1. A method of stimulating a neurological target with at least one microelectrode, comprising: receiving a broadband signal; measuring through at least one microelectrode, respective electrical impedance values indicative of the microelectrode-tissue interface impedance at each of a plurality of different stimulation frequencies for each of the at least one microelectrodes; identifying from the electrical impedance values measured at each of the at least one microelectrodes a preferred stimulation frequency from the plurality of different stimulation frequencies; selecting a spectral sub-portion of the broadband signal, the spectral sub-portion including the preferred stimulation frequency; and stimulating the neurological target at the preferred stimulation frequency using the selected spectral sub-portion of the broadband signal.