Neurophysiology in Awake Behaving Monkeys

Performance of the EPC was tested in awake behaving monkeys. Following initial training monkeys were implanted with a head holder, eye coil, and recording chambers above V1 under general anesthesia and sterile conditions. For the anesthesia animals were initially sedated with a 0.1 ml/kg ketamine intra-muscular injection (100 mg/ml). Thereafter, bolus injections of propofol were administered intra-venously to allow for tracheal intubation (0.05–0.1 ml). Prior to surgery a bolus injection of dexamethosone sodium phosphate was administered i.v. (0.33 mg/kg). During surgery anesthesia was maintained by gaseous anaesthetic (1–3% sevoflurane) combined with continuous i.v. application of an opioid analgesic (Alfentanil, 156 μg/kg/h). The animal's rectal temperature, heart rate, blood oxygenation and expired CO₂ were continuously monitored during surgery. Immediately after surgery (and during the following 3–5 days) the animals were given antibiotics (Cephorex 0.5 ml/kg or Synolux 0.25 ml/kg) and analgesics (Metacam 0.1 ml/kg).
Following surgery the recording chambers were regularly cleaned under sterile conditions and 5-fluoro-uracil treatment was performed three times per week (Spinks et al., 2003 (link)). Despite 5-fluoro-uracil treatment it was necessary to perform dura scrapes every 6–8 weeks for the removal of fibrous scar tissue above the craniotomy.
All animal and surgical procedures were in accordance with the European Communities Council Directive 1986 (86/609/EEC), the National Institutes of Health guidelines for care and use of animals for experimental procedures, the Society for Neurosciences Policies on the Use of Animals and Humans in Neuroscience Research, and the UK Animals Scientific Procedures Act.