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The Necker-Zeno model of bistable perception provides a formal relation between the average duration of meta-stable percepts (dwell times T) of ambiguous figures and two other basic time scales (t(0), ΔT) underlying cognitive processing. The model predicts that dwell times T covary with t(0), ΔT or both. We tested this prediction by exploiting that observers, in particular experienced meditators, can volitionally control dwell times T. Meditators and non-meditators observed bistable Necker cubes either passively or tried to hold their current percept. The latencies of a centro-parietal event-related potential (CPP) were recorded as a physiological correlate of t(0). Dwell times T and the CPP latencies, correlated with t(0), differed between conditions and observer groups, while ΔT remained constant in the range predicted by the model. The covariation of CPP latencies and dwell times, as well as their quadratic functional dependence extends previous psychophysical confirmation of the Necker-Zeno model to psychophysiological measures.

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 misinformation effect refers to memory impairment that arises after exposure to misleading information (Loftus, 2005, p. 361). The present study focuses on the peripheral psychophysiology of false memories induced in a misleading information paradigm. On the basis of Sokolov's orienting reflex and studies concerning the Concealed Information Test (CIT, Lykken, 1959), the main hypothesis assumes differences between true and false memories in terms of the accompanying autonomic measures. It also is assumed that a cued recall of original information preceding the recollection phase reduces misinformation effects. Seventy-five participants watched a video that included nine randomized details. After a ten-minute retention phase, the subjects read a narrative text. Six out of the nine details were replaced by misleading details. Following this, the participants completed a cued recall task for three of the original items. In a subsequent CIT with truthful answering electrodermal responses, phasic heart rate, respiration, and response behavior were measured. Finally, the level of confidence and source monitoring were assessed. The misinformation effect was replicated with newly developed materials in three recollection tasks. Cued recall had no influence on the misinformation effect. Autonomic measures did not differ between true and false memories in the CIT. Electrodermal responses reflected the subjective importance the participants attributed to details in the source monitoring task. Therefore, electrodermal responses are interpreted as a correlate of subjective remembering in a misinformation paradigm.

The worldwide fascination of da Vinci's Mona Lisa has been dedicated to the emotional ambiguity of her face expression. In the present study we manipulated Mona Lisa's mouth curvature as one potential source of ambiguity and studied how a range of happier and sadder face variants influences perception. In two experimental conditions we presented different stimulus ranges with different step sizes between stimuli along the happy-sad axis of emotional face expressions. Stimuli were presented in random order and participants indicated the perceived emotional face expression (first task) and the confidence of their response (second task). The probability of responding 'happy' to the original Mona Lisa was close to 100%. Furthermore, in both conditions the perceived happiness of Mona Lisa variants described sigmoidal functions of the mouth curvature. Participants' confidence was weakest around the sigmoidal inflection points. Remarkably, the sigmoidal functions, as well as confidence values and reaction times, differed significantly between experimental conditions. Finally, participants responded generally faster to happy than to sad faces. Overall, the original Mona Lisa seems to be less ambiguous than expected. However, perception of and reaction to the emotional face content is relative and strongly depends on the used stimulus range.

BACKGROUND: During observation of the Necker cube perception becomes unstable and alternates repeatedly between a from-above-perspective ("fap") and a from-below-perspective ("fbp") interpretation. Both interpretations are physically equally plausible, however, observers usually show an a priori top-down bias in favor of the fap interpretation. Patients with Autism spectrum disorder are known to show an altered pattern of perception with a focus on sensory details. In the present study we tested whether this altered perceptual processing affects their reversal dynamics and reduces the perceptual bias during Necker cube observation. METHODS: 19 participants with Asperger syndrome and 16 healthy controls observed a Necker cube stimulus continuously for 5 minutes and indicated perceptual reversals by key press. We compared reversal rates (number of reversals per minute) and the distributions of dwell times for the two interpretations between observer groups. RESULTS: Asperger participants showed less perceptual reversal than controls. Six Asperger participants did not perceive any reversal at all, whereas all observers from the control group perceived at least five reversals within the five minutes observation time. Further, control participants showed the typical perceptual bias with significant longer median dwell times for the fap compared to the fbp interpretation. No such perceptual bias was found in the Asperger group. DISCUSSION: The perceptual system weights the incomplete and ambiguous sensory input with memorized concepts in order to construct stable and reliable percepts. In the case of the Necker cube stimulus, two perceptual interpretations are equally compatible with the sensory information and internal fluctuations may cause perceptual alternations between them-with a slightly larger probability value for the fap interpretation (perceptual bias). Smaller reversal rates in Asperger observers may result from the dominance of bottom-up sensory input over endogenous top-down factors. The latter may also explain the absence of a fap bias.

Environmental information available to our senses is incomplete and to varying degrees ambiguous. It has to be disambiguated in order to construct stable and reliable percepts. Ambiguous figures are artificial examples where perception is maximally unstable and alternates between possible interpretations. Tiny low-level changes can disambiguate an ambiguous figure and thus stabilize percepts. The present study compares ERPs evoked by ambiguous stimuli and disambiguated stimulus variants across three visual categories: geometry (Necker cube), motion (stroboscopic alternative motion stimulus, SAM) and semantics (Boring's old/young woman). We found that (a) disambiguated stimulus variants cause stable percepts and evoke two huge positive ERP excursions (Cohen's effect sizes 1-2), (b) the amplitudes of these ERP effects are inversely related to the degree of stimulus ambiguity, and (c) this pattern of results is consistent across all three tested visual categories. This generality across visual categories points to mechanisms at a very abstract (cognitive) level of processing. We discuss our results in the context of a high-level Bayesian inference unit that evaluates the reliability of perceptual processing results, given a priori incomplete, ambiguous sensory information. The ERP components may reflect the outcome of this reliability estimation.

Altered states of consciousness lead to profound changes in the sense of self, time and space. We assessed how these changes were related to sexual responsiveness during sex. 116 subjects reported (a) intensity of awareness concerning body, space and time, and (b) satisfaction, desire, arousal, and orgasm occurrence. We differentiated vaginal intercourse orgasm from noncoital orgasm. Female vaginal intercourse orgasm was further differentiated as with or without concurrent clitoral masturbation. Overall, sexual responsiveness was related to greater body awareness and lesser time and space awareness. Satisfaction, desire, and arousal were especially associated with less time awareness in women. Female orgasms during vaginal intercourse were related to greater body awareness and lesser time awareness, but noncoital orgasms were unrelated. Our findings provide empirical support for the hypotheses that altered states of consciousness with attentional absorption are strongly related to sexual responsiveness in women, and to a lesser extent in men.

Research findings link rolandic beta-band activity to voluntary movements, but a linkage with the decision time to move remains unknown. We found that beta-band (16-28Hz) activity shortly before the movement onset is relevant for the decision time to move: the more pronounced the decrease in beta-band synchronization, the earlier the subjective experience of the decision to move. The linkage was relevant regarding 'decision', but not regarding 'intention' timing that has been often applied in the study of free will. Our findings suggest that oscillatory neural activity in the beta-band is an important neural signature pertaining to the subjective experience of making a decision to move.

Patients with schizophrenia have often been described as insensitive to nociceptive signals, but objective evidence is sparse. We address this question by combining subjective behavioral and objective neurochemical and neurophysiological measures. The present study involved 21 stabilized and mildly symptomatic patients with schizophrenia and 21 control subjects. We applied electrical stimulations below the pain threshold and assessed sensations of pain and unpleasantness with rating scales, and Somatosensory Evoked Potentials (SEPs/EEG). We also measured attention, two neurochemical stress indices (ACTH/cortisol), and subjective VEPs/EEG responses to visual emotional stimuli. Our results revealed that, subjectively, patients' evaluations do not differ from controls. However, the amplitude of EEG evoked potentials was greater in patients than controls as early as 50 ms after electrical stimulations and beyond one second after visual processing of emotional pictures. Such responses could not be linked to the stress induced by the stimulations, since stress hormone levels were stable. Nor was there a difference between patients and controls in respect of attention performance and tactile sensitivity. Taken together, all indices measured in patients in our study were either heightened or equivalent relative to healthy volunteers.

BACKGROUND: In von Schiller's Stroboscopic Alternative Motion (SAM) stimulus two visually presented diagonal dot pairs, located on the corners of an imaginary rectangle, alternate with each other and induce either horizontal, vertical or, rarely, rotational motion percepts. SAM motion perception can be described by a psychometric function of the dot aspect ratio ("AR", i.e. the relation between vertical and horizontal dot distances). Further, with equal horizontal and vertical dot distances (AR = 1) perception is biased towards vertical motion. In a series of five experiments, we presented tactile SAM versions and studied the role of AR and of different reference frames for the perception of tactile apparent motion. METHODS: We presented tactile SAM stimuli and varied the ARs, while participants reported the perceived motion directions. Pairs of vibration stimulators were attached to the participants' forearms and stimulator distances were varied within and between forearms. We compared straight and rotated forearm conditions with each other in order to disentangle the roles of exogenous and endogenous reference frames. RESULTS: Increasing the tactile SAM's AR biased perception towards vertical motion, but the effect was weak compared to the visual modality. We found no horizontal disambiguation, even for very small tactile ARs. A forearm rotation by 90° kept the vertical bias, even though it was now coupled with small ARs. A 45° rotation condition with crossed forearms, however, evoked a strong horizontal motion bias. DISCUSSION: Existing approaches to explain the visual SAM bias fail to explain the current tactile results. Particularly puzzling is the strong horizontal bias in the crossed-forearm conditions. In the case of tactile apparent motion, there seem to be no fixed priority rule for perceptual disambiguation. Rather the weighting of available evidence seems to depend on the degree of stimulus ambiguity, the current situation and on the perceptual strategy of the individual observer.

Hardly any empirical work exists concerning the relationship between the intra-individually stable time perspective relating to the past, present, and future and the subjective speed of time passing in everyday life. Moreover, studies consistently show that the subjective passage of time over the period of the last ten years speeds up as we get older. Modulating variables influencing this phenomenon are still unknown. To investigate these two unresolved issues, we conducted an online survey with n = 423 participants ranging in age between 17 and 81 assessing trait time perspective of the past, present, and future, and relating these subscales with a battery of measures pertaining to the subjective passage of time. Moreover, the subjective passage of time as an age-dependent variable was probed in relationship to emotion awareness, appraisal and regulation. Results show how present hedonism is linked with having fewer routines in life and a faster passage of the last week; the past negative perspective is related to time pressure, time expansion and more routine; a pronounced future perspective is related to a general faster passage of time. Importantly, increased emotion regulation and a balanced time perspective are related to a slower passage of the last ten years. These novel findings are discussed within models of time perception and the time perspective.

In the general concept of self-disturbances in schizophrenia and schizophrenia spectrum disorders, somatopsychic depersonalization (SPD) occupies a special place as it constitutes a syndrome that comprises feelings of detachment from one's own body and mental processes. However, apart from clinical descriptions, to date the pathophysiology of SPD is not fully understood due to the rareness of the syndrome and a lack of experimental studies. In a case study of one patient with schizotypal disorder, we applied a multimodal approach to understanding the SPD phenomena. The patient's clinical profile was identified as disruption of implicit bodily function, accompanied by depressive symptoms. On a neuropsychological level, the patient exhibited impairment in executive functioning, intact tactile perception and kinesthetic praxis. Behavioral tests revealed an altered sense of time but unimpaired self-agency. Furthermore, the patient exhibited a lack of empathy and he had autistic traits, although with a sufficient ability to verbalize his feelings. On the neurobiological level using an active and passive touch paradigm during functional magnetic resonance imaging (fMRI), we found a hyperconnectivity of the default-mode network and salience network and a hypoconnectivity of the central executive brain networks in the performance of the touch task as well as intact perceptual touch processing emerging from the direct comparisons of the touch conditions. Our data provide evidence for the important role of altered large-brain network functioning in SPD that corresponds to the specific behavioral and neurocognitive phenomena.

BACKGROUND: Nearly half of individuals with substance use disorders relapse in the year after treatment. A diagnostic tool to help clinicians make decisions regarding treatment does not exist for psychiatric conditions. Identifying individuals with high risk for relapse to substance use following abstinence has profound clinical consequences. This study aimed to develop neuroimaging as a robust tool to predict relapse. METHODS: 68 methamphetamine-dependent adults (15 female) were recruited from 28-day inpatient treatment. During treatment, participants completed a functional MRI scan that examined brain activation during reward processing. Patients were followed 1 year later to assess abstinence. We examined brain activation during reward processing between relapsing and abstaining individuals and employed three random forest prediction models (clinical and personality measures, neuroimaging measures, a combined model) to generate predictions for each participant regarding their relapse likelihood. RESULTS: 18 individuals relapsed. There were significant group by reward-size interactions for neural activation in the left insula and right striatum for rewards. Abstaining individuals showed increased activation for large, risky relative to small, safe rewards, whereas relapsing individuals failed to show differential activation between reward types. All three random forest models yielded good test characteristics such that a positive test for relapse yielded a likelihood ratio 2.63, whereas a negative test had a likelihood ratio of 0.48. CONCLUSIONS: These findings suggest that neuroimaging can be developed in combination with other measures as an instrument to predict relapse, advancing tools providers can use to make decisions about individualized treatment of substance use disorders.

Intuitively, being aware of one's inner processes to move should be crucial for the control of voluntary movements. However, research findings suggest that we are not always aware of the processes leading to movement execution. The present study investigated induced first-person access to inner processes of movement initiation and the underlying brain activities which contribute to the emergence of voluntary movement. Moreover, we investigated differences in task performance between mindfulness meditators and non-meditators while assuming that meditators are more experienced in attending to their inner processes. Two Libet-type tasks were performed; one in which participants were asked to press a button at a moment of their own decision, and the other one in which participants' attention was directed towards their inner processes of decision making regarding the intended movement which lead them to press the button. Meditators revealed a consistent readiness potential (RP) between the two tasks with correlations between the subjective intention time to act and the slope of the early RP. However, non-meditators did not show this consistency. Instead, elicited introspection of inner processes of movement initiation changed early brain activity that is related to voluntary movement processes. Our findings suggest that compared to non-meditators, meditators are more able to access the emergence of negative deflections of slow cortical potentials (SCPs), which could have fundamental effects on initiating a voluntary movement with awareness.

INTRODUCTION: Trait sexual motivation defines a psychological construct that reflects the long-lasting degree of motivation for sexual activities, which is assumed to be the result of biological and sociocultural influences. With this definition, it shares commonalities with other sexuality-related constructs like sexual desire, sexual drive, sexual needs, and sexual compulsivity. AIM: The Trait Sexual Motivation Questionnaire (TSMQ) was developed in order to measure trait sexual motivation with its different facets. METHODS: Several steps were conducted: First, items were composed assessing sexual desire, the effort made to gain sex, as well as specific sexual behaviors. Factor analysis of the data of a first sample (n = 256) was conducted. Second, the factor solution was verified by a confirmatory factor analysis in a second sample (n = 498) and construct validity was demonstrated. Third, the temporal stability of the TSMQ was tested in a third study (n = 59). MAIN OUTCOME MEASURE: Questionnaire data. RESULTS: The exploratory and confirmatory factor analyses revealed that trait sexual motivation is best characterized by four subscales: Solitary Sexuality, Importance of Sex, Seeking Sexual Encounters, and Comparison with Others. It could be shown that the test quality of the questionnaire is high. Most importantly for the trait concept, the retest reliability after 1 year was r = 0.87. CONCLUSION: Our results indicate that the TSMQ is indeed a suitable tool for measuring long-lasting sexual motivation with high test quality and high construct validity. A future differentiation between trait and state sexual motivation might be helpful for clinical as well as forensic research.

Cognitive reappraisal and expressive suppression, two major emotion regulation strategies, are differentially related to emotional well-being. The aim of this study was to test the association of individual differences in these two emotion regulation strategies with gray matter volume of brain regions that have been shown to be involved in the regulation of emotions. Based on high-resolution magnetic resonance images of 96 young adults voxel-based morphometry was used to analyze the gray matter volumes of the a priori regions of interest, including amygdala, insula, dorsal anterior cingulate and paracingulate cortex, medial and lateral prefrontal cortex (PFC) and their association with cognitive reappraisal and expressive suppression usage as well as neuroticism. A positive association of cognitive reappraisal with right and tendentially left amygdala volume and of neuroticism with left amygdala volume (marginally significant) was found. Expressive suppression was related to dorsal anterior cingulate/paracingulate cortex and medial PFC gray matter volume. The results of this study emphasize the important role of the amygdala in individual differences in cognitive reappraisal usage as well as neuroticism. Additionally, the association of expressive suppression usage with larger volumes of the medial PFC and dorsal anterior/paracingulate cortex underpins the role of these regions in regulating emotion-expressive behavior.

Cocaine-dependent individuals show altered brain activation during decision making. It is unclear, however, whether these activation differences are related to relapse vulnerability. This study tested the hypothesis that brain-activation patterns during reinforcement learning are linked to relapse 1 year later in individuals entering treatment for cocaine dependence. Subjects performed a Paper-Scissors-Rock task during functional magnetic resonance imaging (fMRI). A year later, we examined whether subjects had remained abstinent (n=15) or relapsed (n=15). Although the groups did not differ on demographic characteristics, behavioral performance, or lifetime substance use, abstinent patients reported greater motivation to win than relapsed patients. The fMRI results indicated that compared with abstinent individuals, relapsed users exhibited lower activation in (1) bilateral inferior frontal gyrus and striatum during decision making more generally; and (2) bilateral middle frontal gyrus and anterior insula during reward contingency learning in particular. Moreover, whereas abstinent patients exhibited greater left middle frontal and striatal activation to wins than losses, relapsed users did not demonstrate modulation in these regions as a function of outcome valence. Thus, individuals at high risk for relapse relative to those who are able to abstain allocate fewer neural resources to action-outcome contingency formation and decision making, as well as having less motivation to win on a laboratory-based task.

There is some evidence that neuroimaging can be used to predict relapse among abstinent methamphetamine-dependent (MD) individuals. However, it remains unclear what cognitive and neural processes contribute to relapse. This investigation examined whether insula activation during risk-taking decisions-a process shown to be disrupted in MD-is able to predict susceptibility for relapse. Sixty-eight MD enrolled in a treatment program during early abstinence completed a risk-taking task during functional magnetic resonance imaging. Sixty-three of the sixty-eight individuals were followed up 1 year after the study. Of these, 18 MD reported relapse. The 45 abstinent MD showed patterns of insula activation during risky decisions that resembled those found in prior studies of healthy controls, consisting of lower insula activation during safe decisions paired with higher activation during risky decisions. In contrast, the 18 relapsed MD showed similar insula activation during safe and risky decisions. An increase in one standard deviation in the difference in insula activation between risky and safe choices was associated with a 0.34 odds ratio for relapse at any given time. A median split of insula activation (difference between risky and safe) showed that individuals in the bottom half were two times more likely to relapse. In addition, a model that included several other brain regions increased prediction accuracy compared with insula-based model alone. These results suggest that failure to differentially activate the insula as a function of risk is a part of an altered risk-processing network associated with an increased susceptibility to relapse.

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.

This study addresses the controversy over how motor maps are organized during action simulation by examining whether action simulation states, that is, motor imagery and action observation, run on either effector-specific and/or action-specific motor maps. Subjects had to observe or imagine three types of movements effected by the right hand or the right foot with different action goals. The functional magnetic resonance imaging results showed an action-specific organization within premotor and posterior parietal areas of both hemispheres during action simulation, especially during action observation. There were also less pronounced effector-specific activation sites during both simulation processes. It is concluded that the premotor and parietal areas contain multiple motor maps rather than a single, continuous map of the body. The forms of simulation (observation, imagery), the task contexts (movements related to an object, with usual/unusual effector), and the underlying reason for performing the simulation (rate your subjective success afterwards) lead to the specific use of different representational motor maps within both regions. In our experimental setting, action-specific maps are dominant especially, during action observation, whereas effector-specific maps are recruited to only a lesser degree.