Optical characterization of an infrared neural optrode

The optrode device characterized in this paper provides a minimally invasive way of multimodal sensing and modulating the behavior of the brain tissue. Besides the capabilities of delivering the infrared (IR) light and multichannel electrophysiological recording of neural activity, a resistance thermometer is also integrated on the electrode's shaft. The peculiarity of our design is that the electrode shaft act like a mechanical carrier of the micro components and an IR waveguide in parallel. These three modalities make the microdevice able to record the evoked neural response and the background temperature in the close vicinity of the tissue illuminated by IR light. The IR neural stimulation method (INS) has been used several times to stimulate the superficial layer of the intact brain however, delivering the IR light into the deep neural tissue has larger potential in view of therapeutic use. In this paper the optical characterization of fully assembled optrode devices is presented prior to in vivo validation.