Dissociation of Proactive and Reactive Cognitive Control in Individuals with Schizotypy: An Event-Related Potential Study

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.

Abnormal theta and alpha oscillations in children and adolescents with first-episode psychosis and clinical high-risk psychosis

BACKGROUND

Cognitive control deficits are one of the main symptoms of psychosis. The basic neural oscillation patterns associated with cognitive control are already present in early adolescence. However, as previous studies have focused on adults with psychosis, it is unclear whether neurobiological impairments in cognitive control are present in children and adolescents with first-episode psychosis (FEP) or clinical high-risk (CHR) state for psychosis.

AIMS

To explore the deficits of electroencephalogram related to cognitive control tasks in children and adolescents with FEP and CHR.

METHOD

Electroencephalogram was recorded in untreated 48 patients with FEP, 24 patients with CHR and 42 healthy controls aged 10-17 years, while performing the visual oddball task. The N2 amplitude, theta and alpha oscillations were then analysed and compared between groups.

RESULTS

There was no significant group difference in N2 amplitude (P = 0.099). All groups showed increased theta and alpha oscillations relative to baseline before the stimulus in the frontal, central, left fronto-central and right fronto-central areas. These changes differed significantly between groups, with the FEP group showing significantly smaller theta (P < 0.001) and alpha (P < 0.01) oscillation than healthy controls. Theta and alpha oscillations in the CHR group did not differ significantly from the FEP group and healthy controls.

CONCLUSIONS

These results suggest that neural damage has already occurred in the early stage of psychosis, and that abnormal rhythmic activity of neurons may constitute the pathophysiological mechanism of cognitive dysfunction related to early-onset psychosis.

Cognitive control in creative discovery: The gap between ideal and reality

Creative discovery involves discovering the additional values of existing things in the environment by identifying the novel associations between seemingly unrelated things; the judgment made in this process is expected to be accurate but not entirely correct. From the perspective of cognitive processing, what is the difference between the ideal and real states of creative discovery? This is largely unknown. In this study, a daily life scenario was presented, and a great number of seemingly unrelated tools were presented for participants to discover valuable tools. Electrophysiological activity was recorded when participants identified tools, and we then retrospectively analyzed the differences between responses. Compared with usual tools, unusual tools evoked greater N2, N400 and late sustained potential (LSP) amplitudes, which was likely associated with the monitoring and resolution of cognitive conflicts. Moreover, unusual tools evoked smaller N400 and greater LSP amplitudes when correctly identified as usable than when identified as unusable; this result suggested that creative discovery in the ideal state should depend on the cognitive control involved in resolving conflicts. However, in the comparison between subjectively rated usable and unusable tools, smaller N400 and greater LSP amplitudes were observed only when unusual tools could be identified by expanding the application scope but not by releasing functional fixedness; this outcome suggested that creative discovery in the real state was not always influenced by the cognitive control involved in resolving conflicts. The difference in cognitive control that should be exerted and that was actually exerted to identify novel associations was discussed.

Proactive and reactive cognitive control for emotional conflict in individuals with high schizotypy: An ERP study

OBJECTIVE

The present study aimed to examine how individuals with high schizotypy, a high risk group of schizophrenia patients, resolve emotional conflict in proactive and reactive control and the underlying neural mechanisms.

METHODS

Thirty-two individuals with high schizotypy and 30 matched individuals with low schizotypy completed an emotional face-word Stroop task with electroencephalographic data recorded. The proportion of incongruent trials was manipulated in the task to induce proactive control (mostly incongruent trials context, MI context) or reactive control (mostly congruent trials context, MC context). Two event-related potential (ERP) components (N170 and N2) were examined, which represent face processing and cognitive control processes, respectively.

RESULTS

In the MC context, significantly decreased N2 and N170 amplitudes were found in high schizotypy individuals compared with low schizotypy individuals, suggesting abnormal neural activity of reactive control in high schizotypy individuals. No significant differences were found between the two groups in the MI context.

CONCLUSIONS

These results provide initial evidence for dissociation of neural activity of proactive and reactive control on emotional conflict in individuals with high schizotypy.

SIGNIFICANCE

The current findings provide important insight into the emotional conflict resolution in the schizophrenia spectrum.

Machine Learning Based on Event-Related EEG of Sustained Attention Differentiates Adults with Chronic High-Altitude Exposure from Healthy Controls

(1) Objective: The aim of this study was to examine the effect of high altitude on inhibitory control processes that underlie sustained attention in the neural correlates of EEG data, and explore whether the EEG data reflecting inhibitory control contain valuable information to classify high-altitude chronic hypoxia and plain controls. (2) Methods: 35 chronic high-altitude hypoxic adults and 32 matched controls were recruited. They were required to perform the go/no-go sustained attention task (GSAT) using event-related potentials. Three machine learning algorithms, namely a support vector machine (SVM), logistic regression (LR), and a decision tree (DT), were trained based on the related ERP components and neural oscillations to build a dichotomous classification model. (3) Results: Behaviorally, we found that the high altitude (HA) group had lower omission error rates during all observation periods than the low altitude (LA) group. Meanwhile, the ERP results showed that the HA participants had significantly shorter latency than the LAs for sustained potential (SP), indicating vigilance to response-related conflict. Meanwhile, event-related spectral perturbation (ERSP) analysis suggested that lowlander immigrants exposed to high altitudes may have compensatory activated prefrontal cortexes (PFC), as reflected by slow alpha, beta, and theta frequency-band neural oscillations. Finally, the machine learning results showed that the SVM achieved the optimal classification F1 score in the later stage of sustained attention, with an F1 score of 0.93, accuracy of 92.54%, sensitivity of 91.43%, specificity of 93.75%, and area under ROC curve (AUC) of 0.97. The results proved that SVM classification algorithms could be applied to identify chronic high-altitude hypoxia. (4) Conclusions: Compared with other methods, the SVM leads to a good overall performance that increases with the time spent on task, illustrating that the ERPs and neural oscillations may provide neuroelectrophysiological markers for identifying chronic plateau hypoxia.