Converting neural signals from place codes to rate codes

The nervous system uses two basic types of formats for encoding information . The parameters of many sensory (and some premotor) signals are represente d by the pattern of activity among an array of neurons each of which is opt imally responsive to a different parameter value, This type of code is comm only referred to as a place code. Motor commands, in contrast, use rate cod ing: the desired force of a muscle is specified as a monotonic function of the aggregate rate of discharge across all of its motor neurons. Generating movements based on sensory information often requires converting signals f rom a place code to a rate code. In this paper I discuss three possible mod els for how the brain does this.