Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness

Schwartzman, David J.; Schartner, Michael; Ador, Benjamin B; Simonelli, Francesca; Chang, Acer; Seth, Anil K.

doi:10.1101/511766

Cited by 23 publications

(71 citation statements)

References 62 publications

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“…It is equipped with one halogen lamp which is used for constant light stimulation and eight LEDs to apply FLS with high precision in timing and luminance via a programmable interface. Three light stimulation conditions with a duration of 20 minutes each were used: (1) Constant light stimulation as full intensity halogen light, (2) 3 Hz and (3) 10 Hz flicker stimulation as 50% ON/OFF times of LED light, as applied in Schwartzman et al (2019).…”

Section: Methodsmentioning

confidence: 99%

“…FLS is a non-pharmacological method to induce short-term consciousness alterations by stimulating the (typically closed) eyes with stroboscopic, flickering light. FLS is especially associated with hallucinatory perceptions of colors and geometric patterns (Allefeld, Pütz, Kastner, & Wackermann, 2011;Schwartzman et al, 2019). Flicker frequencies between 5 Hz and 30 Hz have been reported to invoke flicker-induced visual hallucinations (FIVHs) whose content participants are not able to volitionally control (Ffytche, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…However, frequencies between 8 Hz and 12 Hzin the EEG alpha frequency rangetend to evoke the most intense FIVHs (Mauro, Raffone, & VanRullen, 2015). FLS is also known to cause intense and diverse subjective experiences, as well as an increase in neural signal diversity (Schwartzman et al, 2019). Regarding the phenomenology of subjective experiences, Ludwig (1966) e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Such a systematic quantification enables comparisons with the subjective effects evoked by other ASCs induction methods (for further information see the Altered States Database; Schmidt & Berkemeyer, 2018). Though many ASC induction methods have been investigated in a structured manner, there have been few studies focusing on ASCs evoked by FLS (Schwartzman et al, 2019). Hence, the main aim of the present study was to structurally assess the phenomenology of subjectively perceived experiences during FLS-induced ASCs by applying established tools and questionnaires to enable a comparison with other induction methods (Schmidt & Berkemeyer, 2018;Schmidt & Majić, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…With the study at hand, we provide an overview of the subjective experiences induced by FLS. Apart from that, we were interested in phenomenologically comparing two conditions, using frequencies of 3 Hz and 10 Hz as previously applied by Schwartzman et al (2019). We presumed the latter to evoke stronger consciousness alterations and more FIVHs.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Altered states phenomena induced by visual flicker light stimulation

Bartossek¹,

Kemmerer²,

Schmidt³

2020

Preprint

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Flicker light stimulation (FLS) is a non-pharmacological method to induce short-term consciousness alterations, like hallucinatory perceptions of colors and geometric patterns. Recently, the phenomenologies of several techniques to induce altered states of consciousness (ASCs) were investigated in a structured manner. Such systematic quantification improves replicability, allows direct comparison between techniques and is the prerequisite to study their underlying neuronal mechanisms. In a within-subjects repeated measures design (N = 24), we assessed the subjective experiences during 3 Hz and 10 Hz FLS, by application of the Positive and Negative Affect Schedule (mood state), time perception ratings, the Altered State of Consciousness Rating Scale, and the Phenomenology of Consciousness Inventory. Furthermore, we tested for effects of personality traits (NEO Five-Factor Inventory-2 and Tellegen Absorption Scale) on subjective experiences. The data show that FLS-induced states were especially characterized by vivid visual imagery of simple and complex types, with stronger effects in the 10 Hz condition. In addition, we found high correlations between the intensity of the subjectively experienced alterations in consciousness state with participants’ personality trait of Absorption. Our data demonstrate that FLS can induce visual effects of comparable intensity as induced by psychedelic substances and thereby motivates investigation of potentially shared underlying neuronal mechanisms.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Altered states phenomena induced by visual flicker light stimulation

Bartossek¹,

Kemmerer²,

Schmidt³

2020

Preprint

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Visual hallucinations induced by Ganzflicker and Ganzfeld differ in frequency, complexity, and content

Shenyan,

Lisi,

Greenwood

et al. 2024

Sci Rep

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Visual hallucinations can be phenomenologically divided into those of a simple or complex nature. Both simple and complex hallucinations can occur in pathological and non-pathological states, and can also be induced experimentally by visual stimulation or deprivation—for example using a high-frequency, eyes-open flicker (Ganzflicker) and perceptual deprivation (Ganzfeld). Here we leverage the differences in visual stimulation that these two techniques involve to investigate the role of bottom-up and top-down processes in shifting the complexity of visual hallucinations, and to assess whether these techniques involve a shared underlying hallucinatory mechanism despite their differences. For each technique, we measured the frequency and complexity of the hallucinations produced, utilising button presses, retrospective drawing, interviews, and questionnaires. For both experimental techniques, simple hallucinations were more common than complex hallucinations. Crucially, we found that Ganzflicker was more effective than Ganzfeld at eliciting simple hallucinations, while complex hallucinations remained equivalent across the two conditions. As a result, the likelihood that an experienced hallucination was complex was higher during Ganzfeld. Despite these differences, we found a correlation between the frequency and total time spent hallucinating in Ganzflicker and Ganzfeld conditions, suggesting some shared mechanisms between the two methodologies. We attribute the tendency to experience frequent simple hallucinations in both conditions to a shared low-level core hallucinatory mechanism, such as excitability of visual cortex, potentially amplified in Ganzflicker compared to Ganzfeld due to heightened bottom-up input. The tendency to experience complex hallucinations, in contrast, may be related to top-down processes less affected by visual stimulation.

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Consciousness as a multidimensional phenomenon: implications for the assessment of disorders of consciousness

Walter

2021

Neuroscience of Consciousness

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Disorders of consciousness (DoCs) pose a significant clinical and ethical challenge because they allow for complex forms of conscious experience in patients where intentional behaviour and communication are highly limited or non-existent. There is a pressing need for brain-based assessments that can precisely and accurately characterize the conscious state of individual DoC patients. There has been an ongoing research effort to develop neural measures of consciousness. However, these measures are challenging to validate not only due to our lack of ground truth about consciousness in many DoC patients but also because there is an open ontological question about consciousness. There is a growing, well-supported view that consciousness is a multidimensional phenomenon that cannot be fully described in terms of the theoretical construct of hierarchical, easily ordered conscious levels. The multidimensional view of consciousness challenges the utility of levels-based neural measures in the context of DoC assessment. To examine how these measures may map onto consciousness as a multidimensional phenomenon, this article will investigate a range of studies where they have been applied in states other than DoC and where more is known about conscious experience. This comparative evidence suggests that measures of conscious level are more sensitive to some dimensions of consciousness than others and cannot be assumed to provide a straightforward hierarchical characterization of conscious states. Elevated levels of brain complexity, for example, are associated with conscious states characterized by a high degree of sensory richness and minimal attentional constraints, but are suboptimal for goal-directed behaviour and external responsiveness. Overall, this comparative analysis indicates that there are currently limitations to the use of these measures as tools to evaluate consciousness as a multidimensional phenomenon and that the relationship between these neural signatures and phenomenology requires closer scrutiny.

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Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness

Cited by 23 publications

References 62 publications

Altered states phenomena induced by visual flicker light stimulation

Altered states phenomena induced by visual flicker light stimulation

Visual hallucinations induced by Ganzflicker and Ganzfeld differ in frequency, complexity, and content

Consciousness as a multidimensional phenomenon: implications for the assessment of disorders of consciousness

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