Electrophysiological correlates of visual backward masking in high schizotypic personality traits participants

People with high schizotypy experience more illusions in the Pattern Glare Test: Consistent with the hyperexcitability hypothesis

Individuals diagnosed with schizophrenia spectrum disorders (SSD) exhibit a constellation of sensory and perceptual impairments, including hyporeactivity to external input. However, individuals with SSD also report subjective experiences of sensory flooding, suggesting sensory hyperexcitability. To identify the extent to which behavioural indices of hyperexcitability are related to non-psychotic symptoms of schizophrenia, we tested a non-clinical population measured for schizophrenia-like traits (schizotypy), and a behavioural measure of sensory hyperexcitability, specifically the number of illusions seen in the Pattern Glare Test. Two samples totaling 913 individuals completed an online version of the Schizotypal Personality Questionnaire - Brief Revised (SPQ-BR) and the Pattern Glare Test. Individuals with higher schizotypy traits reported more illusions in the Pattern Glare Test. Additionally, one of the three SPQ-BR factors, the disorganized factor, significantly predicted the number of illusions reported. These data illustrate the potential for research in non-clinical samples to inform clinically relevant research.

Recruited macrophages that colonize the post-inflammatory peritoneal niche convert into functionally divergent resident cells

Inflammation generally leads to recruitment of monocyte-derived macrophages. What regulates the fate of these cells and to what extent they can assume the identity and function of resident macrophages is unclear. Here, we show that macrophages elicited into the peritoneal cavity during mild inflammation persist long-term but are retained in an immature transitory state of differentiation due to the presence of enduring resident macrophages. By contrast, severe inflammation results in ablation of resident macrophages and a protracted phase wherein the cavity is incapable of sustaining a resident phenotype, yet ultimately elicited cells acquire a mature resident identity. These macrophages also have transcriptionally and functionally divergent features that result from inflammation-driven alterations to the peritoneal cavity micro-environment and, to a lesser extent, effects of origin and time-of-residency. Hence, rather than being predetermined, the fate of inflammation-elicited peritoneal macrophages seems to be regulated by the environment.

Electrophysiological correlates of visual backward masking in patients with bipolar disorder

In visual backward masking (VBM), a target is followed by a mask that decreases target discriminability. Schizophrenia patients (SZ) show strong and reproducible masking impairments, which are associated with reduced EEG amplitudes. Patients with bipolar disorder (BP) show masking deficits, too. Here, we investigated the neural EEG correlates of VBM in BP. 122 SZ, 94 unaffected controls, and 38 BP joined a standard VBM experiment. 123 SZ, 94 unaffected controls and 16 BP joined a corresponding EEG experiment, analyzed in terms of global field power. As in previous studies, SZ and BP show strong masking deficits. Importantly and similarly to SZ, BP show decreased global field power amplitudes at approximately 200 ms after the target onset, compared to controls. These results suggest that VBM deficits are not specific for schizophrenia but for a broader range of functional psychoses. Potentially, both SZ and BP show deficient target enhancement.

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.

Neural Compensation Mechanisms of Siblings of Schizophrenia Patients as Revealed by High-Density EEG

Visual backward masking (VBM) deficits are candidate endophenotypes of schizophrenia indexing genetic liability of the disorder. In VBM, a target is followed by a mask that deteriorates target perception. Schizophrenia patients and, to a lesser extent, their unaffected relatives show strong and reproducible VBM deficits. In patients, VBM deficits are associated with strongly decreased amplitudes in the evoked-related potentials (ERPs). Here, to unveil the neural mechanisms of VBM in schizophrenia, circumventing illness-specific confounds, we investigated the electroencephalogram correlates of VBM in unaffected siblings of schizophrenia patients. We tested 110 schizophrenia patients, 60 siblings, and 83 healthy controls. As in previous studies, patients showed strong behavioral deficits and decreased ERP amplitudes compared to controls. Surprisingly, the ERP amplitudes of siblings were even higher than the ones of controls, while their performances were similar. ERP amplitudes in siblings were found to correlate with performance. These results suggest that VBM is deteriorated in patients and siblings. However, siblings, unlike patients, can partially compensate for the deficits by over-activating a network of brain regions.

Electrophysiological correlates of visual backward masking in patients with major depressive disorder

Depression and schizophrenia are two psychiatric diseases with high co-morbidity. For this reason, it is important to find sensitive endophenotypes, which may disentangle the two disorders. The Shine-Through paradigm, a visual backward masking task, is a potential endophenotype for schizophrenia. Masking is strongly deteriorated in schizophrenia patients, which is reflected in reduced EEG amplitudes. Here, we tested whether masking deficits and associated EEG changes are also found in patients with major depressive disorder. First, we replicated previous findings showing that depressive patients exhibit, at most, only weak masking deficits. Second, we found that the EEG amplitudes of depressive patients were reduced compared to controls and slightly increased compared to schizophrenia patients. As a secondary analysis, we compared the performance in the masking paradigm with three cognitive tasks, namely: the Wisconsin card sorting test, a verbal fluency test and a degraded continuous performance test. Performance in all but the verbal fluency test could discriminate schizophrenia from depression.

Schizophrenia patients using atypical medication perform better in visual tasks than patients using typical medication

Schizophrenia (SCZ) patients show deficits in many domains, including cognition and perception. However, results are often mixed. One reason for mixed results may be differences in medication. Very little is known about the role of medication in visual processing. Here, we investigated the effects of typical vs. atypical medication on contrast sensitivity (spatial frequencies ranging from 0.2 to 20 cycles per degree), vernier acuity, and visual backward masking. From a large pool of patients, we selected 50 patients (Study 1, conducted in Brazil) and 97 patients (Study 2, conducted in Georgia) taking either only typical or atypical medication. Patients with atypical medication performed significantly better than patients with typical medication for contrast sensitivity, vernier duration, and backward masking. As a secondary result, we found similar, but not significant, trends for the cognitive tasks (Stroop, Flanker, Trail-Making Test-B, Wisconsin Card Sorting Test and Continuous Performance Test) in the same patients. No correlations were found between demographics, psychopathology, chlorpromazine equivalents and visual processing. A conclusion of our study is that one needs to be careful comparing studies when medication is not comparable.

Electrophysiological correlates of visual backward masking in patients with first episode psychosis

Visual backward masking is strongly impaired in patients with schizophrenia. Masking deficits have been proposed as potential endophenotypes of schizophrenia. Masking performance deficits manifest as strongly reduced amplitudes in the electroencephalogram (EEG). In order to fulfill the criteria of an endophenotype, masking deficits should not vary substantially across time and should be present at the first psychotic event. To verify whether these conditions are met for visual backward masking, we tested patients with first episode psychosis (n = 21) in a longitudinal study. Patients were tested with visual backward masking and EEG three times every six months over a period of one year. We found that the EEG amplitudes of patients with first episode psychosis were higher as compared to those of patients with schizophrenia but lower as compared to those of unaffected controls. More interestingly, we found that the EEG amplitudes of patients with first episode psychosis remained stable over the course of one year. Since chronic schizophrenia patients have strongly reduced amplitudes, we speculate that the neural correlates of masking deficits (EEG amplitudes) continue to decrease as the disease progresses.

Neurophysiological Measures of the Perception of Antismoking Public Service Announcements Among Young Population

Tobacco constitutes a global emergency with totally preventable millions of deaths per year and smoking-related illnesses. Public service announcements (PSAs) are the main tool against smoking and by now their efficacy is still assessed through questionnaires and metrics, only months after their circulation. The present study focused on the young population, because at higher risk of developing tobacco addiction, investigating the reaction to the vision of Effective, Ineffective and Awarded antismoking PSAs through: electroencephalography (EEG), autonomic activity variation (Galvanic skin response—GSR- and Heart Rate—HR-) and Eye-Tracking (ET). The employed indices were: the EEG frontal alpha band asymmetry and the frontal theta; the Emotional Index (EI), deriving from the GSR and HR signals matching; the ET Visual Attention (VA) index, based on the ratio between the total time spent fixating an area of interest (AOI) and its area. Smokers expressed higher frontal alpha asymmetry values in comparison to non-smokers. Concerning frontal theta, Awarded PSAs reported the highest values in comparison to both Effective and Ineffective PSAs. EI results highlighted that lowest values were expressed by Heavy Smokers (HS), and Effective PSAs obtained the highest EI values. Finally, concerning the Effective PSAs, regression analysis highlighted a correlation between the number of cigarettes smoked by participants (independent variable) and frontal alpha asymmetry, frontal theta and EI values. ET results suggested that for the Ineffective PSAs the main focus were texts, while for the Effective and Awarded PSAs were the visual elements. Results support the use of methods aimed at assessing the physiological reaction for the evaluation of PSAs images, in particular when considering the smoking habits of target populations.