This lecture explores the functional circuits of the brain related to sensory perception and external world representation. It covers topics such as the thalamus communication with the cortex, energy-saving mechanisms in the neocortex, self-generated sensory feedback significance, inhibitory control of instinctive behavior, minute-scale waves of activity in the entorhinal cortex, time perception in the brain, new models of human hearing via machine learning, and the role of the primary visual cortex. The presentation also delves into the divisions of the nervous system, including the forebrain, diencephalon, midbrain, and hindbrain, discussing structures like the thalamus, hypothalamus, and basal ganglia.