Relationship between function and structure in the visual cortex in healthy individuals and in patients with severe mental disorders

Patients with schizophrenia spectrum disorders (SCZspect) and bipolar disorders (BD) show impaired function in the primary visual cortex (V1), indicated by altered visual evoked potential (VEP). While the neural substrate for altered VEP in these patients remains elusive, altered V1 structure may play a role. One previous study found a positive relationship between the amplitude of the P100 component of the VEP and V1 surface area, but not V1 thickness, in a small sample of healthy individuals. Here, we aimed to replicate these findings in a larger healthy control (HC) sample (n = 307) and to examine the same relationship in patients with SCZspect (n = 30) or BD (n = 45). We also compared the mean P100 amplitude, V1 surface area and V1 thickness between controls and patients and found no significant group differences. In HC only, we found a significant positive P100-V1 surface area association, while there were no significant P100-V1 thickness relationships in HC, SCZspect or BD. Together, our results confirm previous findings of a positive P100-V1 surface area association in HC, whereas larger patient samples are needed to further clarify the function-structure relationship in V1 in SCZspect and BD.Relationship between function and structure in the visual cortex in healthy individuals and in patients with severe mental disorderspublishedVersio

Auditory Cortex Thickness Is Associated With N100 Amplitude in Schizophrenia Spectrum Disorders

Background and Hypothesis: The auditory cortex (AC) may play a central role in the pathophysiology of schizophrenia and auditory hallucinations (AH). Previous schizophrenia studies report thinner AC and impaired AC function, as indicated by decreased N100 amplitude of the auditory evoked potential. However, whether these structural and functional alterations link to AH in schizophrenia remain poorly understood. Study Design: Patients with a schizophrenia spectrum disorder (SCZspect), including patients with a lifetime experience of AH (AH+), without (AH−), and healthy controls underwent magnetic resonance imaging (39 SCZ spect, 22 AH+, 17 AH−, and 146 HC) and electroencephalography (33 SCZ spect, 17 AH+, 16 AH−, and 144 HC). Cortical thickness of the primary (AC1, Heschl’s gyrus) and secondary (AC2, Heschl’s sulcus, and the planum temporale) AC was compared between SCZ spect and controls and between AH+, AH−, and controls. To examine if the association between AC thickness and N100 amplitude differed between groups, we used regression models with interaction terms. Study Results: N100 amplitude was nominally smaller in SCZ spect (P = .03, d = 0.42) and in AH− (P = .020, d = 0.61), while AC2 was nominally thinner in AH+ (P = .02, d = 0.53) compared with controls. AC1 thickness was positively associated with N100 amplitude in SCZspect (t = 2.56, P = .016) and AH− (t= 3.18, P = .008), while AC2 thickness was positively associated with N100 amplitude in SCZspect (t = 2.37, P = .024) and in AH+ (t = 2.68, P = .019). Conclusions: The novel indings of positive associations between AC thickness and N100 amplitude in SCZ spect, suggest that a common neural substrate may underlie AC thickness and N100 amplitude alterations.publishedVersio

The relationship between central and peripheral oxytocin concentrations: a systematic review and meta-analysis protocol

Background Research examining the effects of oxytocin (OT) interventions on psychiatric, social-behavioral, and social-cognitive outcomes regularly collect peripheral levels of OT as markers of central bioavailability. Such inferences rest on the assumption that central and peripheral levels of OT are directly associated. However, conflicting evidence from coordinated sampling of central and peripheral OT question the validity of this assumption. The purpose of this meta-analysis is to evaluate the correlation between central and peripheral OT, as well as to account for potential heterogeneity in the literature. Methods/design Studies that report coordinated sampling of central and peripheral OT in humans and animals will be identified. Research investigating concentrations in both basal states and after exogenous administration will be considered. PubMed and Embase databases will be searched, along with citation lists of retrieved articles. Peer-reviewed studies written in English published from 1971 onwards will be included in the meta-analysis. Data will be extracted from eligible studies for a random-effects meta-analysis. For each study, a summary effect size, heterogeneity, risk of bias, publication bias, and the effect of categorical and continuous moderator variables will be determined. Discussion This systematic review and meta-analysis will identify and synthesize evidence to determine if there is an association between central and peripheral OT concentrations. If significant associations are observed, evidence would provide a rationale for future research to use peripheral measures as a proxy for central OT concentrations. Systematic review registration PROSPERO CRD4201502786

The correlation between central and peripheral oxytocin concentrations: a systematic review and meta-analysis

Data and analysis script. The 'cpot' csv file is the raw effect size data. The 'fdata' csv file includes data to recreate figures. The protocol for the systematic review is also include

The correlation between central and peripheral oxytocin concentrations: a systematic review and meta-analysis

Data and analysis script. The 'cpot' csv file is the raw effect size data. The 'fdata' csv file includes data to recreate figures. The protocol for the systematic review is also include

Immigration to Italy in the years 2005 - 2009 and the role of the EU: A View of Italian political parties

The thesis inquires into the stances of italian political parties towards the issue of immigration in the years 2005 - 2009 with a particular concern for the role of the EU in this policy area. Using a theoretical clasification of Zincone the thesis analyses parties' documents, electoral programmes and newspaper articles in order to identify the main issues and approaches adopted by the italian parties during the selected time period. The thesis proves to some measure the hypothesis that right- wing parties adopt mainly functionalist, legalitarian and identitarian approaches to immigration, whilst left-wing parties adopt solidarist, human-rights based and multiculturalist approach. In the run of the selected time period there was an increasement in the security rhetorics even by left-wing parties, so a political competition for ownership of the security issue was observed. Also a hypothesis was partially proved that left-wing parties want the EU migration and asylum policy to have a wide impact, whilst the right-wing parties want mainly the EU to help the member-state with the fight against illegal immigration and with negotiating readmission agreements

Indirect genetic effects of siblings

Within-family designs are increasingly used to decompose genotype-trait associations into direct and indirect genetic effects. Many such designs, including trio designs or within-sibship designs, assume an absence of sibling indirect genetic effects. Here, we expand two well-known molecular genetic within-family designs, one variance component (genome-based restricted maximum likelihood) and one trait-based (structural equation modeling with polygenic indices) to estimate sibling indirect genetic effects along with direct genetic effects. We link the Norwegian mother, father, and child cohort study (MoBa) to Norway’s national education database to model genetic effects on national standardized testing results at ages 10, 13, and 14, and on parent-rated ADHD symptoms at ages 3 and 8, in up to 15,971 genotyped and phenotyped siblings. Results from the genome-based restricted maximum likelihood and the structural equation modeling with polygenic indices approaches converge, albeit with the variance component estimates of genetic effects typically an order of magnitude greater than the trait-based estimates. We observe no indirect genetic effects of siblings on educational performance at any age, and only slightly negative indirect genetic effects of siblings on ADHD symptoms at age 3. We argue that the latter effect might reflect parental contrasted rating. The results suggest that within-family models of educational performance are unlikely to be drastically biased by an assumption of absent sibling indirect genetic effects. Combining trait-based analyses with variance component analyses can benefit understanding of indirect genetic effects, especially when the effects are not specific to a particular mechanism

The correlation between central and peripheral oxytocin concentrations: a systematic review and meta-analysis

AbstractThere is growing interest in the role of the oxytocin system in social cognition and behavior. Peripheral oxytocin concentrations are regularly used to approximate central concentrations in psychiatric research. This methodological approach has obvious appeal given the invasiveness of cerebrospinal fluid collection. However, the validity of this approach and potential moderators of the association between central and peripheral levels are unclear. Thus, we conducted a pre-registered systematic search and meta-analysis of correlations between central and peripheral oxytocin concentrations. A search of databases yielded 17 eligible studies for effect size synthesis and moderator analysis, resulting in a total sample size of 516 participants and subjects. Overall, a positive association between central and peripheral oxytocin concentrations was revealed [r=0.29, 95% CI (0.15, 0.42), p&lt;0.0001], along with a moderate-to-high level of heterogeneity across effect sizes [Q=88.14, p&lt;0.0001], and no evidence of publication bias (p=0.45). This association was significantly moderated by experimental context [Qb(4), p=0.0016]. The strongest association was observed after intranasal oxytocin administration (r=0.67, p&lt;.0001), a correlation that was significantly greater (p=.0002) than the equivalent association under baseline conditions (r=0.08, p=.31). These results support the use of peripheral levels of oxytocin as a marker of central levels, but only after exogenous oxytocin administration. Despite the popularity of using peripheral OT levels to approximate central levels during baseline conditions, this approach is not supported by the present results.</jats:p