title: A coaxial optrode as multifunction write-read probe for optogenetic studies in non-human primates.
abstract: BACKGROUND
  Advances in optogenetics have led to first reports of expression of light-gated ion-channels in non-human primates (NHPs). However, a major obstacle preventing effective application of optogenetics in NHPs and translation to optogenetic therapeutics is the absence of compatible multifunction optoelectronic probes for (1) precision light delivery, (2) low-interference electrophysiology, (3) protein fluorescence detection, and (4) repeated insertion with minimal brain trauma.
  
  
  METHODS
  Here we describe a novel brain probe device, a "coaxial optrode", designed to minimize brain tissue damage while microfabricated to perform simultaneous electrophysiology, light delivery and fluorescence measurements in the NHP brain. The device consists of a tapered, gold-coated optical fiber inserted in a polyamide tube. A portion of the gold coating is exposed at the fiber tip to allow electrophysiological recordings in addition to light delivery/collection at the tip.
  
  
  RESULTS
  Coaxial optrode performance was demonstrated by experiments in rodents and NHPs, and characterized by computational models. The device mapped opsin expression in the brain and achieved precisely targeted optical stimulation and electrophysiology with minimal cortical damage.
  
  
  METHODS
  Overall, combined electrical, optical and mechanical features of the coaxial optrode allowed a performance for NHP studies which was not possible with previously existing devices.
  
  
  CONCLUSIONS
  Coaxial optrode is currently being used in two NHP laboratories as a major tool to study brain function by inducing light modulated neural activity and behavior. By virtue of its design, the coaxial optrode can be extended for use as a chronic implant and multisite neural stimulation/recording.
authors.affiliation: School of Engineering, Brown University, Providence, RI, USA. ilker_ozden@brown.edu
authors.forename: Ilker
authors.initials: I
authors.lastname: Ozden
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Yao
authors.initials: Y
authors.lastname: Lu
authors.forename: Travis
authors.initials: T
authors.lastname: May
authors.forename: Joonhee
authors.initials: J
authors.lastname: Lee
authors.forename: Werapong
authors.initials: W
authors.lastname: Goo
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: O'Shea
authors.forename: Paul
authors.initials: P
authors.lastname: Kalanithi
authors.forename: Ilka
authors.initials: I
authors.lastname: Diester
authors.forename: Mohamed
authors.initials: M
authors.lastname: Diagne
authors.forename: Karl
authors.initials: K
authors.lastname: Deisseroth
authors.forename: Krishna V
authors.initials: KV
authors.lastname: Shenoy
authors.forename: Arto V
authors.initials: AV
authors.lastname: Nurmikko
mesh_terms: D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003627:Data Interpretation, Statistical; D004566:Electrodes; D055724:Electrophysiological Phenomena / Q000502:physiology; D004852:Epoxy Compounds; D005453:Fluorescence; D008253:Macaca mulatta; D008670:Metals; D051379:Mice; D008822:Mice, Transgenic; D055616:Microtechnology; D009010:Monte Carlo Method; D055355:Opsins / Q000378:metabolism; D055100:Optical Fibers; D062308:Optogenetics / Q000295:instrumentation* / Q000379:methods*; D019047:Phantoms, Imaging; D011323:Primates / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D012815:Signal Processing, Computer-Assisted; D013696:Temperature
chemical_list: D004852:Epoxy Compounds; D008670:Metals; D055355:Opsins
keywords: Fluorescence detection; Light propagation in tissue; Non-human primates; Optoelectronic devices; Optogenetics; Tissue heating