Cerebral Cortex

Hardware matters. The neural organ largely responsible for cognition is the cerebral cortex of mammals. Cortex is a thin two-dimensional layered structure arranged with on the order of a few hundred interconnected regions that seem to be specialized for particular operations. Regions often show topographic organization. Early vision displays an interestingly distorted topographic map of the retinal input, audition has a topographic map of frequency, and there is a distorted map of the body surface on the somatosensory areas. Information in cortex is not “processed” with an orderly flow from raw input data to a final conclusion but seems instead to send information both backward and forward so sensory input and learned information work together for a consensus analysis. Relative to body size, a bigger brain is a better brain. The most common cell types are variants of pyramidal cells with pronounced lateral interconnections.