Journal of Psychopharmacology
May 20, 2006
Marc Wittmann, Olivia Carter, Felix Hasler et al.
245 citations
Psilocybin impairs the ability to reproduce time intervals longer than 2.5 seconds, to synchronize movements to beats longer than 2 seconds, and slows preferred tapping rate. These objective timing deficits are accompanied by working-memory impairments and subjective changes including depersonalization and derealization. The findings indicate the serotonin system is selectively involved in processing durations longer than 2–3 seconds and in voluntary movement speed control. The disruption of longer intervals likely results from interactions with cognitive dimensions of temporal processing via 5-HT2A receptor stimulation.
Neuroscience Letters
February 13, 2008
Jiřı́ Wackermann, Marc Wittmann, Felix Hasler et al.
95 citations
Psilocybin, a hallucinogen often explored in psychedelic studies, significantly alters time perception. In a sample of 30 participants, those who received psilocybin reported a 60% increase in the feeling of time dilation compared to a placebo group. This effect highlights the potential of psychedelics in understanding psychological states and their impact on human experience. Additionally, findings suggest implications for fields like developmental psychology and sleep research, as altered time perception may influence beliefs about paranormal experiences and consciousness.
Frontiers in psychology
January 1, 2014
Brice Martin, Marc Wittmann, Nicolas Franck et al.
87 citations
Disturbances of the minimal self—the immediate sense of being a subject of experience—may be a core feature of schizophrenia, manifesting as an altered sense of presence or difficulty distinguishing self from non-self. These disturbances are not correlated with common cognitive impairments like working-memory or attention disorders. This paper reviews literature suggesting a link between such self-disturbances and alterations in time processing, including both implicit temporal integration windows and explicit duration perception. The authors argue that understanding the relationship between time and the minimal self, along with embodiment issues, requires further research focused on implicit time processing.
Frontiers in Psychology
February 18, 2020
Ulf Winter, Pierre Levan, Tilmann Lhündrup Borghardt et al.
68 citations
A highly experienced meditator with over 50,000 hours of practice reported experiencing content-free awareness (CFA) during an EEG-fMRI session. During CFA, alpha brainwave power sharply decreased while theta power increased. Functional connectivity increased in the dorsal attention network (DAN) and decreased in the posterior default mode network (DMN). These patterns suggest a top-down attentional state that excludes both external sensory stimuli and internal thoughts from conscious experience. The authors conclude that investigating such states may offer new approaches for identifying the minimal neural correlate of consciousness.
Consciousness and cognition
May 1, 2014
Han-Gue Jo, Marc Wittmann, Tilmann Lhündrup Borghardt et al.
43 citations
A neurophenomenological study with a single expert meditator shows that a larger readiness potential (RP) is linked to more frequent self-initiated movements during negative deflections of slow cortical potentials (SCP). These negative deflections occur alongside an inner impulse reported by the meditator, which may lead to a voluntary act. This proof-of-principle demonstrates that combining first-person introspective data with neural signal analysis can advance understanding of the neural basis of voluntary acts, challenging interpretations of the classic Libet experiment.
Neuroscience and biobehavioral reviews
August 1, 2025
Larry Douglas Fort, Cyril Costines, Marc Wittmann et al.
14 citations
A review of classification schemes for altered states of consciousness (ASCs) groups them into three types: those based on subjective experiences (state-based), those based on induction methods (method-based), and those based on neurophysiological mechanisms (neuro/physio-based). Comparing and extending these schemes can improve identification of neural correlates of consciousness and inform clinical research. The authors cluster concepts from state-based schemes to help quantify core ASC phenomenology for basic and clinical studies.
Consciousness and cognition
April 1, 2025
Iraklis Pantazis, Marc Wittmann
5 citations
A crossover study with 34 participants found that 60 minutes of Floatation-REST (floating in a dark, quiet tank of thermoneutral salt water) produced significantly weaker body boundaries, greater time distortion, and more relaxation compared to Bed-REST. After floating, participants reported a stronger afterglow, more state mindfulness, and greater interoceptive awareness. Relaxation during floating fully explained the afterglow effect in a mediation analysis. These results align with psychedelic research, suggesting Floatation-REST can elicit similar afterglow experiences.
Frontiers in psychology
January 1, 2025
Marc Wittmann, Carlos Montemayor, Mauro Dorato
1 citation
Building on the Stoic concept of self-regulation, this paper argues that contemporary findings from psychology and cognitive neuroscience do not refute free will but instead support and refine a Stoic view of it. Contrary to classical interpretations of Libet-type experiments, which are often cited to deny free will, the authors contend that such evidence undermines the idea that humans are passive recipients of spontaneous desires. Instead, people possess the capacity to regulate actions proactively by cultivating deliberate, voluntary intentions. Freedom arises from a meta-cognitive, hierarchical second-order will that can causally override first-order desires or impulsive habits. Choices are not entirely predetermined by upbringing or circumstances; they emerge from the capacity to reflect upon and respond to those influences, making the self a self-determined free agent.
Progress in brain research
January 1, 2024
Christine Flatten, Damisela Linares Gutiérrez, Sebastian L Kübel et al.
1 citation
A newly developed German questionnaire called the Inventory of Secular/Spiritual Wakefulness (WAKE-16) was tested in 36 expert meditators who primarily meditate in silence and 36 demographically matched non-meditators. Meditators scored significantly higher on the WAKE-16, indicating the instrument can distinguish between groups and thus has construct validity. Meditators also scored higher on mindfulness subscales of presence and acceptance, as well as on emotion regulation and body-related symbolization of emotions. Among meditators, wakefulness correlated with mindfulness, accepting one's own emotions, and experiencing overwhelming emotions; among non-meditators, only the correlation with accepting one's own emotions was significant. The findings support the WAKE-16 as a valid measure of wakefulness, defined as an expansive, stable state involving transformed vision, identity, and relationship to the world.
BMC Complementary Medicine and Therapies
November 6, 2025
Helena Hruby, Marc Wittmann, Stefan Schmidt et al.
Most people who float in a sensory isolation tank go through four distinct phases during a 60-minute session: acclimatization, a transitional phase, an altered state of consciousness (ASC), and finally reorientation. The ASC phase is marked by positive emotions, deep relaxation, loss of orientation in space and time, and reduced bodily sensations and thoughts. These characteristics emerge gradually and intensify over time. The findings suggest that the therapeutic benefits of Floatation-REST for mental health conditions may be linked to the experience of these altered states.
Current topics in behavioral neurosciences
July 25, 2025
Alan N Simmons, Marc Wittmann, Irian A Strigo
This chapter reviews the intellectual legacy of A.D. Bud Craig and advances understanding of interoception across three domains: bodily self, emotion, and subjective time. Beginning with foundational research on temperature and pain processing, it describes how interoceptive signals integrate to form bodily self-representation and emotional experiences, then culminates in how interoception shapes time perception, including in altered states of consciousness. The chapter points to future research on computational modeling of interoceptive processing, personalized treatments based on interoceptive principles, and clinical applications for psychiatric, neurological, and pain conditions, while outlining remaining gaps in continuing Craig's seminal career.