Cell - 8 September 2016

Figure S3. Optical Stimulation Biased Choices in the Absence of Exogenous Reward, Related toFigure 6
The choice experiment illustrated inFigure 6A was repeated in monkey B in the absence of exogenous reward. That is, neither cue predicted delivery of reward (as
opposed to both cues predicting reward in the previous test). One cue predicted optical stimulation, the other did not.
(A) Blue line shows an example behavioral session with optical stimulation. The monkey started choosing randomly, then slowly but completely becamebiased to
the cue that predicted optical stimulation. The red line shows an example control behavioral session with electrical stimulation (600mA) in the same location. The
monkey quickly developed a preference for the option paired with electrical stimulation. Both lines were smoothed with a 5 point moving average. Blueand red ‘x’
above and below indicate actual trial-by trial choices in the optical and electrical stimulation sessions, respectively.
(B) Optical stimulation test was repeated with 8 never before seen cue pairs. We compared the percentage of choices for the stimulated option in the first thirty
trials against the same percentage in the last 30 trials. * = p < 0.001, t test. Error bars are SEM. across cue pairs.