the foreign body response of the tissues such as dimensions, flexibility and biocompatibility. Currently, the available probes have the required optical properties but are stiff (glass fibers) and relatively bulky (diameter of hundreds of µm). In this fashion, the actual probes are implantable only for short periods, constituting a limitation for further applications. The goal of this project is the development of probes that can overcome all the aforementioned limitations. To do so, soft and flexible materials that can also provide sufficient light transmission properties must be selected.  The development of this kind of probe will permit a deeper understanding of mechanisms underlying the neurological system and enable a potential translation of OG therapies from the laboratory to the clinics.