There is evidence that in schizophrenia, imbalances in inflammatory and oxidative processes occur during pregnancy and in the early postnatal period, generating interest in the potential therapeutic efficacy of anti-inflammatory and antioxidant compounds. Mangiferin is a polyphenolic compound abundant in the leaves of Mangifera indica L. that has robust antioxidant and anti-inflammatory properties, making it a potential candidate for preventive or co-adjuvant therapy in schizophrenia. Hence, this study set-out to evaluate the effect of mango leaf extract (MLE) in a model of schizophrenia based on maternal immune activation, in which Poly I:C (4 mg/kg) is administered intravenously to pregnant rats. Young adult (postnatal day 60–70) or adolescent (postnatal day 35–49) male offspring received MLE (50 mg/kg of mangiferin) daily, and the effects of MLE in adolescence were compared to those of risperidone, assessing behavior, brain magnetic resonance imaging (MRI), and oxidative/inflammatory and antioxidant mediators in the adult offspring. MLE treatment in adulthood reversed the deficit in prepulse inhibition (PPI) but it failed to attenuate the sensitivity to amphetamine and the deficit in novel object recognition (NOR) induced. By contrast, adolescent MLE treatment prevented the sensorimotor gating deficit in the PPI test, producing an effect similar to that of risperidone. This MLE treatment also produced a reduction in grooming behavior, but it had no effect on anxiety or novel object recognition memory. MRI studies revealed that adolescent MLE administration partially counteracted the cortical shrinkage, and cerebellum and ventricle enlargement. In addition, MLE administration in adolescence reduced iNOS mediated inflammatory activation and it promoted the expression of biomarkers of compensatory antioxidant activity in the prefrontal cortex and hippocampus, as witnessed through the reduction of Keap1 and the accumulation of NRF2 and HO1. Together, these findings suggest that MLE might be an alternative therapeutic or preventive add-on strategy to improve the clinical expression of schizophrenia in adulthood, while also modifying the time course of this disease at earlier stages in populations at high-risk.

Prenatal exposure to maternal immune activation (MIA) and chronic adolescent cannabis use have both been identified as environmental risk factors for neuropsychiatric disorders. However, most individuals exposed to a single risk factor do not typically develop major mental illness, which suggests that multiple exposures may be required for illness onset. Here, we examine whether combined exposure to prenatal MIA and adolescent delta-9-tetrahydrocannabinol (THC), the main psychoactive component of cannabis, lead to enduring neuroanatomical and behavioural changes in adult offspring, potentially reflecting changes in humans indicative of mental illness.

Mice were prenatally exposed to a viral mimetic, poly I:C (5mg/kg), or vehicle at gestational day (GD)9, and then postnatally exposed to chronic THC (5mg/kg) or vehicle by intraperitoneal injections during adolescent development (postnatal day [PND]28-45). Longitudinal in vivo whole-brain magnetic resonance imaging (MRI) was performed pre-treatment, PND25, post-treatment, PND50, and in adulthood, PND85, followed by a series of behavioural tests aimed at assessing anxiety-like and locomotor, social, and sensorimotor gating behaviour. Post-mortem assessment of cannabinoid (CB)1 and 2 receptor expressing cells was performed in developmentally altered regions identified by MRI (anterior cingulate and somatosensory cortices, striatum, and hippocampus). We hypothesized that there would be differential, but synergistic effects of each exposure.

Briefly, we found subtle deviations in neurodevelopmental trajectory and subthreshold anxiety-like behaviours were observed in mice exposed to both risk factors. Sex-dependent effects were observed in patterns of shared brain-behaviour covariation, suggesting that exposure to MIA and THC may affect males and females in different ways. Density of CB1 and CB2 receptor positive cells was significantly decreased in all regions assessed for all mice exposed to either one or both risk factors, relative to controls.

These findings suggest that there may be a cumulative effect of risk factor exposure on gross neuroanatomical and behavioural development, and that the endocannabinoid system may be sensitive to both prenatal MIA, adolescent THC, or the combination. For full details, see our publication: .

In this dataset, you will find a total of 243 preprocessed structural MRIs (in MINC format) acquired at postnatal day ~25, ~50, and ~85 in mice exposed to poly I:C or vehicle control (0.9% sterile saline) at GD9, and then postnatally treated with vehicle or THC from PND 28-45. These are T1-weighted structural images at 100 micron isotropic resolution acquired on a 7 Tesla Bruker Biospec 70/30; matrix size of 180 x 160 x 90; 14.5 minutes, 20 degrees and TE/TR of 4.5/20 ms (2 averages, ~14 minutes). Anesthesia was induced with 3% isoflurane in oxygen and a (0.075 mg/kg bolus) dexmedetomidine injection. Anesthesia was maintained during the scan between 1.5-0.5% isoflurane, and a constant infusion of dexmedetomidine (0.05mg/kg/h continuous mg/kg during scan). T1-weighted scans were preprocessed by stripping native coordinates, flipping left-right to maintain fidelity, denoising, correcting inhomogeneities in the bias field using the N4 algorithm, and registering in LSQ6 alignment (i.e. 6 degrees of freedom are allowed for imagine alignment: translations and rotations along x, y, and z dimensions). The demographics information for each animal is included in the demographics.csv file.

Behavioural tests were performed following the postnatal day 85 scans in all animals with a 2 day rest period. These include: open field test, three chambered social approach, and prepulse inhibition. The data for all of these tests is presented in its own individual .csv spreadsheet.

Included in this data set are the structural MRIs in MINC format, the behavioural .csv data, and a readme.txt file providing further detail on the data structure and content, and on how to interpret the data column titles. DICOMS are also available for the structural MRI data, as are the raw (not-preprocessed) MINC files, available upon request to the authors.

Finally, the authors would like to acknowledge the funding bodies that supported the completion of this work including the Canadian Institute for Health Research, the Fonds de Recherche du Québec en Santé, and the Healthy Brains for Healthy Lives at McGill University.

Prenatal maternal immune activation (MIA) is a risk factor for neurodevelopmental disorders. How the gestational timing of MIA-exposure differentially impacts downstream development remains unclear. The data presented here includes longitudinal structural magnetic resonance imaging (MRI) data from weaning to adulthood, and behavioural testing in adolescence and adulthood on C57BL/6 mice exposed to MIA induced by the viral mimetic, polyinosinic:polycytidylic acid (poly I:C) either early (gestational day [GD]9) or late (GD17) in gestation.

The data published here was collected and analyzed for the following publication, where more details can be found (Guma et al., 2021 https://doi.org/10.1016/j.biopsych.2021.03.017). Briefly, we found that early MIA-exposure was associated with accelerated brain volume increases in adolescence/early-adulthood that normalized in later adulthood, in regions including the striatum, hippocampus, and cingulate cortex. Similarly, alterations in anxiety-like, stereotypic, and sensorimotor gating behaviours observed in adolescence normalized in adulthood. In contrast, MIA-exposure in late gestation had less impact on anatomical and behavioural profiles.

In addition to the univariate analyses described above, we also undertook a multivariate analysis (partial least squares) to relate imaging and behavioural variables for the time of greatest alteration, i.e. adolescence/early adulthood. We further explored the molecular underpinnings of region-specific alterations in early MIA-exposed mice in adolescence using RNA sequencing (data for differentially expressed genes in the anterior cingulate cortex, dorsal hippocampus, and ventral hippocampus are available via the original publication https://doi.org/10.1016/j.biopsych.2021.03.017 for a separate cohort of adolescent mice prenatally exposed to MIA or vehicle at GD9).

In this dataset, you will find a total of 376 preprocessed structural MRIs (in MINC format) acquired at postnatal day ~21, ~38, ~60, and ~90 in mice exposed to poly I:C or vehicle control (0.9% sterile saline) at GD9 or 17. These are T1-weighted, manganese enhanced (50mg/kg 24 hours pre-scan), structural images at 100 micron isotropic resolution acquired on a 7 Tesla Bruker Biospec 70/30; matrix size of 180 x 160 x 90; 14.5 minutes, 2 averages, using 5% isoflurane for induction, 1.5% for maintenance of anesthesia during the scan. T1-weighted scans were preprocessed by stripping native coordinates, flipping left-right to maintain fidelity, denoising, correcting inhomogeneities in the bias field using the N4 algorithm, and registering in LSQ6 alignment (i.e. 6 degrees of freedom are allowed for imagine alignment: translations and rotations along x, y, and z dimensions). The demographics information for each animal is included in the demographics.csv file.

Behavioural tests were performed following the postnatal day 38 and 90 scans in all animals with a 2 day rest period. These include: open field test, marble burying test, three chambered social approach, and prepulse inhibition. The attentional set shifting task was also performed following the final behavioural test in the postnatal day 90 wave of behaviours. The data for all of these tests is presented in its own individual .csv spreadsheet and includes data for both the timepoints evaluated.

Included in this data set are the structural MRIs in MINC format, the behavioural .csv data, and a readme.txt file providing further detail on the data structure and content, and on how to interpret the data column titles. DICOMS are also available for the structural MRI data, as are the raw (not-preprocessed) MINC files, available upon request to the authors.

Finally, the authors would like to acknowledge the funding bodies that supported the completion of this work including the Canadian Institute for Health Research, the Fonds de Recherche du Québec en Santé, and the Healthy Brains for Healthy Lives at McGill University.

Evidence from imaging studies suggests that the human brain has a small-world network topology that might be disrupted in certain brain disorders. However, current methodology is based on global graph theory measures, such as clustering, C, characteristic path length, L, and small-worldness, S, that lack spatial specificity and are insufficient to identify regional brain abnormalities. Here we propose novel ultra-fast methodology for mapping local properties of brain network topology such as local C, L and S (lC, lL and lS) in the human brain at 3-mm isotropic resolution from ‘resting-state’ magnetic resonance imaging data. Test-retest datasets from 40 healthy children/adolescents were used to demonstrate the overall good reliability of the measures across sessions and computational parameters (intraclass correlation > 0.5 for lC and lL) and their low variability across subjects (< 29%). Whereas regions with high local functional connectivity density (lFCD; local degree) in posterior parietal and occipital cortices demonstrated high lC and short lL, subcortical regions (globus pallidus, thalamus, hippocampus and amygdala), cerebellum (lobes and vermis), cingulum and temporal cortex also had high, lS, demonstrating stronger small-world topology than other hubs. Children/adolescents had stronger lFCD, higher lC and longer lL in most cortical regions and thalamus than 74 healthy adults, consistent with pruning of functional connectivity during maturation. In contrast, lFCD, lC and lL were weaker in thalamus and midbrain, and lL was shorter in frontal cortical regions and cerebellum for 69 schizophrenia patients than for 74 healthy controls, suggesting exaggerated pruning of connectivity in schizophrenia. Follow up correlation analyses for seeds in thalamus and midbrain uncovered lower positive connectivity of these regions in thalamus, putamen, cerebellum and frontal cortex (cingulum, orbitofrontal, inferior frontal) and lower negative connectivity in auditory, visual, motor, premotor and somatosensory cortices for schizophrenia patients than for controls, consistent with prior findings of thalamic disconnection in schizophrenia.

Children, adolescents, and young adults with at least one first-degree relative [familial high-risk (FHR)] with either schizophrenia (SZ) or bipolar disorder (BD) have a one-in-two risk of developing a psychiatric disorder. Here, we review functional magnetic resonance imaging (fMRI) studies which examined task-related brain activity in young individuals with FHR-SZ and FHR-BD. A systematic search identified all published task-related fMRI studies in children, adolescents, and young adults below an age of 27 years with a first-degree relative with SZ or BD, but without manifest psychotic or affective spectrum disorder themselves. The search identified 19 cross-sectional fMRI studies covering four main cognitive domains: 1) working memory (n = 3), 2) cognitive control (n = 4), 3) reward processing (n = 3), and 4) emotion processing (n = 9). Thirteen studies included FHR-BD, five studies included FHR-SZ, and one study included a pooled FHR group. In general, task performance did not differ between the respective FHR groups and healthy controls, but 18 out of the 19 fMRI studies revealed regional alterations in task-related activation. Brain regions showing group differences in peak activation were regions associated with the respective task domain and showed little overlap between FHR-SZ and FHR-BD. The low number of studies, together with the low number of subjects, and the substantial heterogeneity of employed methodological approaches within the domain of working memory, cognitive control, and reward processing impedes finite conclusions. Emotion processing was the most investigated task domain in FHR-BD. Four studies reported differences in activation of the amygdala, and two studies reported differences in activation of inferior frontal/middle gyrus. Together, these studies provide evidence for altered brain processing of emotions in children, adolescents, and young adults at FHR-BD. More studies of higher homogeneity, larger sample sizes and with a longitudinal study design are warranted to prove a shared or specific FHR-related endophenotypic brain activation in young first-degree relatives of individuals with SZ or BD, as well as to pinpoint specific alterations in brain activation during cognitive-, emotional-, and reward-related tasks.

Volumetric comparisons of ROIs in the left insula-TPJ between control (C; n = 45), adolescent-onset psychosis (E; n = 13) and adult-onset psychosis (A; n = 29) groups corrected for intracranial volume, gender and age. GMV, gray matter volume; ns, not significant; SD, standard deviation; WMV, white matter volume.Volumetric differences between control, adolescent-onset psychosis, adult-onset psychosis groups.

Evidence shows that there are reductions in gray matter volume (GMV) and changes in long association white matter fibres within the left insula-temporoparietal junction (TPJ) during the early stages of psychotic disorders but less is known about short association fibres (sAFs). In this study we sought to characterise the changes in sAFs and associated volumetric changes of the left insula-TPJ during the early stages of psychosis. Magnetic resonance imaging was obtained from a sample of young people with psychosis (n = 42) and healthy controls (n = 45), and cortical parcellations of the left insula-TPJ were used as seeding masks to reconstruct 13 sAFs. Compared to healthy counterparts, the psychosis group showed significant reductions in fractional anisotropy (FA) in the sAFs connecting the superior (STG) and middle temporal gyri (MTG) and as well as reduced GMV within the inferior temporal gyrus and increased white matter volume (WMV) within Heschl's gyrus (HG). Furthermore, adolescent-onset psychosis subjects (onset 18 year or earlier) showed FA reductions in the STG-HG sAF when compared to adult-onset subjects, but this was not associated with changes in GMV nor WMV of the STG or HG. These findings suggest that during the early stages of psychosis, changes in sAFs and associated cortical GMV and WMV appear to occur independently, however age of onset of a psychotic syndrome/disorder influences the pattern of neuroanatomical abnormalities.