We then compared the influence of activity in areas 8 and 46 of dlPFC and in area LIP of PPC on behavioral choice and behavioral

reaction time. Our results revealed that neuronal activity in each area influenced reaction time and behavioral choice to a different extent, in different task epochs. Two male rhesus monkeys (Macaca mulatta) weighing 5–8 kg were used in this study. All surgical and animal-use procedures in this study followed guidelines of the US Public Health Service Policy on Humane Care and Use of Laboratory Animals and the National Research Council’s Guide for the Care and Use of Laboratory Animals, and were reviewed and approved by the Wake Forest University Institutional

Dabrafenib chemical structure Animal Care and Use Committee. Two 20-mm diameter Protein Tyrosine Kinase inhibitor recording cylinders were implanted over dlPFC and PPC of the same hemisphere in each monkey (Fig. 1A). Extracellular activity of single units was recorded using arrays of 2–8 microelectrodes in each cylinder, either with glass-coated tungsten electrodes (250 μm diameter, impedance 1 MΩ at 1 kHz; Alpha-Omega Engineering, Nazareth, Israel) or epoxylite-coated tungsten electrodes (125 μm diameter, impedance 4 MΩ at 1 KHz; FHC, Bowdoin, ME, USA). Electrodes were advanced individually into the cortex with a microdrive system (EPS drive; Alpha-Omega Engineering). The electrical signal from each electrode was amplified, band-pass filtered between 500 Hz and 8 kHz, and recorded with a modular data acquisition system at 25 μs resolution (APM system; FHC). The anatomical location of electrode penetration was confirmed with MR imaging

of the brain obtained after implantation of the recording cylinders. In the prefrontal cortex, neuronal data were collected from areas 46 and 8a of the dlPFC including both banks of the principal sulcus and the surface cortex dorsal to the principal sulcus and posterior to but excluding the arcuate sulcus. In the PPC, recordings were obtained from the lateral bank of Histidine ammonia-lyase the intraparietal sulcus at depths > 3 mm from the surface of the cortex excluding area 7a, which is located superficially. The monkeys faced a computer monitor 60 cm away in a dark room with their head fixed. Eye position was sampled at 240 Hz, digitized, and recorded with an infrared eye position tracking system (model RK-716; ISCAN, Burlington, MA, USA). The visual stimulus presentation and behavior monitoring were controlled by in-house software (Meyer & Constantinidis, 2005) using the Psychophysics Toolbox (Brainard, 1997). The system was implemented in the MATLAB computational environment (Mathworks, Natick, MA, USA). Two different tasks were used in the present study: the delayed match-to-sample task (Fig. 1B) and the reaction-time task (Fig. 1C).