Stimulus-resistant neural recording amplifier

The capability to use the same microelectrode for electrical stimulation of neurons, as well as for neural signal recording from neurons in the vicinity of the electrode, has historically been a goal of neuroscientists. During, and after, stimulation the stimulus artifact effectively disables the recording system until the residual effects of the artifact have dissipated. The only practical way to successfully record neural signals in the presence of stimulus pulses is to fully integrate the constant-current bi-directional stimulation circuitry with a specialized bioelectric recording amplifier on the same electronic chip. This is because post-stimulus electrode polarization recovery, amplifier blanking, and low-noise amplifier circuitry must be intimately tied to the stimulus circuitry, and such functional integration can only be obtained by implementing the combined circuitry as one application specific integrated circuit (ASIC) design. Toward this goal, a topology for a neural recording amplifier with rapid recovery characteristics was designed and tested using discrete components, and was successfully used to suppress stimulation artifacts generated by a nearby electrode in vitro.