Selectivity and Spatial Distribution of Signals From the Receptive Field Surround in Macaque V1 Neurons

Abstract

Selectivity and spatial distribution of signals from the receptive field surround in macaque V1 neurons. J Neurophysiol 88: 2547-2556, 2002; 10.1152/jn.00693.2001. The responsiveness of neurons in V1 is modulated by stimuli placed outside their classical receptive fields. This nonclassical surround provides input from a larger portion of the visual scene than originally thought, permitting integration of information at early levels in the visual processing stream. Signals from the surround have been reported variously to be suppressive and facilitatory, selective and unselective. We tested the specificity of influences from the surround by studying the interactions between drifting sinusoidal gratings carefully confined to conservatively defined center and surround regions. We found that the surround influence was always suppressive when the surround grating was at the neuron's preferred orientation. Suppression tended to be stronger when the surround grating also moved in the neuron's preferred direction, rather than its opposite. When the orientation in the surround was 90°from the preferred orientation (orthogonal), suppression was weaker, and facilitation was sometimes evident. The tuning of surround signals therefore tended to match the tuning of the center, though the tuning of the surround was somewhat broader. The tuning of suppression also depended on the contrast of the center grating-when the center grating was reduced in contrast, orthogonal surround stimuli became relatively more suppressive. We also found evidence for the tuning of the surround being dependent to some degree on the stimulus used in the center-suppression was often stronger for a given center stimulus when the parameters of the surround grating matched the parameters of the center grating even when the center grating was not itself of the optimal direction or orientation. We also explored the spatial distribution of surround influence and found an orderly relationship between the orientation of grating patches presented to regions of the surround and the position of greatest suppression. When surround gratings were oriented parallel to the preferred orientation of the receptive field, suppression was strongest at the receptive field ends. When surround gratings were orthogonal, suppression was strongest on the flanks. We conclude that the surround has complex effects on responses from the classical receptive field. We suggest that the underlying mechanism of this complexity may involve interactions between relatively simple center and surround mechanisms.

Two Distinct Mechanisms of Suppression in Human Vision

“…Two forms of suppression have been isolated in the primary visual cortex of cats and monkeys. One is "surround suppression," in which the mask has the orientation preferred by the neuron but is presented outside the receptive field (DeAngelis et al, 1994;Cavanaugh et al, 2002). The other is "overlay suppression," in which the mask is presented within the receptive field (superimposed on the test) and can have any orientation (Morrone et al, 1982;Bonds, 1989;DeAngelis et al, 1992;Carandini et al, 1997).…”

TiViPE Simulation of a Cortical Crossing Cell Model

“…The difference is in the modulation by surrounding elements, hence it could tune neurons to a graded specialization for processing junctions [18,4]. Typically the surround influence was suppressive when the surround grating was at the neuron's preferred orientation [3], but when the orientation in the surround was perpendicular to the preferred orientation facilitation became evident. Neural responses to crossings were on average more than 3 times stronger [16], but they also respond to a grating or a single bar of a preferred orientation [18,16,3,7].…”

“…Recent reports [18,16,3,7] have demonstrated that the responsiveness of neurons in V1 is modulated by stimuli placed outside their CRFs. Cells with suppressive surround influence corresponding to surround orientation of a grating or bar pattern at the neuron's preferred orientation were found.…”

“…This non classical surround provides input from a larger portion of the visual scene than originally thought, permitting integration of information at early levels in the visual processing stream. Recent works indicate that neuronal surround modulation at cross-orientation, an orientation orthogonal to the preferred orientation of the CRF, play a key role in intermediate-level visual tasks, such as perceptual pop-out [14], contrast facilitation [3,20], and contextual modulation [8,4,5], and could endow neurons with a graded specialization for processing angular visual features such as corners and junctions [18,4].…”

Visual saliency: a biologically plausible contourlet-like frequency domain approach

“…In addition, data from (Cavanaugh et al 2002) suggest that the surround size depends on the receptive field size of V1 simple cells. In order to be consistent with these findings, we first decompose the image into many scales using the Laplacian pyramid.…”