Coding of image contrast in central visual pathways of the macaque monkey

Sclar, Gary; Maunsell, John H. R.; Lennie, Peter

doi:10.1016/0042-6989(90)90123-3

Cited by 603 publications

(529 citation statements)

References 36 publications

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“…In these cases, the functions became compressive at the highest mask contrast tested. Webb et al, 2005;Naito et al, 2007), where the contrast response exponents are smaller and saturation is less evident (Derrington & Lennie, 1984;Sclar et al, 1990). For instance, an excitatory exponent of p 5 1 is consistent with Bonin et al's (2005) singlecell model of suppression in the LGN.…”

Section: The Excitatory and Suppressive Exponents (P And Q)supporting

confidence: 81%

A common contrast pooling rule for suppression within and between the eyes

2008

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Recent work has revealed multiple pathways for cross-orientation suppression in cat and human vision. In particular, ipsiocular and interocular pathways appear to assert their influence before binocular summation in human but have different (1) spatial tuning, (2) temporal dependencies, and (3) adaptation after-effects. Here we use mask components that fall outside the excitatory passband of the detecting mechanism to investigate the rules for pooling multiple mask components within these pathways. We measured psychophysical contrast masking functions for vertical 1 cycle/ deg sine-wave gratings in the presence of left or right oblique (645 deg) 3 cycles/deg mask gratings with contrast C%, or a plaid made from their sum, where each component (i) had contrast 0.5C i %. Masks and targets were presented to two eyes (binocular), one eye (monoptic), or different eyes (dichoptic). Binocular-masking functions superimposed when plotted against C, but in the monoptic and dichoptic conditions, the grating produced slightly more suppression than the plaid when C i $ 16%. We tested contrast gain control models involving two types of contrast combination on the denominator: (1) spatial pooling of the mask after a local nonlinearity (to calculate either root mean square contrast or energy) and (2) ''linear suppression' ' (Holmes & Meese, 2004, Journal of Vision 4, 1080-1089), involving the linear sum of the mask component contrasts. Monoptic and dichoptic masking were typically better fit by the spatial pooling models, but binocular masking was not: it demanded strict linear summation of the Michelson contrast across mask orientation. Another scheme, in which suppressive pooling followed compressive contrast responses to the mask components (e.g., oriented cortical cells), was ruled out by all of our data. We conclude that the different processes that underlie monoptic and dichoptic masking use the same type of contrast pooling within their respective suppressive fields, but the effects do not sum to predict the binocular case.

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Section: The Excitatory and Suppressive Exponents (P And Q)supporting

confidence: 81%

A common contrast pooling rule for suppression within and between the eyes

2008

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“…Visual inspection of the results suggests that the changes are similar to those expected by an increase in "contrast gain" (see Figure 1). Thus, to further characterize our results, average data for shock-paired and unpaired conditions were independently fit ( Figure 3A, solid and dashed lines) according to the Naka-Rushton contrast response model (Albrecht & Hamilton, 1982;Sclar et al, 1990):…”

Section: Resultsmentioning

confidence: 99%

Affective learning increases sensitivity to graded emotional faces.

Lim¹,

Pessoa²

2008

Emotion

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How does the affective significance of emotional faces affect perceptual decisions? We manipulated affective significance by pairing 100% fearful faces with aversive electrical stimulation and hypothesized that increasing the significance of a stimulus via its prior history would lead to enhanced processing. After fear conditioning, participants viewed graded emotional faces that ranged from neutral to fearful. Faces were shown either in a color that was previously paired with shock or a color not paired with shock during conditioning. Increases in the frequency of "fearful" responses for faces shown in the shock-paired color were most robust for faces at intermediate intensity levels (40 -60% fearful). Psychometric fits to the data revealed significant increased sensitivity for shock-paired relative to unpaired faces. Thus, despite identical physical features for shock-paired and unpaired stimuli (aside from the color, which was counterbalanced), more frequent (and faster) "fearful" responses were made when participants viewed affectively significant stimuli.

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“…This low contrast was selected in light of the finding that approximately half of the cells in the macaque extrastriate area MT have a semisaturation constant less than 7%, and a median exponent of 3.0 (Sclar et al, 1990). In the striate cortex of macaque, these values correspond to 33% and 2.4, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Velocity discrimination at higher stimulus speeds Single-unit recordings in area MT of the macaque indicate that these neurons respond optimally to high values of stimulus velocity (Maunsell and van Essen, 1983), and that their responses saturate at low levels of stimulus contrast (Sclar et al, 1990). …”

Section: Contrast Sensitivity To Drifting Gratingsmentioning

confidence: 99%

“…This evidence comes from anatomical (Spatz and Tigges, 1972;Spatz, 1977;Seltzer and Pandya, 1978;Ungerleider and Desimone, 1986;Boussaoud et al, 1990), neurophysiological (Maunsell and van Essen, 1983;Albright, 1984;Mikami et al, 1986a,b;Saito et al, 1986;Tanaka et al, 1986;Rodman and Albright, 1987;Snowden et al, 1992), and behavioral studies (Newsome et al, 1985;Newsome and Pare, 1988) in monkey brain. Selective destruction of pathways from parvo-and magnocellular laminae of the lateral geniculate nucleus in the thalamus suggest that, already at early stages of visual processing, information about the form and color of visual stimuli might be separated from information about motion and flicker (Maunsell et al, 1990;Schiller et al, 1990;Merigan et al, 1991). This evidence has led to the suggestion that information about stimulus form might follow a more ventral path from visual striate to inferotemporal cortex, whereas information about stimulus location and velocity might be processed along a more dorsal path, extending from the visual striate cortex, to the superio-temporal and parietal cortex (Ungerleider and Mishkin, 1982;Livingston andHubel, 1987, 1988).…”

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confidence: 99%

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Visual short-term memory of stimulus velocity in patients with unilateral posterior brain damage

Greenlee¹,

Lang²,

Mergner³

et al. 1995

J. Neurosci.

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Neurophysiological studies indicate the existence of an area in the extrastriate monkey cortex specialized for the processing of stimulus motion. The present investigation was conducted to determine whether a homologous area exits in the human cortex that underlies the processing and short-term storage of velocity information. Contrast detection and velocity discrimination thresholds were measured in a group of 23 patients with unilateral focal damage to either the lateral occipital, temporal, or posterior parietal cortex. Their results were compared to those of 23 age-matched control subjects. Detection and discrimination thresholds were determined for spatially truncated sinewave gratings presented 4 degrees eccentric of fixation randomly in either the left and right visual fields. Contrast detection thresholds were measured in a spatial two-alternative forced-choice paradigm for three different drift rates (1, 2, and 4 Hz) for leftward and rightward drift directions. Simultaneous velocity discrimination thresholds were determined for reference and test gratings presented 4 degrees left and right of fixation. Sequential velocity discrimination thresholds were measured using a delay, with a interstimulus interval (ISIs) of 1, 3, and 10 sec. In a subset of five patients with superior temporal lobe damage, spatial frequency discrimination thresholds for stationary gratings were also determined. The results indicate the following: (1) contrast detection thresholds for drifting gratings did not significantly differ between the patient and control groups; (2) velocity discrimination thresholds were significantly elevated in the patients; (3) velocity discrimination thresholds significantly increased with increasing ISI in the patients; (4) velocity discrimination thresholds were elevated most when the patients had a lesion in the superior temporal cortex; (5) in the subgroup of five patients with superior temporal lobe damage, spatial frequency discrimination thresholds were not significantly elevated. The results suggest that there is a visual area in the human posterior temporal cortex that is involved in the processing and short-term storage of the velocity of moving visual stimuli.

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Coding of image contrast in central visual pathways of the macaque monkey

Cited by 603 publications

References 36 publications

A common contrast pooling rule for suppression within and between the eyes

A common contrast pooling rule for suppression within and between the eyes

Affective learning increases sensitivity to graded emotional faces.

Visual short-term memory of stimulus velocity in patients with unilateral posterior brain damage

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