GABAA receptor mediated inhibition contributes to corticostriatal frequency filtering

► We measured the frequency response of cortical inputs to striatal medium spiny neurons over the range of 2-100 Hz. ► The average fEPSP response exhibited a non-linear relationship to frequency with characteristics of a low pass filter. ► Antagonists to CB1, D2 or nACh receptors did not significantly change the filter characteristics. ► Blocking GABAA receptors reduced both the stop band slope and the cut off frequency of the low pass filter.