Fig 9. Orientation to a goal direction supported by the MB long-term visual memory.

A. Mushroom bodies model diagram. The visual Projection Neurons (vPN) correspond to the visual units (Fig 2) extracting edge from the panoramic view. Each KC has a random post-synaptic connection pattern with 2 to 5 vPNs and a pre-synaptic connection to the MB output neuron (MBON). During the learning procedure, the memory reward signal (DAN) is activated and induces the decrease of the synaptic strength between the activated KCs and the MBON. The MBON activity is then used as the reward signal to adapt the CX circuit. B. Schematic of the learning phase before the simulation. The agent faces the feeder during 100 steps from a position in between the feeder and the center of the arena (learning pose), with an orientation error from −15 to 15°. The MB model memory is updated during this phase (DAN active). C. Example paths from the retrieval experiments using the MB model as an input for the CX model. D. Final direction vectors for 50 simulations with the feeder at 0° and the cue oriented at 45°. The red arc shows the median (dot) 95% C.I. obtained by bootstrapping (rep = 10000). E. Averaged right (red) and left (green) EPG-PFL3 synapses weights (shaded area: ±s.d.) obtained from 50 simulations.