Investigating the impact of schizophrenia traits on attention: the role of the theta band in a modified Posner cueing paradigm.

Joint attention is an indispensable tool for daily communication. Abnormalities in joint attention may be a key reason underlying social impairment in schizophrenia spectrum disorders. In this study, we aimed to explore the attentional orientation mechanism related to schizotypal traits in a social situation. Here, we employed a Posner cueing paradigm with social attentional cues. Subjects needed to detect the location of a target that is cued by gaze and head orientation. The power in the theta frequency band was used to examine the attentional process in the schizophrenia spectrum. There were four main findings. First, a significant association was found between schizotypal traits and attention orientation in response to invalid gaze cues. Second, individuals with schizotypal traits exhibited significant activation of neural oscillations and synchrony in the theta band, which correlated with their schizotypal tendencies. Third, neural oscillations and synchrony demonstrated a synergistic effect during social tasks, particularly when processing gaze cues. Finally, the relationship between schizotypal traits and attention orientation was mediated by neural oscillations and synchrony in the theta frequency band. These findings deepen our understanding of the impact of theta activity in schizotypal traits on joint attention and offer new insights for future intervention strategies.

Comparison of trait and state mind wandering among schizotypal, subclinically depressed, and control individuals.

BACKGROUND: Mind wandering is a common phenomenon in daily life. However, the manifestations and cognitive correlates of mind wandering in different subclinical populations remain unclear. In this study, these aspects were examined in individuals with schizotypal traits and individuals with depressive symptoms, i.e., subclinical populations of patients with schizophrenia and depression. METHODS: Forty-two individuals with schizotypal traits, 42 individuals with subclinical depression, and 42 controls were recruited to complete a mind wandering thought sampling task (state level) and a mind wandering questionnaire (trait level). Measures of rumination and cognitive functions (attention, inhibition, and working memory) were also completed by participants. RESULTS: Both subclinical groups exhibited more state and trait mind wandering than did the control group. Furthermore, individuals with schizotypal traits demonstrated more trait mind wandering than individuals with subclinical depression. Rumination, sustained attention, and working memory were associated with mind wandering. In addition, mind wandering in individuals with subclinical depression can be accounted for by rumination or attention, while mind wandering in individuals with high schizotypal traits cannot be accounted for by rumination, attention, or working memory. CONCLUSIONS: The results suggest that individuals with high schizotypal traits and subclinical depression have different patterns of mind wandering and mechanisms. These findings have implications for understanding the unique profile of mind wandering in subclinical individuals.

Nonclinical psychotic-like experiences and schizotypy dimensions: Associations with hippocampal subfield and amygdala volumes.

Schizotypy and psychotic-like experiences (PLE) form part of the wider psychosis continuum and may have brain structural correlates in nonclinical cohorts. This study aimed to compare the effects of differential schizotypy dimensions, PLE, and their interaction on hippocampal subfields and amygdala volumes in the absence of clinical psychopathology. In a cohort of 367 psychiatrically healthy individuals, we assessed schizotypal traits using the Oxford-Liverpool Inventory of Life Experiences (O-LIFE) and PLE using the short form of the Prodromal Questionnaire (PQ-16). Based on high-resolution structural MRI scans, we used automated segmentation to estimate volumes of limbic structures. Sex and total intracranial volume (Step 1), PLE and schizotypy dimensions (Step 2), and their interaction terms (Step 3) were entered as regressors for bilateral amygdala and hippocampal subfield volumes in hierarchical multiple linear regression models. Positive schizotypy, but not PLE, was negatively associated with left amygdala and subiculum volumes. O-LIFE Impulsive Nonconformity, as well as the two-way interaction between positive schizotypy and PLE, were associated with larger left subiculum volumes. None of the estimators for right hemispheric hippocampal subfield volumes survived correction for multiple comparisons. Our findings support differential associations of hippocampus subfield volumes with trait dimensions rather than PLE, and support overlap and interactions between psychometric positive schizotypy and PLE. In a healthy cohort without current psychosis risk syndromes, the positive association between PLE and hippocampal subfield volume occurred at a high expression of positive schizotypy. Further studies combining stable, transient, and genetic parameters are required.

Self-perceived cognitive lapses and psychological well-being in schizotypy: Generalized and domain-specific associations.

A critical link between schizotypy and schizophrenia is impoverished cognitive functioning. In the majority of studies, though: (1) cognition is examined with standard neuropsychological tasks; and (2) high-schizotypal individuals are defined according to criteria applied in the respective study sample. Taking these considerations into account, the aims of the present study were to examine: (1) differences between four pre-defined, according to normative criteria, schizotypal (paranoid, negative, disorganized and cognitive-perceptual) and one control groups in self-perceived cognitive lapses; and (2) associations between schizotypal dimensions, self-perceived cognitive lapses and psychological well-being. Two hundred and sixty-one participants were administered the Schizotypal Personality Questionnaire, the Cognitive Failures Questionnaire (CFQ) and the Flourishing Scale, which assesses psychological well-being. Negative schizotypals reported higher scores in almost all CFQ measures compared with the control group (all p values < 0.01) along with poorer psychological well-being compared with the control and the cognitive-perceptual groups (both p values < 0.001). The disorganized group had higher scores in distractibility, blunders and total CFQ scores compared with the control group (all p values < 0.001). High psychological well-being was significantly associated with low negative schizotypy and CFQ blunders along with high cognitive-perceptual schizotypy (all p values < 0.05). To summarize, negative schizotypy is associated with a profile of "generalized" self-perceived cognitive lapses while disorganized schizotypy is characterized by self-perceived cognitive slips that have previously been shown to be mediated by a fronto-parietal network. Although psychological well-being is negatively associated with social-context specific cognitive failures and negative schizotypy, it is positively associated with cognitive-perceptual schizotypy.

Selectively reduced contrast sensitivity in high schizotypy.

Deficits in the ability to encode small differences in contrast between adjacent parts of an image (contrast sensitivity) are well documented in schizophrenic patients. In the present study, we sought to determine whether contrast sensitivity deficits reported in schizophrenic patients are also evident in those who exhibit high schizotypy scores in a typical (i.e., non-schizophrenic) population. Using the O-Life Questionnaire, we determined the effects of schizotypy on spatial (0.5, 2 and 8 c/deg) and spatiotemporal (0.5 and 8 c/deg at 0.5 and 8 Hz) contrast sensitivity in 73 young (18-26 years), majority female (n = 68) participants. We found differences in contrast sensitivity that were spatial, spatiotemporal and O-Life subscale specific. Spatial contrast sensitivity was significantly lower in high, compared to low schizotypes at low spatial frequencies (0.5 c/deg) in those who scored highly on the Unusual Experiences and Cognitive Disorganisation O-Life subscales. For moving stimuli, individuals with high scores on the Unusual Experiences subscale exhibited lower spatiotemporal contrast sensitivity for 0.5 and 8 c/deg patterns drifting at 8 Hz. Although the effects reported here were relatively small, this is the first report of reduced contrast sensitivity in schizotypy.

Anhedonia in adolescents at ultra-high risk (UHR) of psychosis: findings from a 1-year longitudinal study.

Previous findings suggested deficits in pleasure experience in schizophrenia, but little is known in psychosis risk prodrome, especially in adolescence. Aim of this study was (1) to assess anhedonia in distinct help-seeking subgroups of adolescents identified through the ultra-high risk (UHR) criteria, (2) to explore any association of anhedonia with other psychopathological aspects in the UHR group, and (3) to monitor longitudinally the stability of anhedonia in UHR individuals across 1-year follow-up period. 123 participants (13-18 years) completed the Comprehensive Assessment of At-Risk Mental States (CAARMS), the Beck Depression Inventory-II, the Schizotypal Personality Questionnaire-Brief version, the Brief-O-LIFE questionnaire (BOL), and the Brief version of the World Health Organization Quality of Life scale (WHOQOL-BREF). Two different indexes of anhedonia were used: CAARMS "Anhedonia" item 4.3 and BOL "Introvertive Anhedonia" subscale scores. No difference in anhedonia levels between UHR and First Episode Psychosis (FEP) groups was found. UHR adolescents showed higher CAARMS and BOL anhedonia scores than non-UHR/FEP. After 1-year follow-up period, UHR adolescents had a significant decrease in severity only in CAARMS anhedonia subscores. In UHR subgroup, CAARMS anhedonia measures showed significant correlations with impaired role functioning and negative symptoms, while BOL anhedonia was significantly correlated with specific schizotypal personality traits concerning interpersonal deficits. Anhedonia is prominent in the psychosis prodrome, also in adolescence. Its severity is not statistically different from that of FEP adolescents and is related to more severe functioning impairment and a worse quality of life.

Schizophrenia-spectrum psychopathology in obsessive-compulsive disorder: an empirical study.

The differential diagnosis of obsessive-compulsive disorder (OCD) and schizophrenia-spectrum disorders can be difficult. In the current diagnostic criteria, basic concepts such as obsession and delusion overlap. This study examined lifetime schizophrenia-spectrum psychopathology, including subtle schizotypal symptomatology and subjective anomalies such as self-disorders, in a sample diagnosed with OCD in a specialized setting. The study also examined the differential diagnostic potential of the classic psychopathological notions of true obsession ('with resistance') and pseudo-obsession. The study involved 42 outpatients diagnosed with OCD at two clinics specialized in the treatment of OCD. The patients underwent semi-structured, narrative interviews assessing a comprehensive battery of psychopathological instruments. The final lifetime research-diagnosis was based on a consensus between a senior clinical psychiatrist and an experienced research clinician. The study found that 29% of the patients fulfilled criteria of schizophrenia or another non-affective psychosis as main, lifetime DSM-5 research-diagnosis. Another 33% received a research-diagnosis of schizotypal personality disorder, 10% a research-diagnosis of major depression and 29% a main research-diagnosis of OCD. Self-disorders aggregated in the schizophrenia-spectrum groups. True obsessions had a specificity of 93% and a sensitivity of 58% for a main diagnosis of OCD. In conclusion, a high proportion of clinically diagnosed OCD patients fulfilled diagnostic criteria of a schizophrenia-spectrum disorder. The conspicuous obsessive-compulsive symptomatology may have resulted in a disregard of psychotic symptoms and other psychopathology. Furthermore, the differentiation of obsessions from related psychopathological phenomena is insufficient and a conceptual and empirical effort in this domain is required in the future.

Exploring schizophrenia spectrum psychopathology in borderline personality disorder.

We have previously argued that the current borderline personality disorder (BPD) diagnosis is over-inclusive and clinically and conceptually impossible to distinguish from the schizophrenia spectrum disorders. This study involves 30 patients clinically diagnosed with BPD as their main diagnosis by three BPD dedicated outpatient treatment facilities in Denmark. The patients underwent a careful and time-consuming psychiatric evaluation involving several senior level clinical psychiatrists and researchers and a comprehensive battery of psychopathological scales. The study found that the vast majority of patients (67% in DSM-5 and 77% in ICD-10) in fact met the criteria for a schizophrenia spectrum disorder, i.e., schizophrenia (20%) or schizotypal (personality) disorder (SPD). The schizophrenia spectrum group scored significantly higher on the level of disorders of core self as measured by the Examination of Anomalous Self-Experiences Scale (EASE). The BPD criterion of "identity disturbance" was significantly correlated with the mean total score of EASE. These findings are discussed in the light of changes from prototypical to polythetic diagnostic systems. We argue that the original prototypes/gestalts informing the creation of BPD and SPD have gone into oblivion during the evolution of polythetic criteria.

Interrogating the Relationship Between Schizotypy, the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism, and Neuronal Oscillatory Activity.

The COMT Val158Met polymorphism affects the availability of synaptic dopamine in the prefrontal cortex and has been widely studied as a genetic risk factor for psychosis. Schizotypy is associated with an increased risk of psychosis, with some studies implicating similar neurobiological mechanisms to schizophrenia. The present study sought to interrogate the link between the COMT Val158Met polymorphism and schizotypy using electroencephalogram (EEG) to identify neurophysiological mechanisms underpinning psychosis risk. Neurotypical (N = 91) adults were genotyped for the COMT Val158Met polymorphism, completed the Schizotypal Personality Questionnaire (SPQ), and had eyes open resting-state EEG recorded for 4 min. SPQ suspiciousness subscale scores were higher for individuals homozygous for Val/Val and Met/Met versus Val/Met genotypes. Delta, theta, alpha-2, beta-1, and beta-2 amplitudes were lower for Val/Val than Met/Met individuals. Lower theta amplitudes were correlated with higher total SPQ scores (P = 0.050), and multiple regression revealed that higher delta, and lower theta and beta-2 amplitudes (but not COMT genotype) best predicted total SPQ scores (P = 0.014). This study demonstrates the importance of COMT genotype in determining trait suspiciousness and EEG oscillatory activity. It also highlights relationships between dopaminergic alterations, EEG and schizotypy that are dissimilar to those observed in schizophrenia.

Individual differences in sensory integration predict differences in time perception and individual levels of schizotypy.

To interact functionally with our environment, our perception must locate events in time, including discerning whether sensory events are simultaneous. The Temporal Binding Window (TBW; the time window within which two stimuli tend to be integrated into one event) has been shown to relate to individual differences in perception, including schizotypy, but the relationship with subjective estimates of duration is unclear. We compare individual TBWs with individual differences in the filled duration illusion, exploiting differences in perception between empty and filled durations (the latter typically being perceived as longer). Schizotypy has been related to both these measures and is included to explore a potential link between these tasks and enduring perceptual differences. Results suggest that individuals with a narrower TBW make longer estimates for empty durations and demonstrate less variability in both conditions. Exploratory analysis of schizotypy data suggests a relationship with the TBW but is inconclusive regarding time perception.

Aberrant personality tendencies and academic success throughout engineering education.

OBJECTIVE: In a longitudinal field study, we investigated the predictive associations between six aberrant personality tendencies (schizotypal, avoidant, borderline, antisocial, narcissistic, obsessive-compulsive) and academic success of science, technology, engineering, and mathematics students. METHOD: Bachelor students of Industrial Engineering at a Dutch technical university (N = 432, Mage  = 18.45; 87.3% male) filled out the NEO-PI-R and aberrant tendencies were operationalized by the five-factor model (FFM) compound technique. Indicators of academic achievement (grades) and persistence (credit points earned per year, re-enrollment, study duration) were made available by the academic office. RESULTS: Validities across the 3 years of the study program consistently support the role of two aberrant tendencies: Individuals with high antisocial tendency reached lower academic achievement, took longer to finish their study, and had a higher risk of dropout. The obsessive-compulsive tendency was associated with higher grade-point average, faster study progress, and higher retention rates and effects were still visible while controlling for known predictors (high school grades, Conscientiousness). Contrary to our expectations, we found no evidence for inverted U-shaped relationships. CONCLUSIONS: We used the compound technique for aberrant tendencies based on the FFM in the academic context and our findings support the importance of personality-based psychopathological tendencies for academic success.

Self-Monitoring for speech and its links to age, cognitive effort, schizotypal trait expression and impulsivity during adolescence.

Introduction: Disruptions in self-monitoring processes represent key cognitive factors associated with schizophrenia spectrum disorders. In the current study, we assessed the effects of age and cognitive effort on self-monitoring for speech in adolescence, as well as its associations with personality dimensions pertaining to schizotypy and impulsivity.Methods: 121 community adolescents undertook a self-monitoring task that assesses the capacity to discriminate between self-generated overt and silent speech, for items requiring different levels of cognitive effort. Self-report measures were used to assess trait dimensions of schizotypy and impulsivity.Results: Cognitive effort, but not age, contributed to the overall rate of self-monitoring errors. Contrary to clinical psychosis and high risk samples, increased cognitive effort in healthy adolescents led to more internalising than externalising self-monitoring errors. Higher scores on the interpersonal dimension of schizotypy were associated with increases in the total rate of self-monitoring errors. No associations were found between positive schizotypy and externalising self-monitoring misattributions. Finally, trait impulsivity dimensions were not associated with self-monitoring performance.Conclusions: The present findings suggest that self-monitoring confusions may be linked to trait-risk for psychosis in adolescence. Future studies can prospectively assess whether the association between negative schizotypal traits and self-monitoring represents a distal marker of psychosis vulnerability.

The association of schizotypal traits with Prepulse Inhibition: a double approach exploration.

Introduction: According to the fully-dimensional approach, schizotypy is a personality trait present in the population in a continuous manner while the quasi-dimensional approach emphasises its extreme presentations. In this study we examined the relationship between sensorimotor gating, a core risk-index of the schizophrenia-spectrum, and four schizotypal factors in a dimensional-wise and a dichotomising-wise approach. Methods: Two-hundred and eighty-three participants were assessed with the Schizotypal Personality Questionnaire and were tested for Prepulse Inhibition (PPI). Associations between the schizotypal factors and startle measures were examined with stepwise regressions (dimensional-wise approach). Individuals in the lower 20% or the upper 20% for each schizotypal factor were identified and between-group comparisons were conducted (dichotomising-wise approach). Results: We found that with both approaches, only high paranoid or negative schizotypy were associated with reduced PPI. The low negative schizotypy group had prolonged onset and peak latencies, indicating that prolonged stimulus detection accompanies superior sensorimotor gating in this group. Conclusions: The findings suggest that although differentiating the effects of the various schizotypal factors is primary, the approach employed is secondary. The study also adds evidence in the literature supporting PPI as a useful endophenotypic marker of the schizophrenia-spectrum and highlights the contribution of specific aspects of schizotypy.

Is perception the missing link between creativity, curiosity and schizotypy? Evidence from spontaneous eye-movements and responses to auditory oddball stimuli.

What is the relationship between creativity, curiosity, and schizotypy? Schizophrenia-spectrum conditions and creativity have been linked to deficits in filtering sensory information, and curiosity is associated with information-seeking. This raises the possibility of a perception-based link between all three concepts. Here, we investigated whether the same individual differences in perceptual encoding explain variance in creativity, curiosity, and schizotypy. We administered an active auditory oddball task and a free viewing eye-tracking paradigm (N = 88). Creativity was measured with the figural portion of the Torrance Tests of Creative Thinking (TTCT) and two self-report scales. Schizotypy and curiosity were measured with self-reports. We found that creativity was associated with increased reaction time to the rare tone in the oddball task and was positively associated with the number and duration of fixations in the free viewing task. Schizotypy, on the other hand, showed a negative trend with the number and duration of fixations. Both creativity and curiosity were positively associated with explorative eye movements (unique number of regions visited) and Shannon entropy, while schizotypy was negatively associated with entropy. We further compared saliency maps finding that individuals high versus low in creativity and curiosity, respectively, exhibit differences in where they look. These findings may suggest a perception-based link between creativity and curiosity, but not schizotypy. Implications and limitations of these findings are discussed.

Psychosis risk is associated with decreased resting-state functional connectivity between the striatum and the default mode network.

Psychosis is linked to aberrant salience or to viewing neutral stimuli as self-relevant, suggesting a possible impairment in self-relevance processing. Psychosis is also associated with increased dopamine in the dorsal striatum, especially the anterior caudate (Kegeles et al., 2010). Critically, the anterior caudate is especially connected to (a) the cortical default mode network (DMN), centrally involved in self-relevance processing, and (b) to a lesser extent, the cortical frontoparietal network (FPN; Choi, Yeo, & Buckner, 2012). However, no previous study has directly examined striatal-cortical DMN connectivity in psychosis risk. In Study 1, we examined resting-state functional connectivity in psychosis risk (n = 18) and control (n = 19) groups between (a) striatal DMN and FPN subregions and (b) cortical DMN and FPN. The psychosis risk group exhibited decreased connectivity between the striatal subregions and the cortical DMN. In contrast, the psychosis risk group exhibited intact connectivity between the striatal subregions and the cortical FPN. Additionally, recent distress was also associated with decreased striatal-cortical DMN connectivity. In Study 2, to determine whether the decreased striatal-cortical DMN connectivity was specific to psychosis risk or was related to recent distress more generally, we examined the relationship between connectivity and distress in individuals diagnosed with nonpsychotic emotional distress disorders (N = 25). In contrast to Study 1, here we found that distress was associated with evidence of increased striatal-cortical DMN connectivity. Overall, the present results suggest that decreased striatal-cortical DMN connectivity is associated with psychosis risk and could contribute to aberrant salience.

Integrated assessment of visual perception abnormalities in psychotic disorders and relationship with clinical characteristics.

BACKGROUND: The visual system is recognized as an important site of pathology and dysfunction in schizophrenia. In this study, we evaluated different visual perceptual functions in patients with psychotic disorders using a potentially clinically applicable task battery and assessed their relationship with symptom severity in patients, and with schizotypal features in healthy participants. METHODS: Five different areas of visual functioning were evaluated in patients with schizophrenia and schizoaffective disorder (n = 28) and healthy control subjects (n = 31) using a battery that included visuospatial working memory (VSWM), velocity discrimination (VD), contour integration, visual context processing, and backward masking tasks. RESULTS: The patient group demonstrated significantly lower performance in VD, contour integration, and VSWM tasks. Performance did not differ between the two groups on the visual context processing task and did not differ across levels of interstimulus intervals in the backward masking task. Performances on VSWM, VD, and contour integration tasks were correlated with negative symptom severity but not with other symptom dimensions in the patient group. VSWM and VD performances were also correlated with negative sychizotypal features in healthy controls. CONCLUSION: Taken together, these results demonstrate significant abnormalities in multiple visual processing tasks in patients with psychotic disorders, adding to the literature implicating visual abnormalities in these conditions. Furthermore, our results show that visual processing impairments are associated with the negative symptom dimension in patients as well as healthy individuals.

Deficits in context-dependent adaptive coding in early psychosis and healthy individuals with schizotypal personality traits.

Adaptive coding of information is a fundamental principle of brain functioning. It allows for efficient representation over a large range of inputs and thereby alleviates the limited coding range of neurons. In the present study, we investigated for the first time potential alterations in context-dependent reward adaptation and its association with symptom dimensions in the schizophrenia spectrum. We studied 27 patients with first-episode psychosis, 26 individuals with schizotypal personality traits and 25 healthy controls. We used functional MRI in combination with a variant of the monetary incentive delay task and assessed adaptive reward coding in two reward conditions with different reward ranges. Compared to healthy controls, patients with first-episode psychosis and healthy individuals with schizotypal personality traits showed a deficit in increasing the blood oxygen level-dependent response slope in the right caudate for the low reward range compared to the high reward range. In other words, the two groups showed inefficient neural adaptation to the current reward context. In addition, we found impaired adaptive coding of reward in the caudate nucleus and putamen to be associated with total symptom severity across the schizophrenia spectrum. Symptom severity was more strongly associated with neural deficits in adaptive coding than with the neural coding of absolute reward outcomes. Deficits in adaptive coding were prominent across the schizophrenia spectrum and even detectable in unmedicated (healthy) individuals with schizotypal personality traits. Furthermore, the association between total symptom severity and impaired adaptive coding in the right caudate and putamen suggests a dimensional mechanism underlying imprecise neural adaptation. Our findings support the idea that impaired adaptive coding may be a general information-processing deficit explaining disturbances within the schizophrenia spectrum over and above a simple model of blunted absolute reward signals.

Schizotypy and smooth pursuit eye movements as potential endophenotypes of obsessive-compulsive disorder.

Patients with obsessive-compulsive disorder (OCD) show dysfunctions of the fronto-striatal circuitry, which imply corresponding oculomotor deficits including smooth pursuit eye movements (SPEM). However, evidence for a deficit in SPEM is inconclusive, with some studies reporting reduced velocity gain while others did not find any SPEM dysfunctions in OCD patients. Interestingly, psychosis-like traits have repeatedly been linked to both OCD and impaired SPEM. Here, we examined a large sample of n = 168 patients with OCD, n = 93 unaffected first-degree relatives and n = 171 healthy control subjects to investigate whether elevated levels of schizotypy and SPEM deficits represent potential endophenotypes of OCD. We applied a SPEM task with high demands on predictive pursuit that is more sensitive to assess executive dysfunctions than a standard task with continuous visual feedback, as episodes of target blanking put increased demands on basal ganglia and prefrontal involvement. Additionally, we examined the relation between schizotypy and SPEM performance in OCD patients and their relatives. Results indicate that OCD patients and unaffected relatives do not show deficient performance in either standard or predictive SPEM. Yet, both patients and relatives exhibited elevated levels of schizotypy, and schizotypy was significantly correlated with velocity gain during standard trials in unmedicated and depression-free OCD patients. These findings highlight the role of schizotypy as a candidate endophenotype of OCD and add to the growing evidence for predisposing personality traits in OCD. Furthermore, intact gain may represent a key characteristic that distinguishes the OCD and schizophrenia patient populations.

Environmental control and psychosis-relevant traits modulate the prospective sense of agency in non-clinical individuals.

The sense of agency concerns the experience of being the source of one's own actions and their consequences. An altered sense of agency can occur due to task automation and in psychosis. We tested in a non-clinical sample the hypothesis that reducing voluntary task control diminishes intentional binding as an implicit indicator of the sense of agency, possibly interacting with psychosis-relevant personality traits. Agent-device interactions were manipulated obtaining positive-control (voluntary interaction), no-control (automation), and negative-control (device-commanded interaction) groups. The main results showed reduced prospective intentional binding (predictive coding of action consequences) in the no-control and negative-control groups, compared to the positive-control group. Psychosis-like experiences covaried positively with intentional binding in the no-control group, but negatively in the negative-control group. Moreover, positive-social traits were associated with increased intentional binding in the positive-control group. These findings demonstrate the interplay between environmental and individual differences variables in establishing the implicit sense of agency.

Increased resting perfusion of the hippocampus in high positive schizotypy: A pseudocontinuous arterial spin labeling study.

Arterial spin labeling (ASL) provides absolute quantification of resting tissue cerebral blood flow (CBF) as an entirely noninvasive approach with good reproducibility. As a result of neurovascular coupling, ASL provides a useful marker of resting neuronal activity. Recent ASL studies in individuals at clinical high risk of psychosis (CHR) have reported increased resting hippocampal perfusion compared with healthy controls. Schizotypy refers to the presence of subclinical psychotic-like experiences in healthy individuals and represents a robust framework to study neurobiological mechanisms involved in the extended psychosis phenotype while avoiding potentially confounding effects of antipsychotic medications or disease comorbidity. Here we applied pseudo-continuous ASL to examine differences in resting CBF in 21 subjects with high positive schizotypy (HS) relative to 22 subjects with low positive schizotypy (LS), as determined by the Oxford and Liverpool Inventory of Feelings and Experiences. Based on preclinical evidence that hippocampal hyperactivity leads to increased activity in mesostriatal dopamine projections, CBF in hippocampus, midbrain, and striatum was assessed. Participants with HS showed higher CBF of the right hippocampus compared to those with LS (p = .031, family-wise error corrected). No differences were detected in the striatum or midbrain. The association between increased hippocampal CBF and HS supports the notion that hippocampal hyperactivity might be a central characteristic of the extended psychosis phenotype, while hyperactivity in subcortical dopamine pathways may only emerge at a higher intensity of psychotic experiences.