Visibility, visual awareness, and visual masking of simple unattended targets are confined to areas in the occipital cortex beyond human V1/V2

Tse, Peter U.; Martinez-Conde, S.; Schlegel, Alexander; Macknik, Stephen L.

doi:10.1073/pnas.0508010102

Cited by 115 publications

(120 citation statements)

References 40 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…That and further work (Tse et al, 2005) indicated a late component to dichoptic masking that arises after binocular combination. Our results and arguments here do not challenge that conclusion, but Baker et al (2007b) proposed that the stimulus used in those studies probably involved processes that were different from the contrast phenomena here and elsewhere.…”

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

confidence: 86%

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

2008

View full text Add to dashboard Cite

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.

show abstract

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

confidence: 86%

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

2008

View full text Add to dashboard Cite

show abstract

“…Attention enhances the neural representation of target stimuli (Desimone and Duncan, 1995); it is considered a critical precursor for awareness by some (Driver and Mattingley, 1998;Dehaene et al, 2006) and a potential confound by others (Tse et al, 2005). Although the specific relationship between attention and consciousness remains unclear (Rees, 2007), it is evident that enhanced representation is not sufficient to produce awareness (Leopold and Logothetis, 1996).…”

Section: Discussionmentioning

confidence: 99%

Multiple Mechanisms of Consciousness: The Neural Correlates of Emotional Awareness

Amting¹,

Greening²,

Mitchell³

2010

J. Neurosci.

106

View full text Add to dashboard Cite

Emotional stimuli, including facial expressions, are thought to gain rapid and privileged access to processing resources in the brain. Despite this access, we are conscious of only a fraction of the myriad of emotion-related cues we face everyday. It remains unclear, therefore, what the relationship is between activity in neural regions associated with emotional representation and the phenomenological experience of emotional awareness. We used functional magnetic resonance imaging and binocular rivalry to delineate the neural correlates of awareness of conflicting emotional expressions in humans. Behaviorally, fearful faces were significantly more likely to be perceived than disgusted or neutral faces. Functionally,increasedactivitywasobservedinregionsassociatedwithfacialexpressionprocessing,includingtheamygdalaandfusiformgyrus during emotional awareness. In contrast, awareness of neutral faces and suppression of fearful faces were associated with increased activity in dorsolateral prefrontal and inferior parietal cortices. The amygdala showed increased functional connectivity with ventral visual system regions during fear awareness and increased connectivity with perigenual prefrontal cortex (pgPFC; Brodmann's area 32/10) when fear was suppressed. Despite being prioritized for awareness, emotional items were associated with reduced activity in areas considered critical for consciousness. Contributions to consciousness from bottom-up and top-down neural regions may be additive, such that increased activity in specialized regions within the extended ventral visual system may reduce demands on a frontoparietal system important for awareness. The possibility is raised that interactions between pgPFC and the amygdala, previously implicated in extinction, may also influence whether or not an emotional stimulus is accessible to consciousness.

show abstract

“…Other work performed by Macknik and his colleagues (Tse et al, 2005;Macknik and Martinez-Conde, 2004) used a very different type of stimulus in which the mask and test contained similar oriented contours, but were not superimposed in either space or time. In an imaging study on humans (Tse et al, 2005), and a single-cell study on monkey (Macknik and Martinez-Conde, 2004), Macknik drew the opposite conclusion from us: that dichoptic influences arise after binocular summation. Our scheme (Fig.…”

Section: Implications and Comparison With Other Studiesmentioning

confidence: 99%

Psychophysical evidence for two routes to suppression before binocular summation of signals in human vision

2007

View full text Add to dashboard Cite

Abstract-Visual mechanisms in primary visual cortex are suppressed by the superposition of gratings perpendicular to their preferred orientations. A clear picture of this process is needed to (i) inform functional architecture of image-processing models, (ii) identify the pathways available to support binocular rivalry, and (iii) generally advance our understanding of early vision. Here we use monoptic sine-wave gratings and cross-orientation masking (XOM) to reveal two crossoriented suppressive pathways in humans, both of which occur before full binocular summation of signals. One is a within-eye (ipsiocular) pathway that is spatially broadband, immune to contrast adaptation and has a suppressive weight that tends to decrease with stimulus duration. The other pathway operates between the eyes (interocular), is spatially tuned, desensitizes with contrast adaptation and has a suppressive weight that increases with stimulus duration. When cross-oriented masks are presented to both eyes, masking is enhanced or diminished for conditions in which either ipsiocular or interocular pathways dominate masking, respectively. We propose that ipsiocular suppression precedes the influence of interocular suppression and tentatively associate the two effects with the lateral geniculate nucleus (or retina) and the visual cortex respectively. The interocular route is a good candidate for the initial pathway involved in binocular rivalry and predicts that interocular cross-orientation suppression should be found in cortical cells with predominantly ipsiocular drive.

show abstract

Visibility, visual awareness, and visual masking of simple unattended targets are confined to areas in the occipital cortex beyond human V1/V2

Cited by 115 publications

References 40 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

Multiple Mechanisms of Consciousness: The Neural Correlates of Emotional Awareness

Psychophysical evidence for two routes to suppression before binocular summation of signals in human vision

Contact Info

Product

Resources

About