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

Our brain is the result of a long evolution. Over time, new brain regions superseded functions originally performed by preexisting areas. Newer structures did not replace older ones but rather integrated with them, increasing circuit complexity. What roles ancient and modern, functionally similar brain regions play in behavior? The visual system offers an ideal model for studying this question. Mammals have two coexisting brain structures processing visual information: the ancient "superior colliculus" and the phylogenetically newer "visual cortex". We will determine their relative roles in two natural behaviors crucial for survival: (1) innate defensive responses and (2) spatial navigation. Visually-evoked innate defensive behaviors, such as freezing upon detection of distant predators, critically increases survival chances. Equally important is the ability to navigate adroitly, creating internal ?spatial maps? of the environment. This project will provide crucial insight into how evolutionarily ancient and modern visual pathways interact to generate complex behaviors essential for survival.