Pseudo-synchronous system for recording action and field potentials simultaneously

Large-scale simultaneous recording could help us to understand the complex behavior of neuronal ensembles. Field potentials (FPs) and multi-unit activities (MUAs) are to complement each other. Here, a hybrid multichannel system was proposed to record FPs and MUAs. Firstly, a three-stage signal-conditioning unit was designed that offered low noise, low cost and excellent line-driving capabilities. The parallel architecture of the filter stage, just before the analog-to-digital (A/D) converter card, allowed the MUA and FPs to be recorded simultaneously without further signal processing. Secondly, to obtain a precision map, a 64-channel high-speed A/D card and its software program were purchased, which allowed “pseudo-synchronous” acquisition among different channels. Finally, a practical application of this system in investigating cortical responses showed that it met the requirements of ensemble recording. The detailed design considerations and methods for implementing the system could be valuable to other neuroscience laboratories.