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While the contingent negative variation (CNV) has been the subject of extensive research over the last fifty years, the maximum duration during which such cortical negativity can be maintained has, to the best of our knowledge, never been systematically explored. Participants were presented with the classic S1-S2 paradigm task, where a warning stimulus (S1) acts as a cue for the appearance of an imperative stimulus (S2). A fast motor response was required upon S2 arrival. Inter-stimulus intervals (ISIs) of 2.5, 5, 7.5 and 10 s duration were presented in blocked fashion. Data was analysed using both EEG referenced to linked mastoids and the current source density (CSD) technique, which maximizes the cortical origin of the measured voltage. Mean late CNV (lCNV) amplitude was found to be significantly higher for fast reaction time (RT) trials when CSD data was split according to the median into 'fast' and 'slow' RT halves. Post-hoc comparisons showed that this RT effect was particularly strong for the 10 s condition. This may be explained by the lack of an lCNV component and thus of cortical negativity prior to S2 in the 10 s condition. Our results suggest that intervals of a duration between 7.5 and 10 s represent the upper boundary during which the lCNV component can be elicited.

Greater vibrotactile sensitivity has been related to better erectile function in men, and vibrotactile and pressure tactile sensitivity have been related to better sexual function in women. Our previous study found that, for both sexes, greater recalled body awareness during last sexual relation correlated with greater recalled desire and arousal. Using the same sample of that study (68 women and 48 men, recruited in the Lisbon area, Portugal), we tested if greater recalled body awareness during last sexual relation correlates with tactile pressure sensitivity, as assessed by von Frey microfilaments. In simple and partial correlations controlling for social desirability and smoking before last sex, the hypothesis was confirmed for women, but not for men. Greater tactile sensitivity might enhance sexual arousal through greater awareness of the body during sex, and/or more frequent and pleasant body sensations during sex might lead to greater tactile sensitivity in nonsexual situations. Pressure sensitivity might be more closely linked to sexual arousal in women than in men.

The readiness potential is an ongoing negativity in the EEG preceding a self-initiated movement by approximately 1.5s. So far it has predominantly been interpreted as a preparatory signal with a causal link to the upcoming movement. Here a different hypothesis is suggested which we call the selective slow cortical potential sampling hypothesis. In this review of recent research results we argue that the initiation of a voluntary action is more likely during negative fluctuations of the slow cortical potential and that the sampling and averaging of many trials leads to the observed negativity. That is, empirical evidence indicates that the early readiness potential is not a neural correlate of preconscious motor preparation and thus a determinant of action. Our hypothesis thereafter challenges the classic interpretation of the Libet experiment which is often taken as proof that there is no free will. We furthermore suggest that slow cortical potentials are related to an urge to act but are not a neural indicator of the decision process of action initiation.

There is lack of research on effects of red wine on consciousness when drank in wine bars designed to enhance the pleasurableness of the wine drinking experience. Effects of a moderate dose of red wine (≈ 40.98 g of ethanol) on consciousness were examined in a naturalistic study taking place in a wine bar located in one of the most touristic areas of Lisbon, Portugal. One hundred two participants drank in one of three conditions: alone, in dyad, or in groups up to six people. Red wine increased pleasure and arousal, decreased the awareness of time, slowed the subjective passage of time, increased the attentional focus on the present moment, decreased body awareness, slowed thought speed, turned imagination more vivid, and made the environment become more fascinating. Red wine increased insightfulness and originality of thoughts, increased sensations of oneness with the environment, spiritual feelings, all-encompassing love, and profound peace. All changes in consciousness occurred regardless of volunteers drinking alone, in dyad or in group. Men and women did not report different changes in consciousness. Older age correlated with greater increases in pleasure. Younger age correlated with greater increases in fascination with the environment of the wine bar. Drinking wine in a contemporaneous Western environment designed to enhance the pleasurableness of the wine drinking experience may trigger changes in consciousness commonly associated with mystical-type states.

Floatation-REST (Reduced Environmental Stimulation Therapy) minimizes stimulation of the nervous system by immersing subjects in an environment without sound or light while they effortlessly float in thermoneutral water supersaturated with Epsom salt. Here we investigated the relationship between altered states of consciousness (ASC) and its association with the affective changes induced by Floatation-REST. Using a within-subject crossover design, 50 healthy subjects were randomized to 60 min of Floatation-REST or 60 min of Bed-REST (an active control condition that entailed lying supine on a warm waterbed in a dark and quiet room). Following Floatation-REST, subjects felt significantly more relaxed, less anxious, and less tired than after Bed-REST. Floatation-REST also induced significantly more pronounced ASC characterized by the dissolution of body boundaries and the distortion of subjective time. The loss of body boundaries mediated the loss of anxiety, revealing a novel mechanism by which Floatation-REST exerts its anxiolytic effect.

This study examined the effects of meditative states in experienced meditators on present-moment awareness, subjective time, and self-awareness while assessing meditation-induced changes in heart-rate variability and breathing rate. A sample of 22 experienced meditators who practiced meditation techniques stressing awareness of the present moment (average 20 years of practice) filled out subjective scales pertaining to sense of time and the bodily self and accomplished a metronome task as an operationalization of present-moment awareness before and after a 20 min meditation session (experimental condition) and a 20 min reading session (control condition) according to a within-subject design. A mixed pattern of increased sympathetic and parasympathetic activity was found during meditation regarding heart-rate measures. Breathing intervals were prolonged during meditation. Participants perceived their body boundaries as less salient during meditation than while reading the story; they also felt time passed more quickly and they paid less attention to time during meditation. No significant differences between conditions became apparent for the metronome task. This is probably the first quantitative study to show how the experience of time during a meditation session is altered together with the sense of the bodily self.

Abnormal auditory temporal processing might be an underlying deficit in language disabilities. The auditory temporal-order threshold, one measure for temporal processing abilities, is defined as the shortest time interval between two acoustic events necessary for a person to be able to identify the correct temporal order. In our study, we examined the reliability of the auditory temporal-order threshold during a one-week period and over a time interval of four months in normally developing children aged 5 to 11 years. The results of our method show that children younger than 7 years have difficulties performing the task successfully. The reliability of the assessment of the temporal-order threshold during a period of one week is only moderate, and its stability over a time interval of four months is low. The results show that auditory-order thresholds in children have to be treated with caution. A high temporal-order threshold does not necessarily predict disabilities in temporal processing.

The role of the heart in the experience of time has been long theorized but empirical evidence is scarce. Here, we examined the interaction between fine-grained cardiac dynamics and the momentary experience of subsecond intervals. Participants performed a temporal bisection task for brief tones (80-188 ms) synchronized with the heart. We developed a cardiac Drift-Diffusion Model (cDDM) that embedded contemporaneous heart rate dynamics into the temporal decision model. Results revealed the existence of temporal wrinkles-dilation or contraction of short intervals-in synchrony with cardiac dynamics. A lower prestimulus heart rate was associated with an initial bias in encoding the millisecond-level stimulus duration as longer, consistent with facilitation of sensory intake. Concurrently, a higher prestimulus heart rate aided more consistent and faster temporal judgments through more efficient evidence accumulation. Additionally, a higher speed of poststimulus cardiac deceleration, a bodily marker of attention, was associated with a greater accumulation of sensory temporal evidence in the cDDM. These findings suggest a unique role of cardiac dynamics in the momentary experience of time. Our cDDM framework opens a new methodological avenue for investigating the role of the heart in time perception and perceptual judgment.

During the observation of an ambiguous figure our perception alternates between mutually exclusive interpretations, although the stimulus itself remains unchanged. The rate of these endogenous reversals has been discussed as reflecting basic aspects of endogenous brain dynamics. Recent evidence indicates that extensive meditation practice evokes long-term functional and anatomic changes in the brain, also affecting the endogenous brain dynamics. As one of several consequences the rate of perceptual reversals during ambiguous figure perception decreases. In the present study we compared EEG-correlates of endogenous reversals of ambiguous figures between meditators and non-meditating controls in order to better understand timing and brain locations of this altered endogenous brain dynamics. A well-established EEG paradigm was used to measure the neural processes underlying endogenous perceptual reversals of ambiguous figures with high temporal precision. We compared reversal-related ERPs between experienced meditators and non-meditating controls. For both groups we found highly similar chains of reversal-related ERPs, starting early in visual areas, therewith replicating previous findings from the literature. Meditators, however, showed an additional frontal ERP signature already 160 ms after stimulus onset (Frontal Negativity). We interpret the additional, meditation-specific ERP results as evidence that extensive meditation practice provides control of frontal brain areas over early sensory processing steps. This may allow meditators to overcome phylogenetically evolved perceptual and attentional processing automatisms.

(1) Background: Mind-body interventions (MBI), such as meditation or other relaxation techniques, have become the focus of attention in the clinical and health sciences. Differences in the effects of induction techniques are being increasingly investigated. (2) Methods: Here, we compared changes in the individual experience of time, space, and self in 44 students in an integrative health-promotion program. They participated in a study employing mindfulness meditation and a relaxation intervention with one week between sessions, thus employing a within-subjects design. (3) Results: No significant differences were detected when subjective reports were compared directly after each intervention. However, we found significant sequence effects between t1 and t2, independent of the meditation type. The sense of self diminished, the present orientation increased, and the past and future orientations decreased in both interventions. (4) Conclusions: We propose using scales to assess subjective time, self, and space as basic constituents of experience to measure the specificity of intervention methods, as well as longitudinal changes.

OBJECTIVES: The study aimed to clarify whether cognitive and psychomotor performance, which are important for occupational and traffic safety, are impaired by working permanent night shifts (NSs) compared with early-late two shifts (TSs) and whether age and chronobiological type influences the relationship between shift and performance. METHODS: The study included 44 male automobile workers, 20 working TSs and 24 working NSs. Chronobiological type was determined by questionnaire (D-MEQ). Each subject was tested at the beginning and end of the shift for alertness [by a visual analogue scale (VAS)]; feeling of well-being (Basler); concentration and accuracy (d2); reaction speed, orientation and reaction to stress (Vienna System). RESULTS: TS workers were more frequently morning types whereas the NS workers were more frequently evening types. In the performance tests, the TS and NS workers did not differ at shift start or shift end. Over the course of the shift, concentration and accuracy improved in both groups, as did reaction to stress. Chronobiological type alone or in combination with shift type had no effect on performance. CONCLUSIONS: The results of this study indicate that-if chosen voluntarily-working NSs has no immediate negative effects on cognitive and psychomotor performance when compared with working TSs. There was no indication of an increased risk of accidents after working NSs. The unequal distribution of the circadian types in the shift groups may indicate selection.

An object moving towards an observer is subjectively perceived as longer in duration than the same object that is static or moving away. This "time dilation effect" has been shown for a number of stimuli that differ from standard events along different feature dimensions (e.g. color, size, and dynamics). We performed an event-related functional magnetic resonance imaging (fMRI) study, while subjects viewed a stream of five visual events, all of which were static and of identical duration except the fourth one, which was a deviant target consisting of either a looming or a receding disc. The duration of the target was systematically varied and participants judged whether the target was shorter or longer than all other events. A time dilation effect was observed only for looming targets. Relative to the static standards, the looming as well as the receding targets induced increased activation of the anterior insula and anterior cingulate cortices (the "core control network"). The decisive contrast between looming and receding targets representing the time dilation effect showed strong asymmetric activation and, specifically, activation of cortical midline structures (the "default network"). These results provide the first evidence that the illusion of temporal dilation is due to activation of areas that are important for cognitive control and subjective awareness. The involvement of midline structures in the temporal dilation illusion is interpreted as evidence that time perception is related to self-referential processing.

BACKGROUND: Distant intention research refers to experiments in which a distant interaction between two persons is assessed that precludes conventional communication. In these experiments the intention of one person is varied systematically while the effect of this variation is assessed in the remote other person. AIMS: Our study aimed at improving effect sizes by participant selection based on a screening test and by including experienced meditators. METHOD: 66 participants with meditation experience participated in a forced-choice psi-test as a screening test. Participants with similar performance were invited as pairs for a distant intention experiment. The task of the helpee was to focus attention on a candle and to indicate lapses in attention by pressing a button. In a within-subject design the task of the remote helper was either to assist the helpee in this effort or to engage in a distraction task. Electrodermal activity (EDA) and button presses from the helpee served as dependent variables. RESULTS AND CONCLUSION: Participants' performance in the psi-screening test did not exceed chance expectations. In the distant intention experiment with 30 sessions no distant intention effect could be found in the prespecified analyses. The results in the psi-screening test were not correlated with performance in the main experiment. However, we found a large negative correlation between self-reported exceptional experiences of the helper and two EDA variables, namely skin conductance level and number of non-specific skin conductance responses. This correlation, if replicated, can hardly be explained without the assumption of a distant interaction.

It has been repeatedly shown that specific brain activity related to planning movement develops before the conscious intention to act. This empirical finding strongly challenges the notion of free will. Here, we demonstrate that in the Libet experiment, spontaneous fluctuations of the slow electro-cortical potentials (SCPs) account for a significant fraction of the readiness potential (RP). The individual potential shifts preceding self-initiated movements were classified as showing a negative or positive shift. The negative and positive potential shifts were analyzed in a self-initiated movement condition and in a no-movement condition. Comparing the potential shifts between both conditions, we observed no differences in the early part of the potential. This reveals that the apparently negative RP emerges through an unequal ratio of negative and positive potential shifts. These results suggest that ongoing negative shifts of the SCPs facilitate self-initiated movement but are not related to processes underlying preparation or decision to act.

The belief in free will has been frequently challenged since Benjamin Libet published his famous experiment in 1983. Although Libet's experiment is highly dependent upon subjective reports, no study has been conducted that focused on a first-person or introspective perspective of the task. We took a neurophenomenological approach in an N=1 study providing reliable and valid measures of the first-person perspective in conjunction with brain dynamics. We found that a larger readiness potential (RP) is attributable to more frequent occurrences of self-initiated movements during negative deflections of the slow cortical potentials (SCP). These negative deflections occur in parallel with an inner impulse reported by an expert meditator which may in turn lead to a voluntary act. We demonstrate in this proof-of-principle approach that the first-person perspective obtained by an expert meditator in conjunction with neural signal analysis can contribute to our understanding of the neural underpinnings of voluntary acts.

INTRODUCTION: We tested and validated the German version of a new instrument for measuring "wakefulness," defined as "an expansive, higher-functioning, and stable state of being in which a person's vision of and relationship to the world are transformed, along with their subjective experience, their sense of identity and their conceptual outlook" (Taylor, 2017, p. 22). METHODS: In order to test the construct validity of the new instrument (Inventory of Secular/Spiritual Wakefulness; WAKE-16), we performed a parametric comparison between a group of expert meditators (n=36) with a history of predominantly meditating in silence and demographically matched non-meditators (n=36) for the WAKE-16 and two conceptually related questionnaires of mindfulness and emotion regulation. RESULTS: Significantly higher scores for the meditators on the WAKE-16 indicate construct validity of the new instrument. Meditators scored higher on the two mindfulness subscales "presence" and "acceptance," as well as on the SEE subscales of emotion regulation and body-related symbolization of emotions. Within the group of meditators, there were significant correlations between wakefulness and mindfulness, accepting one's own emotions, and experiencing overwhelming emotions. The only significant correlation in non-meditators was found between wakefulness and accepting one's own emotions. DISCUSSION: The new instrument shows construct validity by discriminating between the two groups. Correlations between wakefulness and related psychological constructs indicate convergent validity. Future studies could attempt to increase discriminatory accuracy of the definition of wakefulness, as well as finding objective methods of measuring.

In recent years, there has been a renewed interest in the conceptual and empirical study of altered states of consciousness (ASCs) induced pharmacologically or otherwise, driven by their potential clinical applications. To draw attention to the rich history of research in this domain, we review prominent classification schemes that have been proposed to introduce systematicity in the scientific study of ASCs. The reviewed ASC classification schemes fall into three groups according to the criteria they use for categorization: (1) based on the nature, variety, and intensity of subjective experiences (state-based), including conceptual descriptions and psychometric assessments, (2) based on the technique of induction (method-based), and (3) descriptions of neurophysiological mechanisms of ASCs (neuro/physio-based). By comparing and extending existing classification schemes, we can enhance efforts to identify neural correlates of consciousness, particularly when examining mechanisms of ASC induction and the resulting subjective experience. Furthermore, an overview of what defining ASC characteristics different authors have proposed can inform future research in the conceptualization and quantification of ASC subjective effects, including the identification of those that might be relevant in clinical research. This review concludes by clustering the concepts from the state-based schemes, which are suggested for classifying ASC experiences. The resulting clusters can inspire future approaches to formulate and quantify the core phenomenology of ASC experiences to assist in basic and clinical research.

In recent years, there has been a renewed interest in the conceptual and empirical study of altered states of consciousness (ASCs), induced pharmacologically or otherwise, driven by their potential clinical applications. To draw attention to the rich history of research in this domain, we review prominent classification schemes that have been proposed to introduce systematicity into the scientific study of ASCs. The reviewed ASC classification schemes fall into three groups according to the criteria they use for categorization: (1) based on the nature, variety, and intensity of subjective experiences (state-based), including conceptual descriptions and psychometric assessments, (2) based on the technique of induction (method-based), and (3) descriptions of neurophysiological mechanisms of ASCs (neuro/physio-based). By comparing and extending existing classification schemes, we can enhance efforts to identify neural correlates of consciousness, particularly when examining mechanisms of ASC induction and the resulting subjective experiences. Furthermore, an overview of what defining ASC characteristics different authors have proposed can inform future research in the conceptualization and quantification of ASC subjective effects, including the identification of those that might be relevant in clinical research. This review concludes by clustering the concepts from the state-based schemes, which are suggested for classifying ASC experiences. The resulting clusters can inspire future approaches to formulate and quantify the core phenomenology of ASC experiences to assist in basic and clinical research.

Recent research suggests that bodily signals and interoception are strongly related to our sense of time. Mindfulness meditators train to be aware of their body states and therefore could be more accurate at interval timing. In this study, n = 22 experienced mindfulness meditators and n = 22 matched controls performed both, an acoustic and a visual duration reproduction task of 8, 14, and 20 s intervals, while heart rate and skin conductance were continuously assessed. In addition, participants accomplished a heart beat perception task and two selective attention tasks. Results revealed no differences between meditators and controls with respect to performance in duration reproduction or attentional capacities. Additionally no group difference in heart beat perception scores was found. Across all subjects, correlational analyses revealed several associations between performance in the duration reproduction tasks and psychophysiological changes, the latter being also related to heart beat perception scores. Furthermore, former findings of linearly increasing cardiac periods and decreasing skin conductance levels during the auditory duration estimation task (Meissner and Wittmann, 2011) could be replicated, and these changes could also be observed during a visual duration reproduction task. In contrast to our earlier findings, the heart beat perception test was not related with timing performance. Overall, although experienced meditators did not differ from matched controls with respect to duration reproduction and interoceptive awareness, this study adds significantly to the emerging view that time perception is related to autonomic regulation and awareness of body states.

The concept of the minimal self refers to the consciousness of oneself as an immediate subject of experience. According to recent studies, disturbances of the minimal self may be a core feature of schizophrenia. They are emphasized in classical psychiatry literature and in phenomenological work. Impaired minimal self-experience may be defined as a distortion of one's first-person experiential perspective as, for example, an "altered presence" during which the sense of the experienced self ("mineness") is subtly affected, or "altered sense of demarcation," i.e., a difficulty discriminating the self from the non-self. Little is known, however, about the cognitive basis of these disturbances. In fact, recent work indicates that disorders of the self are not correlated with cognitive impairments commonly found in schizophrenia such as working-memory and attention disorders. In addition, a major difficulty with exploring the minimal self experimentally lies in its definition as being non-self-reflexive, and distinct from the verbalized, explicit awareness of an "I." In this paper, we shall discuss the possibility that disturbances of the minimal self observed in patients with schizophrenia are related to alterations in time processing. We shall review the literature on schizophrenia and time processing that lends support to this possibility. In particular we shall discuss the involvement of temporal integration windows on different time scales (implicit time processing) as well as duration perception disturbances (explicit time processing) in disorders of the minimal self. We argue that a better understanding of the relationship between time and the minimal self as well of issues of embodiment require research that looks more specifically at implicit time processing. Some methodological issues will be discussed.