Fig. 3.

Optrode designs: (a) optrode design made from a $62.5\mu \mathrm{m}$ core multimode fiber and a metal recording electrode;⁷ (b) integrated device that combines a multielectrode array and a fine illumination site;⁸⁸ (c) multiarray silicon probes with integrated optical fibers for spatiotemporal brain control and recording;⁸⁹ and (d) simultaneous local field potential recordings from mice tissue not expressing opsins with light-exposed metal (upper trace) and glass microelectrodes (middle trace). Light stimulation is represented in blue. Note the photo-electric artifacts in the upper trace (modified from Ref. 74).