title: Evolution of optogenetic microdevices.
abstract: Implementation of optogenetic techniques is a recent addition to the neuroscientists' preclinical research arsenal, helping to expose the intricate connectivity of the brain and allowing for on-demand direct modulation of specific neural pathways. Developing an optogenetic system requires thorough investigation of the optogenetic technique and of previously fabricated devices, which this review accommodates. Many experiments utilize bench-top systems that are bulky, expensive, and necessitate tethering to the animal. However, these bench-top systems can make use of power-demanding technologies, such as concurrent electrical recording. Newer portable microdevices and implantable systems carried by freely moving animals are being fabricated that take advantage of wireless energy harvesting to power a system and allow for natural movements that are vital for behavioral testing and analysis. An investigation of the evolution of tethered, portable, and implantable optogenetic microdevices is presented, and an analysis of benefits and detriments of each system, including optical power output, device dimensions, electrode width, and weight is given. Opsins, light sources, and optical fiber coupling are also discussed to optimize device parameters and maximize efficiency from the light source to the fiber, respectively. These attributes are important considerations when designing and developing improved optogenetic microdevices.
authors.affiliation: Deakin University School of Engineering , Faculty of Science, Engineering, and Built Environment, 75 Pigdons Road, Waurn Ponds, Victoria 3216, Australia ; Mayo Clinic Department of Psychiatry and Psychology , 200 First Street SW, Rochester, Minnesota 55905, United States.
authors.forename: Rajas P
authors.initials: RP
authors.lastname: Kale
authors.affiliation: Deakin University School of Engineering , Faculty of Science, Engineering, and Built Environment, 75 Pigdons Road, Waurn Ponds, Victoria 3216, Australia.
authors.forename: Abbas Z
authors.initials: AZ
authors.lastname: Kouzani
authors.affiliation: Deakin University School of Medicine , 75 Pigdons Road, Waurn Ponds, Victoria 3216, Australia.
authors.forename: Ken
authors.initials: K
authors.lastname: Walder
authors.affiliation: Deakin University , IMPACT Strategic Research Centre, Faulty of Health, School of Medicine, Barwon Health, Geelong, Victoria, Australia ; Orygen , National Centre of Excellence in Youth Mental Health, Department of Psychiatry, 35 Poplar Road, Parkville, Victoria 3052, Australia ; University of Melbourne , Florey Institute of Neuroscience and Mental Health, 30 Royal Parade, Parkville Victoria 3052, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Berk
authors.affiliation: Mayo Clinic Department of Psychiatry and Psychology , 200 First Street SW, Rochester, Minnesota 55905, United States.
authors.forename: Susannah J
authors.initials: SJ
authors.lastname: Tye
keywords: behavioral tests; fiber coupling; neurology; optogenetics; portable microdevices; psychiatry; tethering