Online 3D simulation of extracellular recordings with morphologically reconstructed neurons

Extracellular recordings are a key tool to study the activity of neurons in vivo. Especially in the case of experiments with behaving animals, however, the tedious procedure of electrode placement can take a considerable amount of expensive and restricted experimental time. Furthermore, due to tissue drifts and other sources of variability in the recording setup, the position of the electrodes with respect to the neurons under study can change, causing low recording quality. Here, we developed a system online simulation of extracellular recordings that allows for feedback from electrode positioning systems. The simulator is based on realistically reconstructed 3D neurons. The shape of the extracellular waveform is estimated from their morphology for every point on a 3D grid around the neurons. If a recording device is close to a neuron, the corresponding waveform for its spikes is calculated from that grid by interpolating the waveforms of the adjacent grid positions. This way we can simulate a realistic recording environment in which an unconstrained movement of electrodes and neurons and an interaction with a positioning system and online spike sorter is possible