Diffusion model-based understanding of subliminal affective priming in continuous flash suppression.
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ABSTRACT:
SUBMITTER: Kim M
PROVIDER: S-EPMC8169665 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Continuous flash suppression (CFS) has become a popular tool for studying unconscious processing, but the level at which unconscious processing of visual stimuli occurs under CFS is not clear. Response priming is a robust and well-understood phenomenon, in which the prime stimulus facilitates overt responses to targets if the prime and target are associated with the same response. We used CFS to study unconscious response priming of shape: arrows with left or right orientation served as primes and targets. The prime was presented near the limen of consciousness and each trial was followed by subjective rating of visibility and a forced-choice response concerning the orientation of the prime in counterbalanced order. In trials without any reported awareness of the presence of the prime, discrimination of the prime's orientation was at chance level. However, priming was elicited in such unconscious trials. Unconscious priming was not influenced by the prime-target onset-asynchrony (SOA)/prime duration, whereas conscious processing, as indicated by the enhanced discriminability of the prime's orientation and conscious priming, increased at the longest SOAs/prime durations. These results show that conscious and unconscious processes can be dissociated with CFS and that CFS-masking does not completely suppress unconscious visual processing of shape.
| S-EPMC5798817 | biostudies-literature
Project description:Whether unconscious complex visual information integration occurs over time remains largely unknown and highly controversial. Previous studies have tended to use a combination of strong masking or suppression and a weak stimulus signal (e.g., low luminance), resulting in a low signal-to-noise ratio during unconscious stimulus presentation. To lengthen the stimulus exposure, we introduced intermittent presentation into interocular suppression. This discontinuous suppression allowed us to insert a word during each suppression period and deliver multiple words over time unconsciously. We found that, after participants received the subliminal context, they responded faster to a syntactically incongruent target word in a lexical decision task. We later replicated the finding in a separate experiment where participants exhibited chance performance on locating the subliminal context. These results confirmed that the sentential context was both subjectively and objectively subliminal. Critically, the effect disappeared when the context was disrupted by presenting only partial sentences or sentences with a reversed word order. These control experiments showed that the effect was not merely driven by word-word association but instead required integration over multiple words in the correct order. These findings support the possibility of unconscious high-level, complex information integration.
| S-EPMC8164368 | biostudies-literature
Project description:IntroductionSubliminal affective priming effects (SAPEs) refer to the phenomenon by which the presentation of an affective prime stimulus influences the subsequent affective evaluation of a target stimulus. Previous studies have reported that unconsciously processed stimuli affect behavioral performance more than consciously processed stimuli. However, the impact of SAPEs on the face-specific N170 component is unclear. We studied how SAPEs for fearful faces affected the N170 for subsequent supraliminal target faces using event-related potentials (ERPs).MethodsJapanese adults (n = 44, 20 females) participated in this study. Subliminal prime faces (neutral or fearful) were presented for 17 ms, followed by a backward mask for 283 ms and 800 ms target faces (neutral, emotionally ambiguous, or fearful). 128-channel ERPs were recorded while participants judged the expression of target faces as neutral or fearful. Response rates and response times were also measured for assessing behavioral alterations.ResultsAlthough the behavioral results revealed no evidence of SAPEs, we found gender-related SAPEs in right N170 amplitude. Specifically, female participants exhibited enhanced right N170 amplitude for emotionally neutral faces primed by fearful faces, while male participants exhibited decreased N170 amplitude in fearful prime trials with fearful target faces. Male participants exhibited significant correlations between N170 amplitude and behavioral response time in the fearful prime-neutral target condition.ConclusionsOur ERP results suggest the existence of a gender difference in target-face processing preceded by subliminally presented face stimuli in the right occipito-temporal region.
| S-EPMC8035456 | biostudies-literature
Project description:Research on visual rivalry has demonstrated that consecutive dominance durations are serially dependent, implying that the underlying competition mechanism is not driven by some random process but includes a memory component. Here we asked whether serial dependence is also observed in continuous flash suppression (CFS). We addressed this question by analyzing a large dataset of time series of suppression durations obtained in a series of so-called "breaking CFS" experiments in which the duration of the period is measured until a suppressed target breaks through the CFS mask. Across experimental manipulations, stimuli, and observers, we found that (i) the distribution of breakthrough rates was fit less well by a gamma distribution than in conventional visual rivalry paradigms, (ii) the suppression duration on a previous trial influenced the suppression duration on a later trial up to as long as a lag of eight trials, and (iii) the mechanism underlying these serial correlations was predominantly monocular. We conclude that the underlying competition mechanism of CFS also includes a memory component that is primarily, but not necessarily exclusively, monocular in nature. We suggest that the temporal dependency structure of suppression durations in CFS is akin to those observed in binocular rivalry, which might imply that both phenomena tap into similar rather than distinct mechanisms.
| S-EPMC6307532 | biostudies-literature
Project description:One notion emerging from studies on unconscious visual processing is that different "blinding techniques" seem to suppress the conscious perception of stimuli at different levels of the neurocognitive architecture. However, even when only the results from a single suppression method are compared, the picture of the scope and limits of unconscious visual processing remains strikingly heterogeneous, as in the case of continuous flash suppression (CFS). To resolve this issue, it has been suggested that high-level semantic processing under CFS is facilitated whenever interocular suppression is attenuated by the removal of visuospatial attention. In this behavioral study, we aimed to further investigate this "CFS-attenuation-by-inattention" hypothesis in a numerical priming study using spatial cueing. Participants performed a number comparison task on a visible target number ("compare number to five"). Prime-target pairs were either congruent (both numbers smaller, or both larger than five) or incongruent. Based on the "CFS-attenuation-by-inattention" hypothesis, we predicted that reaction times (RTs) for congruent prime-target pairs should be faster than for incongruent ones, but only when the prime was presented at the uncued location. In the invisible condition, we observed no priming effects and thus no evidence in support of the "CFS-attenuation-by-inattention" hypothesis. In the visible condition, we found an inverse effect of prime-target congruency. Our results agree with the notion that the representation of CF-suppressed stimuli is fractionated, and limited to their basic, elemental features, thus precluding semantic processing.
| S-EPMC9828280 | biostudies-literature
Project description:Continuous flash suppression (CFS) refers to a technique to render a monocular stimulus invisible by presenting a dynamic series of high-contrast patterns (such as Mondrian patterns) to the other eye. Despite its popularity as a tool to suppress stimulus from awareness, the suppression mechanisms underlying CFS remain not well understood. To further elucidate the suppression mechanisms, this study investigated the effects of eye swapping on CFS suppression by manipulating the eye of presentation of the suppressor and the target. Results showed that eye swapping of the suppressor and the target significantly reduced the strength of CFS suppression when swapping frequency was higher (3.5 Hz). However, strong suppression persisted at lower swapping frequency (1.2 Hz). Investigation of the time course of suppression revealed that suppression was weaker just after eye swapping but that it quickly regained strength over the monocular presentation period of the suppressor. However, this buildup seemed to not be fast enough to closely follow eye swapping at higher frequency. These findings can be better understood by the contribution of monocular processes to CFS suppression. They imply that interocular suppression caused by competition between monocular processes can mediate phenomenal suppression over multiple eye swaps when swapping frequency is low. The significance of the findings is discussed in relation to binocular rivalry and binocular switch suppression.
| S-EPMC7401929 | biostudies-literature
Project description:Continuous flash suppression (CFS) entails presentation of a stationary target to one eye and an animated sequence of arrays of geometric figures, the mask, to the other eye. The prototypical CFS sequence comprises different sized rectangles of various colors, dubbed Mondrians. Presented as a rapid, changing sequence to one eye, Mondrians or other similarly constructed textured arrays can abolish awareness of the target viewed by the other eye for many seconds at a time, producing target suppression durations much longer than those associated with conventional binocular rivalry. We have devised an animation technique that replaces meaningless Mondrian figures with recognizable visual objects and scenes as inducers of CFS, allowing explicit manipulation of the visual semantic content of those masks. By converting each image of these CFS sequences into successively presented objects or scenes each comprised of many small, circular patches of color, we create pointillist CFS sequences closely matched in terms of their spatio-temporal power spectra. Randomly rearranging the positions of the pointillist patches scrambles the images so they are no longer recognizable. CFS sequences comprising a stream of different objects produces more robust interocular suppression than do sequences comprising a stream of different scenes, even when the two categories of CFS are matched in root mean square contrast and spatial frequency content. Factors promoting these differences in CFS potency could range from low-level, image-based features to high-level factors including attention and recognizability. At the same time, object- and scene-based CFS sequences, when themselves suppressed from awareness, do not differ in their durations of suppression, implying that semantic content of those images comprising CFS sequences are not registered during suppression. The pointillist technique itself offers a potentially useful means for examining the impact of high-level image meaning on aspects of visual perception other than interocular suppression.
| S-EPMC6886724 | biostudies-literature
Project description:Previous studies have demonstrated the automatic vigilance effect for faces and pictures and have attributed it to the brain's prioritized unconscious evaluation of early evolutionary stimuli that are critical to survival. Whether this effect exists for evolutionarily more recent stimuli, such as written words, has become the center of much debate. Apparently contradicting results have been reported in different languages, such as Hebrew, English, and Traditional Chinese (TC), with regard to the unconscious processing of emotional words in breaking continuous flash suppression (b-CFS). Our current study used two experiments (with two-character words or single-character words) to verify whether the emotional valence or the length of Simplified Chinese (SC) words would modulate conscious access in b-CFS. We failed to replicate the findings reported in Yang and Yeh (2011) using TC, but found that complex high-level emotional information could not be extracted from interocularly suppressed words regardless of their length. Our findings comply with the distinction between subliminal and preconscious states in Global Neuronal Workspace Theory and support the current notion that preconsciousness or partial awareness may be indispensable for high-level cognitive tasks such as reading comprehension.
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Project description:Prediction of the rate and extent of drug absorption upon oral dosing needs models that capture the complexities of both the drug molecule and intestinal physiology. We report here the development of a continuous intestinal absorption model based on the convection-diffusion equation. The model includes explicit enterocyte apical membrane and intracellular lipid radial compartments along the length of the intestine. Physiologic functions along length x are built into the model and include velocity, diffusion, surface areas, and pH of the intestine. Also included are expression levels of the intestinal active uptake transporter OATP2B1 and efflux transporter P-gp. Oral dosing of solution as well as solid (with a dissolution function) was modeled for several drugs. The fraction absorbed (FA) and concentration-time (C-t) profiles were predicted and compared with clinical data. Overall, FA was well predicted upon oral (n = 21) or colonic dosing (n = 11), with four outliers. The overall accuracy (prediction of the correct bin) was 81% with outliers and 90% without outliers. Of the nine solution dosing data sets, six drugs were very well predicted with an exposure overlap coefficient (EOC) > 0.9 and predicted Cmax and Tmax values similar to those observed. Of the six solid dose formulations evaluated, the EOC values were > 0.9 for all drugs except budesonide. The observed precipitation of nifedipine at high doses was predicted by the model. Most of the poor predictions were for drugs that are known to be transporter substrates. As proof of concept, incorporating OATP2B1 and P-gp markedly improved the EOC and predicted Cmax and Tmax for fexofenadine. Finally, the continuous intestinal model accurately recapitulated the known relationships between drug absorption and permeability, solubility, and particle size. Together, these results indicate that this preliminary intestinal absorption model offers a simple and straightforward framework to build in complexities such as drug permeability, lipid partitioning, solubility, metabolism, and transport for improved prediction of the rate and extent of drug absorption.
| S-EPMC5627780 | biostudies-literature
Project description:In continuous flash suppression (CFS), a dynamic sequence of Mondrian patterns presented to one eye suppresses a static target in the other eye for several seconds at a time. Its effectiveness has been linked to low-level properties such as spatial frequency and orientation, but the role of higher order influences remains unstudied. Here, using a tracking paradigm, we asked if the spatial and temporal predictability of the Mondrian sequence affects CFS dynamics. Predictable temporal sequences were regularly updated every 100 ms or modulated sinusoidally in pixel luminance at 2 Hz. Unpredictable temporal sequences were irregularly updated or had stochastic pixel luminance changes across time. To vary spatial predictability, sequences were either updated with different Mondrian patterns or had a fixed spatial pattern. We found a modest effect of spatial uncertainty when the target modulation was low (0.125 Hz) but not temporal uncertainty, which had no significant effects regardless of target modulation. Similar results were obtained when we pitted the standard Mondrian sequence against sequences with a fixed spatial pattern and temporally low-pass filtered sequences in a binocular rivalry paradigm. Thus, not only was the effect of information predictability was modest and spatial, but it was also dependent on the presence of higher temporal frequencies. Together, the results demonstrate the significance of low-level properties in affecting CFS dynamics and the possible involvement of pattern structure masking in CFS.
| S-EPMC6108022 | biostudies-literature