Human learning and memory depend on multiple cognitive systems related to dissociable brain structures. These systems interact not only in cooperative but also sometimes competitive ways in optimizing performance. Previous studies showed that manipulations reducing the engagement of frontal lobe-mediated explicit attentional processes could lead to improved performance in striatum-related procedural learning. In our study, hypnosis was used as a tool to reduce the competition between these 2 systems. We compared learning in hypnosis and in the alert state and found that hypnosis boosted striatum-dependent sequence learning. Since frontal lobe-dependent processes are primarily affected by hypnosis, this finding could be attributed to the disruption of the explicit attentional processes. Our result sheds light not only on the competitive nature of brain systems in cognitive processes but also could have important implications for training and rehabilitation programs, especially for developing new methods to improve human learning and memory performance.

Schizotypal personality traits are related to exposure to childhood trauma and to neurodevelopmental anomalies. Mentalization, attachment, openness, intellect, and social support are factors that may mediate or buffer the effect of such risk factors. However, to date, no study has investigated the associations between these constructs and schizotypy in a single model. We collected data in a large and demographically heterogeneous general population sample (N = 3441, 68% female, mean age = 39 years). We assessed schizotypal traits, environmental factors such as early traumas and perceived social support during adolescence, and putative mediators and protective factors such as openness/intellect, mentalization, and attachment. We estimated a Gaussian Graphical Model to examine the complex multivariate associations between the above constructs. Bootstrapping showed that the model was reliable. The importance of nodes was inferred using node centralities. Mentalization, disorganized schizotypy, and PTSD-like symptoms were the most central nodes in terms of strength and closeness. Disorganized schizotypy was related to early developmental anomalies, positive and negative schizotypy, and reduced intellect, mentalization was primarily related to reduced attachment avoidance and anxiety, while PTSD-like symptoms were linked to traumas and attachment anxiety. The results are in line with theories that emphasize the importance of mentalization and disorganized schizotypy in outcomes related to the extended psychosis-spectrum phenotypes. The findings may facilitate the generation of hypotheses for prospective and intervention studies.

Memory dysfunction has been first recognized in patients with schizophrenia over 100 years ago and it is considered to be a particularly pronounced symptom of the illness. According to the hippocampal dysfunction theory, memory impairments and positive symptoms of schizophrenia such as hallucinations and delusions might be attributable to an unbalance in the interplay of pattern separation and pattern completion neural computations. While the theory addresses alterations specifically related to schizophrenia, schizotypy (a personality construct that encompasses schizophrenia symptom-like traits) is increasingly considered to be a useful construct for conceptualizing the development and expression of schizophrenia. Behavioural studies in patients with schizophrenia have come to disparate findings when testing the hippocampal dysfunction theory and are not devoid of some of the limitations and confounds that are commonly encountered in schizophrenia research, such as small samples, and a possible modulating effect of medications on cognitive performance. The present study aims to reconcile this debate by investigating the relationship between positive schizotypy and lure discrimination index and false recognition of lures (putative behavioural indicators of pattern separation and completion, respectively) in a sample of healthy individuals (N=71) varying in terms of self-reported unusual experiences. Contradicting our expectations (which were based on patient studies), positive schizotypy in the healthy population was associated with enhanced mnemonic discrimination and attenuated false recognition of lures. The current study is the first ever to investigate pattern separation and pattern completion in relation to different schizotypy dimensions. We address possible underlying mechanisms that might cause a lower false recognition of lures (e.g. impaired ability to generalise) in schizotypy. Resemblance between positive schizotypy and schizophrenia could not be detected at the level of behavioural performance which can be interpreted in a theoretical framework of hippocampal neural computations . Uncovering the underlying mechanisms of this discrepancy awaits future research.