Joana Neto has recently uploaded a new dataset of "paired recordings" in which the same neuron is simultaneously monitored by a pipette and silicon polytrode. She (along with many members of the Kampff Lab/CENIMAT/NeuroSeeker) has developed a new technique to easily target both probes to the same location in the brain (described in her recent paper). Her dataset provides the vital "ground truth" necessary to evaluate new methods for neural recording as well as new algorithms for isolating one neuron from the background cacophony (i.e. "spike sorting").
In addition, this data can also be used to investigate how one neuron's activity relates to the background field, how an action potential propagates through extracellular space, whether different spike waveforms correspond to different extracellular signatures, and countless other questions. These questions are for you to ask...just let us know if you find out anything cool.