The roles of modern and ancestral visual pathways in the mammalian brain, for defensive behaviours and spatial navigation

In order to survive, animals need to avoid predators and skillfully navigate the environment. These behaviors critically depend on the sense of vision. In mammals, two distinct systems process visual information: the evolutionarily ancient "superior colliculus" and the modern "visual cortex". We will define their relative functions in two natural behaviors essential for survival: (1)innate defensive responses and (2)spatial navigation. 1)We will study the visual cortex's role in controlling innate defensive behaviors triggered by the superior colliculus. We will focus on the mouse postrhinal-cortex (POR), capitalizing on my discovery that the superior colliculus has, through POR, a dedicated cortical space from which it receives direct excitatory feedback.(Beltramo,Science,2020). We will test the hypothesis that POR, relaying contextual information about the estimated threatening nature of visual stimuli, controls collicular function's plasticity. By silencing distinct cortico-collicular projections, we will determine how the visual cortex shapes the flexibility of colliculus-mediated innate behaviors. 2)We will investigate the contributions of the two visual pathways in spatial navigation, studying how visual input is transformed into the spatial maps found in the entorhinal/hippocampal formation. Perturbing the activity of distinct visual streams, we will establish how the superior colliculus and visual cortex influence the internal maps that guide navigation.