title: A non-invasive head-holding device for chronic neural recordings in awake behaving monkeys.
abstract: BACKGROUND
  We have developed a novel head-holding device for behaving non-human primates that affords stability suitable for reliable chronic electrophysiological recording experiments. The device is completely non-invasive, and thus avoids the risk of infection and other complications that can occur with the use of conventional, surgically implanted head-fixation devices.
  
  
  METHODS
  The device consists of a novel non-invasive head mold and bar clamp holder, and is customized to the shape of each monkey's head. The head-holding device that we introduce, combined with our recording system and reflection-based eye-tracking system, allows for chronic behavioral experiments and single-electrode or multi-electrode recording, as well as manipulation of brain activity.
  
  
  RESULTS
  With electrodes implanted chronically in multiple brain regions, we could record neural activity from cortical and subcortical structures with stability equal to that recorded with conventional head-post fixation. Consistent with the non-invasive nature of the device, we could record neural signals for more than two years with a single implant. Importantly, the monkeys were able to hold stable eye fixation positions while held by this device, demonstrating the possibility of analyzing eye movement data with only the gentle restraint imposed by the non-invasive head-holding device.
  
  
  CONCLUSIONS
  We show that the head-holding device introduced here can be extended to the head holding of smaller animals, and note that it could readily be adapted for magnetic resonance brain imaging over extended periods of time.
authors.affiliation: McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
authors.forename: Satoko
authors.initials: S
authors.lastname: Amemori
authors.affiliation: McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Amemori
authors.affiliation: McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
authors.forename: Margaret L
authors.initials: ML
authors.lastname: Cantor
authors.affiliation: McGovern Institute for Brain Research and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States. Electronic address: graybiel@mit.edu.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Graybiel
mesh_terms: D000200:Action Potentials; D000818:Animals; D001921:Brain / Q000502:physiology; D003657:Decision Making / Q000502:physiology; D004567:Electrodes, Implanted; D004594:Electrophysiology / Q000295:instrumentation; D004867:Equipment Design; D053483:Eye Movement Measurements / Q000295:instrumentation; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006257:Head; D008253:Macaca mulatta; D009483:Neuropsychological Tests; D012149:Restraint, Physical / Q000295:instrumentation*; D012453:Saimiri; D014851:Wakefulness / Q000502:physiology
keywords: Chronic recording; Electrophysiology; Eye-tracking; Head holding; Primate