Chapter 1 Population coding: a historical sketch

Abstract

Publisher Summary This chapter gives an overview of population coding. The chapter discusses a reliable sign or “signature” of a system that employs a distributed code where its neurons taken one at the time are broadly tuned along a dimension that, the system nonetheless appears to resolve with a high degree of precision. For visual cells, the dimension may be retinal location, wavelength, orientation, speed, direction, or at higher levels, form and position in head- or body-centered coordinates. Neurons in the auditory system respond to a wide range of sound frequencies and intensities, and the broad tuning of olfactory and gustatory neurons is well established. There is ample evidence that this characteristic applies to the primary motor cortex and superior colliculus. Progress has been made in estimating the distribution of activity in response to stimulation at some locus along the dimension involved. Neural systems are non-linear, the convolution techniques suitable for linear systems cannot be applied directly, and a major challenge is to develop methods to map the real distributions of activity to stimuli more complex than points.