Axonal gap junctions in the fly visual system enable fast prediction for evasive flight maneuvers

The visual system must make predictions to compensate for inherent delays in its processing, yet little is known, mechanistically, about how prediction aids natural behaviors. Here we show that despite a 30ms intrinsic processing delay, the vertical motion sensitive (VS) network of the blowfly can achieve maximally efficient prediction. This prediction enables fine discrimination of input motion direction during evasive flight maneuvers, which last just 40ms. Combining a rich database of behavioral recordings with detailed compartmental modeling of the VS network, we further show how the VS network implements this optimal prediction. The axonal gap junctions between the VS cells are crucial for optimal prediction during the short timespan of evasive maneuvers. Its subpopulation output further selectively conveys predictive information about the future visual input to the downstream neck motor center. Our work predicts novel sensory-motor pathways that link prediction to behavior.