In these experiments we use (single channel) carbon fibers or multi-channel platinum electrode arrays to simultaneously monitor neuromodulator levels (constant potential amperometry) and neural activity (physiology) in the neocortex during behavior. This allows us to relate the activity of neurons (as spikes or local field potentials) to their chemical environment. Currently we are using these methods to look at the relationship between the release of noradrenaline and/or acetylcholine in the cortex and performance on various attention and learning tasks. We make our recording devices in-house, which gives us enormous flexibility in matching the recording tools to the demands of the experiment. Using the cleanroom facilities at the Vanderbilt Institute for Nanoscale Engineering, we build our existing tools and develop new devices that allow for expanded recording capabilities.