Fig. 6.

Varying individual pulse amplitude has a negligible effect on frequency discrimination performance. (A) Monkey B’s performance vs. base frequency in the variable-amplitude experiment for a group of 4 electrodes with weak amplitude bias. The frequency difference was always 90 Hz for the variable-amplitude experiment due to hardware constraints (Methods). Error bars in A and B show the SEM across electrodes. (B) Performance when stimulus pulse trains were both variable-amplitude were split or were both constant-amplitude, for the same 4 electrodes with weak amplitude bias. The Inset illustrates variable-amplitude and constant-amplitude pulse trains. Changing spatial distribution of the ICMS-induced activity on a pulse-by-pulse basis had little to no effect on the animal’s ability to discriminate frequency.