Vision is not olfaction: impact on the insect Mushroom Bodies connectivity

The Mushroom Bodies, a prominent and evolutionary conserved structure of the insect brain, are known to be the support of olfactory memory. There is now evidence that this structure is also required for visual learning, but the hypotheses about how the view memories are encoded are still largely based on what is known of the encoding of olfactory information. The different processing steps happening along the several relays before the Mushroom Bodies is still unclear, and how the visual memories actually may allow navigation is entirely unknown. Existing models of visual learning in the Mushroom Bodies quickly fall short when used in a navigational context. We discuss how the visual world differs from the olfactory world and what processing steps are likely needed in order to form memories useful for navigation, and demonstrate it using a computational model of the Mushroom Bodies embedded in an agent moving in through a virtual 3D world.