A specific brain structural basis for individual differences in reality monitoring.

Much recent interest has centered on understanding the relationship between brain structure variability and individual differences in cognition, but there has been little progress in identifying specific neuroanatomical bases of such individual differences. One cognitive ability that exhibits considerable variability in the healthy population is reality monitoring; the cognitive processes used to introspectively judge whether a memory came from an internal or external source (e.g., whether an event was imagined or actually occurred). Neuroimaging research has implicated the medial anterior prefrontal cortex (PFC) in reality monitoring, and here we sought to determine whether morphological variability in a specific anteromedial PFC brain structure, the paracingulate sulcus (PCS), might underlie performance. Fifty-three healthy volunteers were selected on the basis of MRI scans and classified into four groups according to presence or absence of the PCS in their left or right hemisphere. The group with absence of the PCS in both hemispheres showed significantly reduced reality monitoring performance and ability to introspect metacognitively about their performance when compared with other participants. Consistent with the prediction that sulcal absence might mean greater volume in the surrounding frontal gyri, voxel-based morphometry revealed a significant negative correlation between anterior PFC gray matter and reality monitoring performance. The findings provide evidence that individual differences in introspective abilities like reality monitoring may be associated with specific structural variability in the PFC

Brain Mechanisms of Reality Monitoring

Reality monitoring processes are necessary for discriminating between internally generated information and information that originated in the outside world. They help us to identify our thoughts, feelings, and imaginations, and to distinguish them from events we may have experienced or have been told about by someone else. Reality monitoring errors range from confusions between real and imagined experiences, that are byproducts of normal cognition, to symptoms of mental illness such as hallucinations. Recent advances support an emerging neurocognitive characterization of reality monitoring that provides insights into its underlying operating principles and neural mechanisms, the differing ways in which impairment may occur in health and disease, and the potential for rehabilitation strategies to be devised that might help those who experience clinically significant reality monitoring disruption.Preparation of this article was supported by a James S. McDonnell Foundation Scholar Award to J.S.S., and by the University of Cambridge Behavioural and Clinical Neuroscience Institute, funded by a joint award from the Medical Research Council and the Wellcome Trust

Mentalizing the Self in Adolescence and its Links with Schizotypal Trait Expression

Contemporary research suggests that clinical psychosis is distally linked with schizotypal trait expression and more proximally with the breakdown of psychological processes pertaining to mentalizing. Although previous findings are suggestive of a relationship between trait-vulnerability for psychosis and mentalizing difficulties, they involve adult participants either within or beyond the critical period of illness onset. To date, little is known about the process of mentalizing during the critical developmental period of adolescence or its associations with schizotypal trait dimensions. In a series of empirical studies, the current thesis used novel experimental tasks and self-report measures in samples of typically-developing young people to: (1) examine the nature of associations linking schizotypal trait dimensions in adolescence to disruptions in mentalizing processes involving both the understanding of the self and others; (2) further understand the processes that sustain self-awareness during adolescence by examining the effects that age, cognitive effort and emotional valence may exert on self- and reality-monitoring performance; and (3) prospectively assess the nature of the relation between mentalizing processes sustaining self- (self-monitoring) and other-awareness (ToM) from adolescence to young adulthood. Overall, the findings of the current thesis provide novel data suggesting that he expression of schizotypal traits that impede interpersonal communication with others in adolescence are associated with difficulties in self and other understanding. Regarding the development of psychological processes sustaining self-awareness, current data suggest that although both self- and reality-monitoring abilities may be established in pre-adolescent development, reality-monitoring capacities for emotionally-charged material may undergo further elaboration from adolescence to young adulthood. In addition, the data of the current thesis suggest that increased cognitive effort and emotional valence during memory encoding may respectively lead to self- and reality-monitoring confusions. Finally, the findings of the current thesis suggest that different types of self-monitoring misattributions in adolescence can prospectively predict specific patterns of ToM dysfunction at 5-year follow-up

Schizotypy: environmental risk, genetic vulnerability, and neural correlates

Schizotypy is a unifying construct that draws a continuum between subclinical and clinical symptoms of psychotic disorders, reflected in commonly occurring cognitive, behavioural, and personality features. This thesis aims to carry out a holistic investigation of the genetic, neurocognitive, and environmental contributions to schizotypy in cohort of healthy individuals and those diagnosed with schizophrenia and bipolar disorder, to benefit from exploring the full range of schizotypal expressions. The main empirical chapters examine the impact of environmental factors and genetic vulnerability for schizophrenia on schizotypy and its component dimensions, with the final empirical chapter focused on the functional neural correlates of schizotypy during specific cognitive task. Participants for these studies were drawn from a cohort of 245 adults (mean age=38.58, sd=11.83, range=18.26 to 60.52), comprising 79 healthy controls, 86 individuals diagnosed with bipolar disorder, and 80 individuals diagnosed with schizophrenia. Study 1 reports positive associations between childhood trauma and schizotypy, while demonstrating the role of sociodemographic disadvantage as partial mediator of these associations. Study 2 reports that associations between childhood trauma and schizotypy are moderated by polygenic risk score for schizophrenia. Study 3 consisted of a systematic review of the available literature on structural and functional neural correlates of schizotypy. The high degree of methodological and conceptual heterogeneity across studies precluded the identification of a distinct pattern of schizotypy-associated brain alterations. Finally, Study 4 investigated the associations between schizotypy and brain activity during facial emotion processing using a data-driven approach. Overall, the findings from this thesis emphasised the relevance of investigating schizotypy in psychotic disorders, not restricted to schizophrenia, as well as the complex interaction between genetic and environmental risk factors in association with higher levels of schizotypy. Future research of schizotypy would be enhanced with utilization of longitudinal designs, with repeated measures of schizotypy over time, while incorporating data on exposure to childhood and adulthood environmental risk variables and genetic vulnerability. In addition, neuroimaging studies of schizotypy would benefit from multimodal, data-driven approaches, as well as being informed by environmental risk factors

The cognitive antecedents of psychosis-like (anomalous) experiences: variance within a stratified quota sample of the general population

In the general population, psychosis-like experiences have been extensively studied under the psychometric rubric of schizotypy (psychosis-proneness). As such, Phase 1 of this thesis aimed to assess the distribution of schizotypal traits and associated personality correlates displayed within a quota sample of the general population stratified by Gender and Ageband, the emphasis being upon anomalous experiences (positive schizotypy). Respondents (N = 130) completed a battery of established self-report measures assessing thirteen areas of personal experience. Correlational analysis revealed that eleven of the measures of ostensibly anomalous experiences possessed significant intercorrelations. Subsequent principal components analysis identified three factors accounting for 64.91% of the total variance; the factor accounting for the greatest proportion of variance (42.97%) was interpreted as representing a psychological disposition towards reporting ‘Anomalous Cognitions’. The other two factors are named ‘Lifeview System’ (12.60% of total variance) and ‘Social Adaptation Skills’ (9.34% of total variance). From the principal factor inclusion criteria for Phase 2 of the research are explicated. No significant mean Gender differences were revealed for the six self-report measures that provided unique contributions toward anomalous cognitions, the two self-report measures that uniquely contributed toward a lifeview system, or for the single self-report measure that uniquely contributed toward social adaptation skills. Additionally, four of the nine self-report measures which provided unique factorial contributions generated significant mean differences between Agebands, with a further three providing trends toward significant mean differences. Implications for the role of anomalous cognitions, a framework for a lifeview system, and social adaptation skills with regard to psychosis-proneness are discussed. From the primary factor (anomalous cognitions), three experimental groups were identified for cognitive testing: respondents scoring 1) ≤ 20th percentile; 2) 10% ± the mean; and 3) ≥ 80th percentile. This procedure provided a total of 78 participants (three x 26) for Phase 2 testing. Phase 2 of this thesis sought to identify some of the cognitive mechanisms underpinning subclinical anomalous cognitions with a view to deciphering which measures best predicted experimental group membership. A comprehensive literature review highlighted six domains of cognition, five accompanying self-report measures, and two measures of intelligence functioning (verbal and fluid/visuoconstructive), which, following previous research, were utilised as covariate measures. Based on prescribed delineation points, participants were allocated, according to scores on the primary factor from Phase 1, to one of three experimental groups (low-, mid, and high-anomalous cognitions). Of the six cognitive domains—1) sustained visual attention; 2) false (illusory) memory; 3) probability reasoning (decision making); 4) object recognition; 5) reality monitoring; and 6) self-monitoring—four succeeded in eliciting significant mean differences between experimental groups with the noted exceptions of sustained visual attention and self-monitoring. Subsequent canonical discriminant analyses identified that the best predictors of XPG membership were the number of critical lures recognised on the false memory test, the number of correct responses and confidence when uncertain on the object recognition test, plus two self-report measures pertaining to comorbid psychopathology and the vividness of visual imagery. In light of previous research, the inclusion of fasle (illusory) memory biases, the comorbidity of mental pathology (especially, depressive and anxiety-related symptoms), and the vividness of visual imagery are unsurprising; however, the two object recognition variables (the ‘number of correct responses’ and ‘confidence when uncertain’) offer exciting avenues for future research into the continuum of psychosis. Moreover, the ‘confidence when uncertain’ data from the object recognition test (perceptual) and the probability reasoning (decision making) data from the Beads test suggest that cognitive underconfidence may well be an enduring personality disposition in those reporting elevated levels of anomalous cognitions, including positive and disorganised schizotypal personality traits. The results of Phase 2 add confirmatory evidence to previous research suggestive of memory and perceptual biases plus comorbid psychopathology and the vividness of visual imagery as being integral to the psychogenesis of psychosis-like (anomalous) symptomatology

Neural correlates of reality monitoring during adolescence

Reality monitoring processes serve the critical function of discriminating between externally derived information and self-generated information. Several reality monitoring studies with healthy adult participants have identified the anterior prefrontal cortex (PFC) as consistently engaged during the recollection of self-generated contextual cues. Furthermore, reduced activity of medial PFC has been linked with schizotypal trait expression of delusion and hallucination-like symptoms in healthy adults undergoing fMRI reality-monitoring tasks. The present study seeks to examine the cerebral underpinnings of reality monitoring during adolescence, a developmental stage where the expression of schizotypal traits may increase risk for psychosis

Neural correlates of reality monitoring during adolescence

Reality monitoring processes serve the critical function of discriminating between externally derived information and self-generated information. Several reality monitoring studies with healthy adult participants have identified the anterior prefrontal cortex (PFC) as consistently engaged during the recollection of self-generated contextual cues. Furthermore, reduced activity of medial PFC has been linked with schizotypal trait expression of delusion and hallucination-like symptoms in healthy adults undergoing fMRI reality-monitoring tasks. The present study seeks to examine the cerebral underpinnings of reality monitoring during adolescence, a developmental stage where the expression of schizotypal traits may increase risk for psychosis.status: publishe