Figure 5: (a) Estimated current amplitude (μA) as a function of stimulation amplitude (V). Each data point is an average of estimated currents across five tetrode tip positions. The data was fit to a polynomial: y=0.53x2+0.48x−0.25 (_2=0.00001). (b) Recorded signal amplitude (μV) as a function of stimulation amplitude (V). Note that the signal amplitudes for each sensor also follow a quadratic trend, and has a negative y-intercept. This agrees with the estimated current results in (a), and implies that the phenomenon is not caused by our method but rather by a signal transformation occurring between the stimulator, medium, and sensors.