Setting the Stage for the Inner Journey: Unraveling the Interplay of Contextual Factors and the Intensity of Psychedelic-Induced Ego Dissolution.

Psychedelics have the potential to induce profound alterations in cognition, emotionality, and sensory perception. The quality and intensity of these subjective effects exhibit high intra- and inter-individual variability, which can potentially be accounted for by the variability in contexts in which psychedelics are used. Therefore, the aim of the present cross-sectional study was to investigate how internal and external contextual factors are related to the subjective intensity of psychedelic-induced ego dissolution experiences.

Processing of self-related thoughts in experienced users of classic psychedelics: A source localisation EEG study.

Background: Psychedelics have gained increasing interest in scientific research due to their ability to induce profound alterations in perception, emotional processing and self-consciousness. However, the research regarding the functioning of individuals who use psychedelics in naturalistic contexts remains limited.

Aims: Here we aim to explore psychological and neurophysiological differences between naturalistic psychedelics users and non-users in terms of processing of self-related thoughts.

The influence of spatial and temporal attention on visual awareness-a behavioral and ERP study.

Whether attention is a prerequisite of perceptual awareness or an independent and dissociable process remains a matter of debate. Importantly, understanding the relation between attention and awareness is probably not possible without taking into account the fact that both are heterogeneous and multifaceted mechanisms. Therefore, the present study tested the impact on visual awareness of two attentional mechanisms proposed by the Posner model: temporal alerting and spatio-temporal orienting.

Naturalistic use of psychedelics does not modulate processing of self-related stimuli (but it might modulate attentional mechanisms): An event-related potentials study.

Classic psychedelics are able to profoundly alter the state of consciousness and lead to acute experiences of ego dissolution - the blurring of the distinction between representations of self and the external world. However, whether repeated use of psychedelics is associated with more prolonged and permanent modifications to the concept of self remains to be investigated. Therefore, we conducted a preregistered, cross-sectional study in which experienced psychedelics users (15 or more lifetime experiences with psychedelics; N = 56) were compared to nonusers (N = 57) in terms of neural reactivity to a Self-name (i.

Early Electrophysiological Correlates of Perceptual Consciousness Are Affected by Both Exogenous and Endogenous Attention.

It has been proposed that visual awareness negativity (VAN), which is an early ERP component, constitutes a neural correlate of visual consciousness that is independent of perceptual and cognitive mechanisms. In the present study, we investigated whether VAN is indeed a specific marker of phenomenal awareness or rather reflects the involvement of attention. To this end, we reanalyzed data collected in a previously published EEG experiment in which awareness of visual stimuli and two aspects that define attentional involvement, namely, the inherent saliency and task relevance of a stimulus, were manipulated orthogonally.

The relation between naturalistic use of psychedelics and perception of emotional stimuli: An event-related potential study comparing non-users and experienced users of classic psychedelics.

Background: Previous research has suggested that controlled administration of psychedelic substances can modulate emotional reactivity, enhancing positive and diminishing negative emotions. However, it is unclear whether similar effects are associated with using psychedelics in less-controlled naturalistic environments.

Aims: This cross-sectional study investigated the neural markers associated with the perception of emotional stimuli in individuals with extensive experience of naturalistic psychedelic use (15 or more lifetime experiences), comparing them to non-users.

I focus only when I see your fear-fearful faces are not prioritized by attention when processed outside of awareness.

The defensive reaction to threats consists of two components: non-specific physiological arousal and specific attentional prioritization of the threatening stimulus, both of which are assumed by the so-called "low-road" hypothesis to be induced automatically and unconsciously. Although ample evidence indicates that non-specific arousal can indeed be caused by unconscious threatening stimuli, data regarding the involvement of the attentional selection mechanism remain inconclusive. Therefore, in the present study we used ERPs to compare the potential engagement of attention in the perception of subliminal and supraliminal fearful facial expressions to that of neutral ones.

Sensory modality defines the relation between EEG Lempel-Ziv diversity and meaningfulness of a stimulus.

Diversity of brain activity is a robust neural correlate of global states of consciousness. It has been proposed that diversity measures specifically reflect the temporal variability of conscious experience. Previous studies supported this hypothesis by showing that perception of meaningful visual stimuli causes richer, more-variable experiences than perception of meaningless stimuli, and this is reflected in greater brain signal diversity.

Attentional Prioritization of Complex, Naturalistic Stimuli Maintained in Working-Memory-A Dot-Probe Event-Related Potentials Study.

Recent studies suggest that a stimulus actively maintained in working memory (WM) automatically captures visual attention when subsequently perceived. Such a WM-based guidance effect has been consistently observed for stimuli defined by simple features, such as color or orientation, but studies using more complex stimuli provided inconclusive results. Therefore, we investigated whether the WM-based guidance effect occurs also for naturalistic stimuli, whose identity is defined by multiple features and relations among them, specifically for faces and houses.

Naturalistic use of psychedelics is related to emotional reactivity and self-consciousness: The mediating role of ego-dissolution and mystical experiences.

Background: Psychedelics are able to acutely alter emotional reactivity and self-consciousness. However, whether the regular naturalistic use of psychedelics can be linked to more persistent trait-level changes in these domains remains an open question.

Aim: To test the hypotheses that (1) using psychedelics is related to higher positive and lower negative emotional reactivity; and (2) an adaptive pattern of self-consciousness, including diminished public self-consciousness and rumination, and increased reflection and self-awareness; and (3) these relations are mediated by the intensity of past ego-dissolution and mystical experiences.

Perception of semantic relations in scenes: A registered report study of attention hold.

To what extent the semantic relations present in scenes guide spatial attention automatically remains a matter of debate. Considering that spatial attention can be understood as a sequence of shifts, engagements, and disengagements, semantic relations might affect each stage of this process differently. Therefore, we investigated whether objects that violate semantic rules engage attention for longer than objects that are expected in a given context.

The forest, the trees, or both? Hierarchy and interactions between gist and object processing during perception of real-world scenes.

The global-to-local theories of perception assume that the gist of a scene is computed early and automatically, whereas recognition of objects occurs at a later processing stage, requires attentional resources, and is primed by the representation of gist. To test these theoretical predictions, we investigated the processing hierarchy of gist- and object-recognition and their interaction in two experiments (total N = 60). Backward-masked images of real-world scenes were presented for a range of brief durations - between 8 ms and 100 ms, and participants performed either an object or a background classification task, in separate blocks.

The self-face captures attention without consciousness: Evidence from the N2pc ERP component analysis.

It is well established that stimuli representing or associated with ourselves, like our own name or an image of our own face, benefit from preferential processing. However, two key questions concerning the self-prioritization mechanism remain to be addressed. First, does it operate in an automatic manner during the early processing, or rather in a more controlled fashion at later processing stages? Second, is it specific to the self-related stimuli, or can it be activated also by other stimuli that are familiar or salient? We conducted a dot-probe experiment to investigate the mechanism behind the attentional prioritization of the self-face image and to tackle both questions.

Unconscious perception of one's own name modulates amplitude of the P3B ERP component.

The P3 event-related potential has been known for over 50 years, but its function is still a matter of ongoing debate. Current theories interpret P3b either as a correlate of perceptual consciousness, or as reflecting cognitive processes, like working memory and executive functions. Unexpectedly, recent studies indicate that P3b might occur in response to unconsciously presented stimuli which, if further replicated, will be important for defining its functional role.

Automatic Attention Capture by Threatening, But Not by Semantically Incongruent Natural Scene Images.

Visual objects are typically perceived as parts of an entire visual scene, and the scene's context provides information crucial in the object recognition process. Fundamental insights into the mechanisms of context-object integration have come from research on semantically incongruent objects, which are defined as objects with a very low probability of occurring in a given context. However, the role of attention in processing of the context-object mismatch remains unclear, with some studies providing evidence in favor, but other against an automatic capture of attention by incongruent objects.

Unconscious Detection of One's Own Image.

A key mechanism behind preferential processing of self-related information might be an early and automatic capture of attention. Therefore, the present study tested a hypothesis that one's own face will attract bottom-up attention even without conscious identification. To test this, we used a dot-probe paradigm with electrophysiological recordings, in which participants ( N = 18) viewed masked and unmasked pairs of faces (other, self) presented laterally.

Informativeness of Auditory Stimuli Does Not Affect EEG Signal Diversity.

Brain signal diversity constitutes a robust neuronal marker of the global states of consciousness. It has been demonstrated that, in comparison to the resting wakefulness, signal diversity is lower during unconscious states, and higher during psychedelic states. A plausible interpretation of these findings is that the neuronal diversity corresponds to the diversity of subjective conscious experiences.

The impact of self-esteem on the preferential processing of self-related information: Electrophysiological correlates of explicit self vs. other evaluation.

Preferential processing of self-related information is a well-documented phenomenon on both the behavioral and neural levels. However, the impact of self-esteem on this self-preference has not been studied in a systematic way. Here, the electrophysiological correlates of explicit self-reflection were investigated in individuals with low (LSE) and high self-esteem (HSE).

Exposure to attachment narratives dynamically modulates cortical arousal during the resting state in the listener.

Background: Affective stimulation entails changes in brain network patterns at rest, but it is unknown whether exogenous emotional stimulation has a prolonged effect on the temporal dynamics of endogenous cortical arousal. We therefore investigated differences in cortical arousal in the listener following stimulation with different attachment-related narratives.

Methods: Resting-state EEG was recorded from sixteen healthy subjects for ten minutes each with eyes closed: first at baseline and then after passively listening to three affective narratives from strangers about their early childhood experiences (prototypical for insecure-dismissing, insecure-preoccupied, and secure attachment).

Loss of consciousness is related to hyper-correlated gamma-band activity in anesthetized macaques and sleeping humans.

Loss of consciousness can result from a wide range of causes, including natural sleep and pharmacologically induced anesthesia. Important insights might thus come from identifying neuronal mechanisms of loss and re-emergence of consciousness independent of a specific manipulation. Therefore, to seek neuronal signatures of loss of consciousness common to sleep and anesthesia we analyzed spontaneous electrophysiological activity recorded in two experiments.

Breakdown of long-range temporal correlations in brain oscillations during general anesthesia.

Consciousness has been hypothesized to emerge from complex neuronal dynamics, which prevails when brain operates in a critical state. Evidence supporting this hypothesis comes mainly from studies investigating neuronal activity on a short time-scale of seconds. However, a key aspect of criticality is presence of scale-free temporal dependencies occurring across a wide range of time-scales.

Alternating Current Stimulation for Vision Restoration after Optic Nerve Damage: A Randomized Clinical Trial.

Background: Vision loss after optic neuropathy is considered irreversible. Here, repetitive transorbital alternating current stimulation (rtACS) was applied in partially blind patients with the goal of activating their residual vision.

Methods: We conducted a multicenter, prospective, randomized, double-blind, sham-controlled trial in an ambulatory setting with daily application of rtACS (n = 45) or sham-stimulation (n = 37) for 50 min for a duration of 10 week days.

Non-invasive electric current stimulation for restoration of vision after unilateral occipital stroke.

Occipital stroke often leads to visual field loss, for which no effective treatment exists. Little is known about the potential of non-invasive electric current stimulation to ameliorate visual functions in patients suffering from unilateral occipital stroke. One reason is the traditional thinking that visual field loss after brain lesions is permanent.