title: A multi-site array for combined local electrochemistry and electrophysiology in the non-human primate brain.
abstract: BACKGROUND
  Currently, the primary technique employed in circuit-level study of the brain is electrophysiology, recording local field or action potentials (LFPs or APs). However most communication between neurons is chemical and the relationship between electrical activity within neurons and chemical signaling between them is not well understood in vivo, particularly for molecules that signal at least in part by non-synaptic transmission.
  
  
  METHODS
  We describe a multi-contact array and accompanying head stage circuit that together enable concurrent electrophysiological and electrochemical recording. The array is small (<200 μm) and can be assembled into a device of arbitrary length. It is therefore well-suited for use in all major in vivo model systems in neuroscience, including non-human primates where the large brain and need for daily insertion and removal of recording devices places particularly strict demands on design.
  
  
  RESULTS
  We present a protocol for array fabrication. We then show that a device built in the manner described can record LFPs and perform enzyme-based amperometric detection of choline in the awake macaque monkey. Comparison with existing methods Existing methods allow single mode (electrophysiology or electrochemistry) recording. This system is designed for concurrent, dual-mode recording. It is also the only system designed explicitly to meet the challenges of recording in non-human primates.
  
  
  CONCLUSIONS
  Our system offers the possibility for conducting in vivo studies in a range of species that examine the relationship between the electrical activity of neurons and their chemical environment, with exquisite spatial and temporal precision.
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA. Electronic address: anita.disney@vanderbilt.edu.
authors.forename: Anita A
authors.initials: AA
authors.lastname: Disney
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: Collin
authors.initials: C
authors.lastname: McKinney
authors.affiliation: California Institute for Telecommunications and Information Technology (CalIT2), University of California San Diego, La Jolla, CA, USA.
authors.forename: Larry
authors.initials: L
authors.lastname: Grissom
authors.affiliation: California Institute for Telecommunications and Information Technology (CalIT2), University of California San Diego, La Jolla, CA, USA.
authors.forename: Xuekun
authors.initials: X
authors.lastname: Lu
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA, USA.
authors.forename: John H
authors.initials: JH
authors.lastname: Reynolds
mesh_terms: D000818:Animals; D001143:Arousal / Q000502:physiology; D002138:Calibration; D002794:Choline / Q000378:metabolism; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004594:Electrophysiology / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D008253:Macaca mulatta / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology
chemical_list: D002794:Choline
keywords: Amperometry; Cortex; Neuromodulation; Primate; Visual system