Perceived contrast following adaptation to gratings of different orientations

Abstract

Using a contrast matching procedure, we measured the perceived contrast of vertical test gratings after adapting to other gratings of either vertical or horizontal orientation. The results show that both parallel and orthogonal adapting gratings reduce perceived contrast and do so proportionally more at low test contrasts than at high. The results are consistent with a single mechanism model proposed by Ross and Speed [(1991). Proceedings of the Royal Society (Series B), 246, 61-69] that assumes that adaptation to gratings repositions contrast-response transducer functions. They are not consistent with the notion of two different forms of adaptation, subtractive for parallel and multiplicative for orthogonal adaptors as proposed by Snowden and Hammett [(1992). Nature, 355, 248-250]. Nowhere is the reduction in perceived contrast by an orthogonal grating greater than that by a parallel grating of the same contrast. A direct comparison using two orthogonal adaptors confirms the greater potency of parallel adaptors, but also reveals interactions between the adaptors.

Shading and texture: separate information channels with a common adaptation mechanism?

“…They found that contrast threshold elevation was orientation-selective (Snowden, 1991), while the suprathreshold, contrast-reduction aftereffect was not clearly orientation-specific and (when the adapt and test gratings were orthogonal) it behaved like a multiplicative contrast gain control. Ross & Speed (1996) confirmed that the orientation selectivity of contrast adaptation disappears at high contrasts. They found that at low test contrasts, adapting to the same orientation ('parallel') gave a greater loss of perceived contrast than adapting to the orthogonal orientation, while at high test and high adapt contrasts the loss of perceived contrast was the same for parallel and orthogonal adapters, implying little or no orientation selectivity for contrast adaptation at high contrasts.…”

Four Days of Visual Contrast Deprivation Reveals Limits of Neuronal Adaptation

“…The fast process evident in our paradigm likely depends on the same rapid neural mechanisms of contrast adaptation that have been investigated in dozens of short-term laboratory studies [1][2][3][4][5][6][7][8][9][10][11][12][13]. The neural bases of these fast processes include gain and tuning changes in neurons in primary visual cortex (e.g., [7][8][9][10][11][12][13]).…”

“…In a contrast appearance judgment [5,14,21,22], observers adjusted the contrast of a horizontal pattern to match the apparent contrast of a weak vertical one (of 5% contrast, Figure 1B), and we measured the amount of adjustment required. Following deprivation, this value increased, indicating that the neural response to vertical contrast strengthened.…”

“…Such adaptation produces large perceptual effects, and its pervasiveness makes it a key part of understanding cortical function generally [1][2][3]. In visual contrast adaptation, for example, brief exposure to vertical stripes can dramatically alter the apparent orientation and intensity of similarly oriented patterns (e.g., [4][5][6][7]). However, many environmental changes are long lasting.…”

Selective Adaptation to Color Contrast in Human Primary Visual Cortex

“…Together, these results suggest that the fMRI signal in V1 is coupled to some of the neural events that underlie contrast appearance. Suprathreshold perceived contrast is a complicated computation, however, that can be influenced by a wide variety of factors, including some that have only minimal effects on detection thresholds (Ross and Speed, 1996;Snowden and Hammett, 1996). Important components of this computation may arise beyond striate cortex.…”