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If you look at a human or mammal’s brain from the top or the sides, what you see is the neocortex. In humans, this part of the brain, which is about 2-4 mm thick (a thickness somewhere between the size of the point of a crayon and the eraser end of a pencil), forms ridges or deep grooves called sulci. The neocortex in humans controls sensory perception, generation of motor commands, spatial reasoning, conscious thought, and language.

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