New-Onset Psychosis Associated With a Lesion Localized in the Rostral Tectum: Insights Into Pathway-Specific Connectivity Disrupted in Psychosis

Altered cerebellar effective connectivity in first-episode schizophrenia and long-term changes after treatment

AIM

Cerebello-cortical functional dysconnectivity plays a key role in the pathology of schizophrenia (SZ). We aimed to investigate the changes in cerebello-cortical directional connectivity in patients with SZ.

METHODS

A total of 180 drug-naïve patients with first-episode SZ (54 reassessed after 1 year of treatment) and 166 healthy controls (HCs) were included. Resting-state functional magnetic resonance imaging was used to perform Granger causal analysis, in which each of the nine cerebellar functional systems was defined as a seed. The observed effective connectivity (EC) alterations at baseline were further assessed at follow-up and were associated with changes in psychotic symptom.

RESULTS

We observed increased bottom-up EC in first-episode SZ from the cerebellum to the cerebrum (e.g. from the cerebellar attention and cingulo-opercular systems to the bilateral angular gyri, and from the cerebellar cingulo-opercular system to the right inferior frontal gyrus). In contrast, decreased top-down EC in the first-episode SZ was mainly from the cerebrum to the cerebellum (e.g. from the right inferior temporal gyrus, left middle temporal gyrus, left putamen, and right angular gyrus to the cerebellar language system). After 1 year of antipsychotic treatment, information projections from the cerebrum to the cerebellum were partly restored and positively related to symptom remission.

CONCLUSION

These findings suggest that decreased top-down EC during the acute phase of SZ may be a state-dependent alteration related to symptoms and medication. However, increased bottom-up EC may reflect a persistent pathological trait.

Neurocysticercosis presenting as psychosis: A case report and a brief literature review

Patients with neurocysticercosis, a common infection of the central nervous system caused by Taenia solium, have been reported to develop neuropsychiatric complications. We report a unique case of recurrent psychosis caused by neurocysticercosis in a 37-year-old El Salvador immigrant woman and discuss the underlying pathophysiological mechanisms of the complications. We reviewed published case reports of neurocysticercosis that presented with psychotic features and compared their diagnostic evaluation, the underlying pathophysiology of complications and treatment regimen with our case. This review concludes that neurocysticercosis should be considered in the differential diagnosis of patients presenting with psychosis with a history of residence in an endemic area.

Early or Late Gestational Exposure to Maternal Immune Activation Alters Neurodevelopmental Trajectories in Mice: An Integrated Neuroimaging, Behavioral, and Transcriptional Study

BACKGROUND

Exposure to maternal immune activation (MIA) in utero is a risk factor for neurodevelopmental disorders later in life. The impact of the gestational timing of MIA exposure on downstream development remains unclear.

METHODS

We characterized neurodevelopmental trajectories of mice exposed to the viral mimetic poly I:C (polyinosinic:polycytidylic acid) either on gestational day 9 (early) or on day 17 (late) using longitudinal structural magnetic resonance imaging from weaning to adulthood. Using multivariate methods, we related neuroimaging and behavioral variables for the time of greatest alteration (adolescence/early adulthood) and identified regions for further investigation using RNA sequencing.

RESULTS

Early MIA exposure was associated with accelerated brain volume increases in adolescence/early adulthood that normalized in later adulthood in the striatum, hippocampus, and cingulate cortex. Similarly, alterations in anxiety-like, stereotypic, and sensorimotor gating behaviors observed in adolescence normalized in adulthood. MIA exposure in late gestation had less impact on anatomical and behavioral profiles. Multivariate maps associated anxiety-like, social, and sensorimotor gating deficits with volume of the dorsal and ventral hippocampus and anterior cingulate cortex, among others. The most transcriptional changes were observed in the dorsal hippocampus, with genes enriched for fibroblast growth factor regulation, autistic behaviors, inflammatory pathways, and microRNA regulation.

CONCLUSIONS

Leveraging an integrated hypothesis- and data-driven approach linking brain-behavior alterations to the transcriptome, we found that MIA timing differentially affects offspring development. Exposure in late gestation leads to subthreshold deficits, whereas exposure in early gestation perturbs brain development mechanisms implicated in neurodevelopmental disorders.

Combined lesion-deficit and fMRI approaches in single-case studies: Unique contributions to cognitive neuroscience

Although lesion-deficit case studies are foundational in cognitive neuroscience, published papers presenting single lesion cases are declining. In this review, we argue that there is a valuable place for single-case lesion-deficit research, especially when combined with functional neuroimaging methods, such as functional magnetic resonance imaging (fMRI). To support this, we present a summary of notable findings from single-case combined lesion-deficit and fMRI studies published in recent years (2017-2020). These studies show the unique value that this combined approach brings to the understanding of complex functions, brain-level connectivity, and plasticity and recovery. We encourage researchers to consider combining lesion-deficit and functional imaging methods in the analysis of single cases, as this approach affords unique opportunities to address challenging unanswered questions about brain-behavior relationships.

MicroRNA profiling of the pig periaqueductal grey (PAG) region reveals candidates potentially related to sex-dependent differences

Background

MicroRNAs indirectly orchestrate myriads of essential biological processes. A wide diversity of miRNAs of the neurodevelopmental importance characterizes the brain tissue, which, however, exhibits region-specific miRNA profile differences. One of the most conservative regions of the brain is periaqueductal grey (PAG) playing vital roles in significant functions of this organ, also those observed to be sex-influenced. The domestic pig is an important livestock species but is also believed to be an excellent human model. This is of particular importance for neurological research because of the similarity of pig and human brains as well as difficult access to human samples. However, the pig PAG profile has not been characterized so far. Moreover, molecular bases of sex differences connected with brain functioning, including miRNA expression profiles, have not been fully deciphered yet.

Methods

Thus, in this study, we applied next-generation sequencing to characterize pig PAG expressed microRNAs. Furthermore, we performed differential expression analysis between females and males to identify changes of the miRNA profile and reveal candidates underlying sex-related differences.

Results

As a result, known brain-enriched, and new miRNAs which will expand the available profile, were identified. The downstream analysis revealed 38 miRNAs being differentially expressed (DE) between female and male samples. Subsequent pathway analysis showed that they enrich processes vital for neuron growth and functioning, such as long-term depression and axon guidance. Among the identified sex-influenced miRNAs were also those associated with the PAG physiology and diseases related to this region.

Conclusions

The obtained results broaden the knowledge on the porcine PAG miRNAome, along with its dynamism reflected in different isomiR signatures. Moreover, they indicate possible mechanisms associated with sex-influenced differences mediated via miRNAs in the PAG functioning. They also provide candidate miRNAs for further research concerning, i.e., sex-related bases of physiological and pathological processes occurring in the nervous system.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-020-00343-2.