Figure 8.

Forebrain activity during closed- and open-loop navigation in a dark-modulated environment is largely stimulus-locked. (A–C) Recordings from pallial neurons during two-dimensional darkness avoidance. For 5 min, fish navigated a virtual environment. Next, the stimulus presented during this period was repeated in open-loop. Neural activity during the first 5 min shown in blue; activity during the five minutes of stimulus replay shown in red. Neurons a–c are in the same fish, over the same period. (A) Activity in this neuron is identical during the closed- and open-loop periods, indicating that this is a visually-driven neuron with activity that is highly predictable from the visual stimulus alone. (B,C) Two neurons that are stimulus-driven, but whose activity is differently modulated during closed-loop and open-loop replay. Differences in activity may represent differences in the state of the brain during closed- and open-loop control. (D) For comparison, a neuron in the inferior olive with activity that is different during closed-loop and open-loop replay. Activity in this neuron correlates with motor output (bottom). Data were obtained using a one-dimensional OMR assay (Ahrens et al., 2012). Swim patterns during closed- and open-loop are qualitatively different, with behavior in closed-loop being more ongoing, and behavior in open-loop characterized by periods of quiescence and periods of vigorous swimming. These patterns are also reflected in the neural activity.