Neural representation of action symbols in primate frontal cortex

Subjects and surgical procedures Data were acquired from two adult male macaques ( Macaca mulatta , average weight of 17 kg (subject 1 (S1)) and 10 kg (S2), average age of 9 years (S1) and 7 years (S2)). This sample size was chosen to match the standard for neural recording studies of behaviour in monkeys 22 , 24 . All animal procedures complied with the NIH Guide for the Care and Use of Laboratory Animals and were approved by the Institutional Animal Care and Use Committee of the Rockefeller University (protocol 24066-H). After undergoing initial task training in their home cages, the subjects underwent two surgeries: the first to implant an acrylic head implant with a headpost and the second to implant electrode arrays. Both surgeries followed standard protocols, including for anaesthetic, aseptic and postoperative treatments. In the first surgery, a custom-designed MR-compatible Ultem headpost was implanted, surrounded by a bone cement cranial implant, or a headcap (Metabond, Parkell and Palacos, Heraeus), which was secured to the skull using MR-compatible ceramic screws (Rogue Research). After a 6-month interval, to allow bone to grow around the screws and for the subject to acclimate to performing the task during head fixation via the headpost, we performed a second surgery to implant 16 floating microelectrode arrays (32-channel FMA, Microprobes for Life Science) using standard procedures 69 . …