Visual awareness negativity is an early neural correlate of awareness: A preregistered study with two Gabor sizes

Eklund, Rasmus; Wiens, Stefan

doi:10.3758/s13415-018-0562-z

Cited by 41 publications

(39 citation statements)

References 37 publications

(90 reference statements)

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“…Thus, our results suggest that VAN correlates with visual awareness. Our finding was consistent with previous studies (Wilenius-emet et al, 2004; Rutiku et al, 2015; Koivisto and Grassini, 2016; Eklund and Wiens, 2018), which suggested that VAN was an early electrophysiological correlate of visual awareness.…”

Section: Discussionsupporting

confidence: 94%

Later Positivity Reflects Post-perceptual Processes: Evidence From Immediate Detection and Delayed Detection Tasks

Lyu

2019

Front. Psychol.

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Electrophysiological recordings are usually used to study neural correlates of consciousness (NCCs). The aim of our present study was to use two detection tasks to dissociate the electrophysiological correlates of visual awareness from the post-perceptual processes. In immediate detection task, participants had to quickly report whether the stimulus was presented after stimulus, whereas in delayed detection task, participants had to put off reporting whether the stimulus was presented after stimulus. The results showed that two previously frequently observed electrophysiological NCCs were observed: visual awareness negativity (VAN) and later positivity (LP). Importantly, the amplitude of VAN over posterior temporal and occipital areas was not influenced by the task manipulation. However, the amplitude of LP over parietal, posterior temporal and occipital areas was influenced by the task manipulation during 650–850 ms. These data suggest that VAN is an early electrophysiological correlates of visual awareness, and LP reflects post-perceptual processes required in reporting perceptual awareness.

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Section: Discussionsupporting

confidence: 94%

Later Positivity Reflects Post-perceptual Processes: Evidence From Immediate Detection and Delayed Detection Tasks

Lyu

2019

Front. Psychol.

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“…Similarly, there was a significant N2 difference between aware and unaware trials over posterior temporal and occipital electrodes. According previous studies (e.g., Wilenius-emet et al, 2004; Rutiku et al, 2015; Koivisto et al, 2016; Koivisto and Grassini, 2016; Eklund and Wiens, 2018), this significant negative amplitude difference between aware and unaware conditions in N1–N2 latency range over posterior temporal and occipital electrodes is commonly known as VAN. With respect to VAN, our result is somewhat different from previous null results (Lamy et al, 2009; Salti et al, 2012).…”

Section: Discussionmentioning

confidence: 77%

“…VAN is the negative amplitude difference between aware and unaware conditions (Koivisto and Revonsuo, 2010; Railo et al, 2011). It typically appears around 200 ms (N1–N2 latency range or N200) in posterior temporal and occipital electrodes (Railo et al, 2011; Koivisto et al, 2016, 2017; Koivisto and Grassini, 2016; Eklund and Wiens, 2018). LP is the positive amplitude difference between aware and unaware condition in the P3 time window (Koivisto and Revonsuo, 2010; Railo et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

The P3 Reflects Awareness and Can Be Modulated by Confidence

Lyu

Sclodnick

et al. 2019

Front. Neurosci.

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An important question in neural correlate of consciousness (NCC) studies is whether event-related potential (ERP) component P3 reflects visual awareness or the confidence with which one reports a visual experience. In the present study, participants detected visual stimuli presented at threshold-level contrast, then rated their subjective confidence with respect to their response on a four-point scale (very confident, quite confident, slightly confident, and not confident at all). Because awareness responses in trials with rating of “not confident at all” were likely noise, we analyzed the data excluding those trials. The ERP results revealed a significant positive difference in P3 amplitude between “aware” and “unaware” trials. P3 amplitude was more positive in aware trials compared to unaware trials. Importantly, this pattern was observed for trials with combined confidence ratings of “very confident” and “quite confident,” and for trials with confidence ratings of “slightly confident,” suggesting that awareness alone can modulate P3. A significant interaction between awareness and confidence is reported, suggesting that confidence influences P3 as well. In addition, ERP results revealed that visual awareness negativity (VAN) was observed over posterior temporal and occipital electrodes and largely not influenced by confidence. This result indicated that VAN is an early neural correlate of visual awareness.

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“…Mainly, they can be classified as “early” or “late” theories of visual awareness depending on the temporal window considered to be critical for the emergence of awareness. Some studies have identified VAN as the earliest neural marker of visual awareness, fueling the idea that LP is more related to further post-perceptual processing rather than to conscious perception per se (Koivisto and Revonsuo, 2003 , 2010 ; Wilenius-Emet et al, 2004 ; Pitts et al, 2014 ; Koivisto and Grassini, 2016 ; Koivisto et al, 2016 ; Eklund and Wiens, 2018 ; Mazzi et al, 2019 ; Ye and Lyu, 2019 ). Other evidence flowing into the late theories of visual awareness, usually endorsing the global workspace theory as well, have indicated that LP, instead, could represent the ERP component giving rise to conscious perception (Sergent et al, 2005 ; Babiloni et al, 2006 ; Del Cul et al, 2007 ; Lamy et al, 2009 ; Dehaene and Changeux, 2011 ; Salti et al, 2012 ; Boncompte and Cosmelli, 2018 ).…”

Section: Discussionmentioning

confidence: 99%

Late Positivity Does Not Meet the Criteria to be Considered a Proper Neural Correlate of Perceptual Awareness

Mazzi

Mazzeo

Savazzi

2020

Front. Syst. Neurosci.

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Contrastive analysis has been widely employed in the search for the electrophysiological neural correlates of consciousness. However, despite its clear logic, it has been argued that it may not succeed in isolating neural processes solely involved in the emergence of perceptual awareness. In fact, data from contrastive analysis would be contaminated by potential confounding factors reflecting distinct, though related, processes either preceding or following the conscious perception. At present, the ERP components representing the proper correlates of perceptual awareness still remain to be identified among those correlating with awareness (i.e., Visual Awareness Negativity, VAN and Late Positivity, LP). In order to dissociate visual awareness from post-perceptual confounds specifically related to decision making, we manipulated the response criterion, which affects how a percept is translated into a decision. In particular, while performing an orientation discrimination task, participants were asked to shift their response criterion across sessions. As a consequence, the resulting modulation should concern the ERP component(s) not exclusively reflecting mechanisms regulating the subjective conscious experience itself but rather the processes accompanying it. Electrophysiological results showed that N1 and P3 were sensitive to the response criterion adopted by participants. Additionally, the more the participants shifted their response criterion, the bigger the ERP modulation was; this was consequently indicative of the critical role of these components in the decision-making processes regardless of awareness level. When considering data independently from the response criterion, the aware vs. unaware contrast showed that both VAN and LP were significant. Crucially, the LP component was also modulated by the interaction of awareness and response criterion, while VAN results to be unaffected. In agreement with previous literature, these findings provide evidence supporting the hypothesis that VAN tracks the emergence of visual awareness by encoding the conscious percept, whereas LP reflects the contribution from post-perceptual processes related to response requirements. This excludes a direct functional role of this later component in giving rise to perceptual awareness.

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Visual awareness negativity is an early neural correlate of awareness: A preregistered study with two Gabor sizes

Cited by 41 publications

References 37 publications

Later Positivity Reflects Post-perceptual Processes: Evidence From Immediate Detection and Delayed Detection Tasks

Later Positivity Reflects Post-perceptual Processes: Evidence From Immediate Detection and Delayed Detection Tasks

The P3 Reflects Awareness and Can Be Modulated by Confidence

Late Positivity Does Not Meet the Criteria to be Considered a Proper Neural Correlate of Perceptual Awareness

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