<p>(a) Discretized sequence of the neural response and stimulus. Each stimulus consists of a combination of biphasic pulses applied to all 20 electrodes. Stimuli that evoked a spike in the neuron are recorded in the stimulus matrix <b>S</b><sub>D.</sub> (b) STC was conducted on the stimuli generating a response, <b>S</b><sub>D</sub>, to separate the stimulus space into a positive and negative region (+ and ×). The x-axis corresponds to the first eigenvector (); the y-axis corresponds to the second eigenvector (). Not all stimuli generated a response in the neuron. Shown in black are the total applied stimuli, <b>S</b><sub>T</sub>, which are overlaid by stimuli <b>S</b><sub>D</sub> (white crosses). Also shown are the projections of the electrical receptive fields, (large diamond) and (large circle).</p
