Receptive fields and suppressive fields in the early visual system

Initial models proposed that these operations are weighted sums, with weights given by a neuron’s receptive field. These models explain the basic features of response selectivity. They were later extended to explain a number of suppressive effects originating within and outside the region of the receptive field. The resulting models rely on division. In this division, the receptive field feeds into the numerator, and the denominator is provided by a larger, non-classical suppressive field. While the receptive field confers to a neuron the basic selectivity for stimulus properties, the suppressive field modulates responsiveness. A divisive suppressive field confers to neurons in early visual system a number of computational advantages. Recent evidence in higher cortical areas suggests that the modulation of divisive suppression is the primary means of operation of visual attention. In this chapter I summarize research in receptive fields and suppressive fields in lateral geniculate nucleus (LGN) and in primary visual cortex (V1). In the following, I refer to a “suppressive field” as though this term had wide acceptance. In reality, the concept has been proposed only for LGN neurons (Levick et al., 1972), and lies forgotten since 30 years. My hope is that it will find wide acceptance to describe responses of both LGN and V1 neurons. Receptive fields in LGN