This lecture delves into the development of a mathematical model of the brain, exploring the brain's organization from molecular to behavioral levels. The instructor discusses the hierarchical network of brain regions, emphasizing the visual cortex as a model. The lecture covers the global organization of the cerebral cortex, the functional subdivisions of the visual cortex, and the dynamics of local populations in the brain. Mathematical equations describing neuronal dynamics and the emergence of gamma-band rhythms are explained. The lecture concludes with insights into the dynamics across the cortical surface, illustrated with a model of the macaque visual cortex. Throughout, the focus is on understanding the brain's complex structure and dynamics through mathematical modeling.