The task structure is illustrated in Fig. 1 A and B. On one wall of the recording chamber, a central port was located above two adjacent fluid wells. Directional lights were located next to the fluid wells. Each trial began with the illumination of house lights that instructed the rat to nose-poke into the central port. After 1 s, a directional light to the rats left or right was flashed for 100 ms. On 80% of trials (GO trials) presentation of this directional cue light instructed the rat to exit the port and respond in the direction of the light in order to receive reward. On the remaining 20% of trials, the initial sequence of events was identical; however, a second directional cue light was illuminated in the opposite direction 0 to 100 ms after the rat exited the port. During these trials, rats had to respond in the direction of the second light in order to receive the reward.
