The major brain networks of human visual consciousness

Understanding consciousness is one of the most important and challenging questions in modern science. Existing theories have pursued single unifying mechanisms but do not succeed in explaining consciousness. Importantly, the neural circuits that distinguish messages that arrive from the outside world and attain consciousness have remained unknown. Here we identify signals throughout the entire brain at high spatiotemporal resolution specifically related to consciousness. To accomplish this, we combined a large sample size of electrical and neuroimaging data with a novel experimental approach to remove confounding signal unrelated to consciousness1-3. We discovered three major brain networks driving conscious visual perception. First, we found increases in signal detection regions in visual, fusiform cortex, and frontal eye fields; and in arousal/salience networks involving midbrain, thalamus, nucleus accumbens, anterior cingulate, and anterior insula. Second, we found increases in frontoparietal attention and executive control networks and in the cerebellum. Finally, we found decreases in the default mode network. Our results identify subcortical and cortical networks designed for signal detection, attentional amplification, and perceptual processing that together can explain visual consciousness. These findings provide evidence that understanding consciousness can be reframed as requiring multiple overlapping brain networks to produce consciousness of visual events4.

Effects of Moderate-to-Vigorous Acute Exercise on Visual Consciousness

Background the effect of acute exercise on cognition covers almost all stages of information processing, but few studies have focused on visual awareness. Subjective reports on the appearance of faint speed-changes in the perception of stimuli were used as an index for visual consciousness. Visual consciousness was assessed after exercise or rest. Aside from subjective index, objective speed-change discrimination was added as an index for the level of consciousness. Results: the results showed that subjective reports on the appearance of faint speed-changes in the perception of stimuli were affected by acute aerobic exercise. The hit rate for speed-change detection was marginally significantly higher after exercise than sedentary condition. Furthermore, the d’ index was higher after exercise. Analysis of the results obtained for the objective discrimination task showed that discrimination speed was boosted only when subjects were aware of the speed-change. Conclusions: these results suggest that acute exercise enhances visual consciousness.

V1 as an egocentric cognitive map

We typically distinguish between V1 as an egocentric perceptual map and the hippocampus as an allocentric cognitive map. In this article, we argue that V1 also functions as a post-perceptual egocentric cognitive map. We argue that three well-documented functions of V1, namely (i) the estimation of distance, (ii) the estimation of size, and (iii) multisensory integration, are better understood as post-perceptual cognitive inferences. This argument has two important implications. First, we argue that V1 must function as the neural correlates of the visual perception/cognition distinction and suggest how this can be accommodated by V1’s laminar structure. Second, we use this insight to propose a low-level account of visual consciousness in contrast to mid-level accounts (recurrent processing theory; integrated information theory) and higher-level accounts (higher-order thought; global workspace theory). Detection thresholds have been traditionally used to rule out such an approach, but we explain why it is a mistake to equate visibility (and therefore the presence/absence of visual experience) with detection thresholds.

Both high and low spatial frequencies are critical for visual consciousness in autism: Evidence of an emotional attentional blink paradigm.

High Spatial Frequencies (HSF - conveying local information) may serve a critical role in visual consciousness. Despite an HSF bias during visual perception in autism, autistic individuals demonstrate impairments in face processing. Our aim was to investigate the respective role of HSF and Low Spatial Frequencies (LSF - conveying coarse information) on visual consciousness in autism. Thirty-two autistic adults and 35 typically developing (TD) controls performed an emotional attentional blink paradigm with spatially filtered distractors. TD participants showed reduced T2 accuracy (i.e., accuracy for the second target given the correct report of the first target T1) after unfiltered and HSF distractors compared to LSF distractors. In the autistic group, we observed lower T2 accuracy than controls after HSF and LSF distractors but not after unfiltered distractors. Results suggest the importance of HSF for visual consciousness in TD participants whereas, both LSF and HSF seem important in autism.

Distrust Before First Sight: Knowledge- and Appearance-Based Effects of Trustworthiness on the Visual Consciousness of Faces

Not all visual stimuli processed by the brain reach the level of conscious perception. Previous research has shown that the emotional value of a stimulus is one of the factors that can affect whether it is consciously perceived. Here, we investigated whether social-affective knowledge influences a face’s chance to reach visual consciousness. Furthermore, we took into account the impact of facial appearance. Faces differing in facial trustworthiness (i.e., being perceived as more or less trustworthy based on appearance) were associated with neutral or negative socially relevant information. Subsequently, an attentional blink task was administered to examine whether the manipulated factors affect the faces’ chance to reach visual consciousness under conditions of reduced attentional resources. Participants showed enhanced detection of faces associated with negative as compared to neutral social information. In event-related potentials (ERPs), this was accompanied by effects in the time range of the early posterior negativity (EPN) component. These findings indicate that social-affective person knowledge is processed already before or during attentional selection and can affect which faces are prioritized for access to visual consciousness. In contrast, no clear evidence for an impact of facial trustworthiness during the attentional blink was found. This study was pre-registered using the Open Science Framework (OSF).

Graded Visual Consciousness During the Attentional Blink

One of the ongoing debates about visual consciousness is whether it can be considered as an all-or-none or a graded phenomenon. This may depend on the experimental paradigm and the task used to investigate this question. The present event-related potential study (N = 32) focuses on the attentional blink paradigm for which so far only little and mixed evidence is available. Detection of T2 face targets during the attentional blink was assessed via an objective accuracy measure (reporting the faces’ gender), subjective visibility on a perceptual awareness scale (PAS) as well as event-related potentials time-locked to T2 onset (components P1, N1, N2, and P3). The behavioral results indicate a graded rather than an all-or-none pattern of visual awareness. Corresponding graded differences in the N1, N2, and P3 components were observed for the comparison of visibility levels. These findings suggest that conscious perception during the attentional blink can occur in a graded fashion.

V1 as an Egocentric Cognitive Map

We typically distinguish between V1 as an egocentric perceptual map and the hippocampus as an allocentric cognitive map. In this article we explain why V1 also functions as an egocentric cognitive map. To the extent that cognitive processing has been discussed in V1, it has focused on (a) the allocation of attention, (b) top-down influences on perception, and (c) the transition from egocentric perception to allocentric navigation. By contrast, in this article we argue that three well-documented functions of V1, namely (a) the estimation of distance from eye position, (b) the estimation of size from eye position and/or pictorial cues, and (c) the multisensory integration of vision with proprioception and hearing, are potentially better understood as post-perceptual cognitive inferences. We use this insight to explore V1 as the neural correlates of the visual perception / cognition distinction, and propose a low-level account of visual consciousness in contrast to mid-level accounts (recurrent processing theory; integrated information theory), and higher-level accounts (higher-order thought; global workspace theory). We conclude by outlining the implications of our account for the perception of depth, motion, and colour / illumination.

No Evidence for a Single Oscillator Underlying Discrete Visual Percepts

Theories of perception based on discrete sampling posit that visual consciousness is reconstructed based on snapshot-like perceptual moments, as opposed to being updated continuously. According to a model proposed by Schneider (2018), discrete sampling can explain both the flash-lag and the Fröhlich illusion, whereby a lag in the conscious updating of a moving stimulus alters its perceived spatial location in comparison to a stationary stimulus. The alpha-band frequency, which is associated with phasic modulation of stimulus detection and the temporal resolution of perception, has been proposed to reflect the duration of perceptual moments. The goal of this study was to determine whether a single oscillator (e.g., alpha) is underlying the duration of perceptual moments, which would predict that the point of subjective equality (PSE) in the flash-lag and Fröhlich illusions are positively correlated across individuals. Although our displays induced robust flash-lag and Fröhlich effects, virtually zero correlation was seen between the PSE in the two illusions, indicating that the illusion magnitudes are unrelated across observers. These findings suggest that, if discrete sampling theory is true, these illusory percepts either rely on different oscillatory frequencies or not on oscillations at all. Alternatively, discrete sampling may not be the mechanism underlying these two motion illusions or our methods were ill-suited to test the theory.

NON-CLASSICAL SUBJECT OF VISION. PART II

The article is a continuation of the previous article Non-Classical Subject of Vision. Part I and is devoted to the analysis of the eventivity of a non-classical subject. The analysis of non-classical subjectivity in the article is based on the three-part mechanism of the power of distance, power of gaze and power of memory proposed by W. Benjamin. The concept of the image as a mediator through which the subject regains the lost distance with the world is discussed. The article deals with the concepts of the non-classical subject of visuality by J.-P. Sartre and G. Didi-Huberman as different types of transformation of the power of gaze and the role of memory in non-classical vision. Important elements of the concept of «scanty image» by J.-P. Sartre are analyzed: criticism of the naive understanding of the immanence of consciousness and the world, criticism of images as a weak copy of the object of observation, the development of a specific givenness of a thing in an image through its distant present absence. It is shown that the theory of «scanty image» breaks the unreal objects of visual consciousness and the sensually perceived world into two poles that are not connected with each other. Therefore, in Sartre’s concept, the relationship with the world — both in visual and sensory comprehension of reality, turns out to be problematic. In the theory of G. Didi-Huberman, built on the reorganization of the understanding of the aura in technically reproducible art, a deeper understanding of the image is given. The presence as well as the absence of things of the world do not appear as separate from each other, but turn out to be the dialectical unity of the game of near and far (Fort-Da). The article discusses this dialectical understanding of the relationship between the man and the world, which acts as an incessant rhythm of approaching and removing a visible object. In this eventful space of a vision (D. Joselit) turns a thing into a hybrid object, and the person appears as a flickering subject of vision.