Fig. 5.
Timing of stimulation-driven effects on discriminability and comparison with the effect of a simulated phosphene. (A) A subset of neurons was tested with 20-ms trains of microstimulation (four current pulses at 200 Hz). The average difference in response discriminability (ΔAROC, stimulation minus control) of preferred (p) and blank (background) stimuli in the RF (dotted circle) is shown around the time of FEF microstimulation. Shading indicates SEM. The decrease in discriminability seen during microstimulation is caused by the stimulation artifact. (B) The effect of a simulated phosphene (Gaussian brightness patch superimposed on a RF stimulus; Upper) on response discriminability of preferred and blank stimuli was examined in a population of V4 neurons (n = 11). The difference in ROC area (phosphene minus control) is shown around the time of the simulated phosphene presentation. Shading indicates SEM.