Subcortical brain volumes relate to neurocognition in schizophrenia and bipolar disorder and healthy controls

Association of P50 with social function, but not with cognition in patients with first-episode schizophrenia

Functional deficits including cognitive impairment and social dysfunction are the core symptoms of schizophrenia (SCZ), and sensory gating (SG) deficits may be involved in the pathological mechanism of functional deficits in SCZ. This study was to investigate the relationship between defective P50 inhibition and functional deficits in first-episode drug naïve (FEDN) SCZ patients. A total of 95 FEDN SCZ patients and 53 healthy controls (HC) were recruited. The Chinese version of UCSD Performance-Based Skills (UPSA), MATRICS Consensus Cognitive Battery (MCCB), and EEG system were used to assess the social function, cognitive performance, and P50 inhibition, respectively. The MCCB total score and eight domain scores were significantly lower in patients with FEDN SCZ than those in HC (all p < 0.05). The UPSA total score and financial skills scores were also significantly lower in SCZ patients than that in the HC (all p < 0.05). Compared with HC, patients with FEDF SCZ had a higher P50 ratio (all p < 0.05). There was no correlation between P50 components and MCCB scores in patients with FEDF SCZ. However, there was only a correlation between the P50 ratio and UPSA financial skills, communication skills, or total score in patients (all p < 0.05). Defective P50 inhibition in FEDN SCZ patients may be associated with social dysfunction but not cognitive impairment, suggesting that the social dysfunction and cognitive impairment of patients with FEDN SCZ may have different pathogenic mechanisms.

Structural and functional disruption of subcortical limbic structures related with executive function in pediatric bipolar disorder

BACKGROUND

Impaired cognition has been demonstrated in pediatric bipolar disorder (PBD). The subcortical limbic structures play a key role in PBD. However, alternations of anatomical and functional characteristics of subcortical limbic structures and their relationship with neurocognition of PBD remain unclear.

METHODS

Thirty-six PBD type I (PBD-I) (15.36 ± 0.32 years old), twenty PBD type II (PBD-II) (14.80 ± 0.32 years old) and nineteen age-gender matched healthy controls (HCs) (14.16 ± 0.36 years old) were enlisted. Primarily, the volumes of the subcortical limbic structures were obtained and differences in the volumes were evaluated. Then, these structures served as seeds of regions of interest to calculate the voxel-wised functional connectivity (FC). After that, correlation analysis was completed between volumes and FC of brain regions showing significant differences and neuropsychological tests.

RESULTS

Compared to HCs, both PBD-I and PBD-II patients showed a decrease in the Stroop color word test (SCWT) and digit span backward test scores. Compared with HCs, PBD-II patients exhibited a significantly increased volume of right septal nuclei, and PBD-I patients presented increased FC of right nucleus accumbens and bilateral pallidum, of right basal forebrain with right putamen and left pallidum. Both the significantly altered volumes and FC were negatively correlated with SCWT scores.

SIGNIFICANCE

The study revealed the role of subcortical limbic structural and functional abnormalities on cognitive impairments in PBD patients. These may have far-reaching significance for the etiology of PBD and provide neuroimaging clues for the differential diagnosis of PBD subtypes.

CONCLUSIONS

Distinctive features of neural structure and function in PBD subtypes may contribute to better comprehending the potential mechanisms of PBD.

Focused Ultrasound Stimulates the Prefrontal Cortex and Prevents MK-801-Induced Psychiatric Symptoms of Schizophrenia in Rats

BACKGROUND AND HYPOTHESIS

Treatment of schizophrenia remains a major challenge. Recent studies have focused on glutamatergic signaling hypoactivity through N-methyl-D-aspartate (NMDA) receptors. Low-intensity pulsed ultrasound (LIPUS) improves behavioral deficits and ameliorates neuropathology in dizocilpine (MK-801)-treated rats. The aim of this study was to investigate the efficacy of LIPUS against psychiatric symptoms and anxiety-like behaviors.

STUDY DESIGN

Rats assigned to 4 groups were pretreated with or without LIPUS for 5 days. The open field and prepulse inhibition tests were performed after saline or MK-801 (0.3 mg/kg) administration. Then, the neuroprotective effects of LIPUS on the MK-801-treated rats were evaluated using western blotting and immunohistochemical staining.

STUDY RESULTS

LIPUS stimulation of the prefrontal cortex (PFC) prevented deficits in locomotor activity and sensorimotor gating and improved anxiety-like behavior. MK-801 downregulated the expression of NR1, the NMDA receptor, in rat medial PFC (mPFC). NR1 expression was significantly higher in animals receiving LIPUS pretreatment compared to those receiving only MK-801. In contrast, a significant increase in c-Fos-positive cells in the mPFC and ventral tegmental area was observed in the MK-801-treated rats compared to those receiving only saline; this change was suppressed by pretreatment with LIPUS.

CONCLUSIONS

This study provides new evidence for the role of LIPUS stimulation in regulating the NMDA receptor and modulating c-Fos activity, which makes it a potentially valuable antipsychotic treatment for schizophrenia.

Visual processing deficits in patients with schizophrenia spectrum and bipolar disorders and associations with psychotic symptoms, and intellectual abilities

Objective

Low-level sensory disruption is hypothesized as a precursor to clinical and cognitive symptoms in severe mental disorders. We compared visual discrimination performance in patients with schizophrenia spectrum disorder or bipolar disorder with healthy controls, and investigated associations with clinical symptoms and IQ.

Methods

Patients with schizophrenia spectrum disorder (n = 32), bipolar disorder (n = 55) and healthy controls (n = 152) completed a computerized visual discrimination task. Participants responded whether the latter of two consecutive grids had higher or lower spatial frequency, and discrimination thresholds were estimated using an adaptive maximum likelihood procedure. Case-control differences in threshold were assessed using linear regression, F-test and post-hoc pair-wise comparisons. Linear models were used to test for associations between visual discrimination threshold and psychotic symptoms derived from the PANSS and IQ assessed using the Matrix Reasoning and Vocabulary subtests from the Wechsler Abbreviated Scale of Intelligence (WASI).

Results

Robust regression revealed a significant main effect of diagnosis on discrimination threshold (robust F = 6.76, p = .001). Post-hoc comparisons revealed that patients with a schizophrenia spectrum disorder (mean = 14%, SD = 0.08) had higher thresholds compared to healthy controls (mean = 10.8%, SD = 0.07, β = 0.35, t = 3.4, p = .002), as did patients with bipolar disorder (12.23%, SD = 0.07, β = 0.21, t = 2.42, p = .04). There was no significant difference between bipolar disorder and schizophrenia (β = -0.14, t = -1.2, p = .45). Linear models revealed negative associations between IQ and threshold across all participants when controlling for diagnostic group (β = -0.3, t = -3.43, p = .0007). This association was found within healthy controls (t = -3.72, p = .0003) and patients with bipolar disorder (t = -2.53, p = .015), and no significant group by IQ interaction on threshold (F = 0.044, p = .97). There were no significant associations between PANSS domain scores and discrimination threshold.

Conclusion

Patients with schizophrenia spectrum or bipolar disorders exhibited higher visual discrimination thresholds than healthy controls, supporting early visual deficits among patients with severe mental illness. Discrimination threshold was negatively associated with IQ among healthy controls and bipolar disorder patients. These findings elucidate perception-related disease mechanisms in severe mental illness, which warrants replication in independent samples.

Theory of mind profile and cerebellar alterations in remitted bipolar disorder 1 and 2: a comparison study

The literature on social cognition abilities in bipolar disorder (BD) is controversial about the occurrence of theory of mind (ToM) alterations. In addition to other cerebral structures, such as the frontal and limbic areas, the processing of socially relevant stimuli has also been attributed to the cerebellum, which has been demonstrated to be involved in the above-mentioned disorder. Nevertheless, the cerebellar contribution to ToM deficits in bipolar patients needs to be elucidated further. To this aim, two tests assessing different components of ToM were used to evaluate the ability to appreciate affective and mental states of others in 17 individuals with a diagnosis of BD type 1 (BD1) and 13 with BD type 2 (BD2), both in the euthymic phase, compared to healthy matched controls. Cerebellar gray matter (GM) volumes were extracted and compared between BD1 and controls and BD2 and controls by using voxel-based morphometry. The results showed that BD1 patients were compromised in the cognitive and advanced components of ToM, while the BD2 ToM profile resulted in a more widespread compromise, also involving affective and automatic components. Both overlapping and differing areas of cerebellar GM reduction were found. The two groups of patients presented a pattern of GM reduction in cerebellar portions that are known to be involved in the affective and social domains, such as the vermis and Crus I and Crus II. Interestingly, in both BD1 and BD2, positive correlations were detected between lower ToM scores and decreased volumes in the cerebellum. Overall, BD2 patients showed a more compromised ToM profile and greater cerebellar impairment than BD1 patients. The different patterns of structural abnormalities may account for the different ToM performances evidenced, thus leading to divergent profiles between BD1 and BD2.

Subcortical Brain Morphometry Differences between Adults with Autism Spectrum Disorder and Schizophrenia

Autism spectrum disorder (ASD) and schizophrenia (SZ) are neuropsychiatric disorders that overlap in symptoms associated with social-cognitive impairment. Subcortical structures play a significant role in cognitive and social-emotional behaviors and their abnormalities are associated with neuropsychiatric conditions. This exploratory study utilized ABIDE II/COBRE MRI and corresponding phenotypic datasets to compare subcortical volumes of adults with ASD (n = 29), SZ (n = 51) and age and gender matched neurotypicals (NT). We examined the association between subcortical volumes and select behavioral measures to determine whether core symptomatology of disorders could be explained by subcortical association patterns. We observed volume differences in ASD (viz., left pallidum, left thalamus, left accumbens, right amygdala) but not in SZ compared to their respective NT controls, reflecting morphometric changes specific to one of the disorder groups. However, left hippocampus and amygdala volumes were implicated in both disorders. A disorder-specific negative correlation (r = −0.39, p = 0.038) was found between left-amygdala and scores on the Social Responsiveness Scale (SRS) Social-Cognition in ASD, and a positive association (r = 0.29, p = 0.039) between full scale IQ (FIQ) and right caudate in SZ. Significant correlations between behavior measures and subcortical volumes were observed in NT groups (ASD-NT range; r = −0.53 to −0.52, p = 0.002 to 0.004, SZ-NT range; r = −0.41 to −0.32, p = 0.007 to 0.021) that were non-significant in the disorder groups. The overlap of subcortical volumes implicated in ASD and SZ may reflect common neurological mechanisms. Furthermore, the difference in correlation patterns between disorder and NT groups may suggest dysfunctional connectivity with cascading effects unique to each disorder and a potential role for IQ in mediating behavior and brain circuits.

Cortical and Subcortical Structural Morphometric Profiles in Individuals with Nonaffective and Affective Early Illness Psychosis

Research has found strong evidence for common and distinct morphometric brain abnormality profiles in nonaffective psychosis (NAff-P) and affective psychosis (Aff-P). Due to chronicity and prolonged medication exposure confounds, it is crucial to examine structural morphometry early in the course of psychosis. Using Human Connectome Project-Early Psychosis data, multivariate profile analyses were implemented to examine regional profiles for cortical thickness, cortical surface area, subcortical volume, and ventricular volume in healthy control (HC; n = 56), early illness NAff-P (n = 83), and Aff-P (n = 30) groups after accounting for normal aging. Associations with symptom severity, functioning, and cognition were also examined. Group regional profiles were significantly nonparallel and differed in level for cortical thickness (P < .001), with NAff-P having widespread cortical thinning relative to HC and Aff-P and some regions showing greater deficits than others. Significant nonparallelism of group regional profiles was also evident for cortical surface area (P < .006), with Aff-P and N-Aff-P differing from HC and from each other (P < .001). For subcortical volume, there was significant profile nonparallelism with NAff-P having an enlarged left pallidum and smaller accumbens and hippocampus (P < .028), and Aff-P having a smaller accumbens and amygdala (P < .006), relative to HC. NAff-P also had larger basal ganglia compared to Aff-P. Furthermore, NAff-P had enlarged ventricles (P < .055) compared to HC and Aff-P. Additionally, greater ventricular volume was associated with increased manic symptoms in NAff-P and Aff-P. Overall, this study found common and distinct regional morphometric profile abnormalities in early illness NAff-P and Aff-P, providing evidence for both shared and disease-specific pathophysiological processes.

Wisket rat model of schizophrenia: Impaired motivation and, altered brain structure, but no anhedonia

It is well-known that the poor cognition in schizophrenia is strongly linked to negative symptoms, including motivational deficit, which due to, at least partially, anhedonia. The goal of this study was to explore whether the schizophrenia-like Wisket animals with impaired motivation (obtained in the reward-based hole-board test), also show decreased hedonic behavior (investigated with the sucrose preference test). While neurochemical alterations of different neurotransmitter systems have been detected in the Wisket rats, no research has been performed on structural changes. Therefore, our additional aim was to reveal potential neuroanatomical and structural alterations in different brain regions in these rats. The rats showed decreased general motor activity (locomotion, rearing and exploration) and impaired task performance in the hole-board test compared to the controls, whereas no significant difference was observed in the sucrose preference test between the groups. The Wisket rats exhibited a significant decrease in the frontal cortical thickness and the hippocampal area, and moderate increases in the lateral ventricles and cell disarray in the CA3 subfield of hippocampus. To our knowledge, this is the first study to investigate the hedonic behavior and neuroanatomical alterations in a multi-hit animal model of schizophrenia. The results obtained in the sucrose preference test suggest that anhedonic behavior might not be involved in the impaired motivation obtained in the hole-board test. The neuropathological changes agree with findings obtained in patients with schizophrenia, which refine the high face validity of the Wisket model.

The Association Between Lentiform Nucleus Function and Cognitive Impairments in Schizophrenia

Introduction: Cognitive decline is the core schizophrenia symptom, which is now well accepted. Holding a role in various aspects of cognition, lentiform nucleus (putamen and globus pallidus) dysfunction contributes to the psychopathology of this disease. However, the effects of lentiform nucleus function on cognitive impairments in schizophrenia are yet to be investigated.

Objectives: We aim to detect the fractional amplitude of low-frequency fluctuation (fALFF) alterations in patients with schizophrenia, and examine how their behavior correlates in relation to the cognitive impairments of the patients.

Methods: All participants underwent magnetic resonance imaging (MRI) and cognitive assessment (digit span and digit symbol coding tests). Screening of brain regions with significant changes in fALFF values was based on analysis of the whole brain. The data were analyzed between Jun 2020 and Mar 2021. There were no interventions beyond the routine therapy determined by their clinicians on the basis of standard clinical practice.

Results: There were 136 patients (75 men and 61 women, 24.1 ± 7.4 years old) and 146 healthy controls (82 men and 64 women, 24.2 ± 5.2 years old) involved in the experiments seriatim. Patients with schizophrenia exhibited decreased raw scores in cognitive tests (p < 0.001) and increased fALFF in the bilateral lentiform nuclei (left: 67 voxels; x = −24, y = −6, z = 3; peak t-value = 6.90; right: 16 voxels; x = 18, y = 0, z = 3; peak t-value = 6.36). The fALFF values in the bilateral lentiform nuclei were positively correlated with digit span-backward test scores (left: r = 0.193, p = 0.027; right: r = 0.190, p = 0.030), and the right lentiform nucleus was positively correlated with digit symbol coding scores (r = 0.209, p = 0.016).

Conclusion: This study demonstrates that cognitive impairments in schizophrenia are associated with lentiform nucleus function as revealed by MRI, involving working memory and processing speed.

Microinjection of Reelin into the mPFC prevents MK-801-induced recognition memory impairment in mice

Reelin, a large extracellular matrix protein, helps to regulate neuronal plasticity and cognitive function. Several studies have shown that Reelin dysfunction, resulting from factors such as mutations in gene RELN or low Reelin expression, is associated with schizophrenia (SCZ). We previously reported that microinjection of Reelin into cerebral ventricle prevents phencyclidine-induced cognitive and sensory-motor gating deficits. However, it remains unclear whether and how Reelin ameliorates behavioral abnormalities in the animal model of SCZ. In the present study, we evaluated the effect of recombinant Reelin microinjection into the medial prefrontal cortex (mPFC) on abnormal behaviors induced by MK-801, an N-methyl-D-aspartate receptor antagonist. Microinjection of Reelin into the mPFC prevented impairment of recognition memory of MK-801-treated mice in the novel object recognition test (NORT). On the other hand, the same treatment had no effect on deficits in sensory-motor gating and short-term memory in the pre-pulse inhibition and Y-maze tests, respectively. To establish the neural substrates that respond to Reelin, the number of c-Fos-positive cells in the mPFC was determined. A significant increase in c-Fos-positive cells in the mPFC of MK-801-treated mice was observed when compared with saline-treated mice, and this change was suppressed by microinjection of Reelin into the mPFC. A K2360/2467A Reelin that cannot bind to its receptor failed to ameliorate MK-801-induced cognitive deficits in NORT. These results suggest that Reelin prevents MK-801-induced recognition memory impairment by acting on its receptors to suppress neural activity in the mPFC of mice.

Association between body mass index and subcortical brain volumes in bipolar disorders-ENIGMA study in 2735 individuals

Individuals with bipolar disorders (BD) frequently suffer from obesity, which is often associated with neurostructural alterations. Yet, the effects of obesity on brain structure in BD are under-researched. We obtained MRI-derived brain subcortical volumes and body mass index (BMI) from 1134 BD and 1601 control individuals from 17 independent research sites within the ENIGMA-BD Working Group. We jointly modeled the effects of BD and BMI on subcortical volumes using mixed-effects modeling and tested for mediation of group differences by obesity using nonparametric bootstrapping. All models controlled for age, sex, hemisphere, total intracranial volume, and data collection site. Relative to controls, individuals with BD had significantly higher BMI, larger lateral ventricular volume, and smaller volumes of amygdala, hippocampus, pallidum, caudate, and thalamus. BMI was positively associated with ventricular and amygdala and negatively with pallidal volumes. When analyzed jointly, both BD and BMI remained associated with volumes of lateral ventricles  and amygdala. Adjusting for BMI decreased the BD vs control differences in ventricular volume. Specifically, 18.41% of the association between BD and ventricular volume was mediated by BMI (Z = 2.73, p = 0.006). BMI was associated with similar regional brain volumes as BD, including lateral ventricles, amygdala, and pallidum. Higher BMI may in part account for larger ventricles, one of the most replicated findings in BD. Comorbidity with obesity could explain why neurostructural alterations are more pronounced in some individuals with BD. Future prospective brain imaging studies should investigate whether obesity could be a modifiable risk factor for neuroprogression.

A Systematic Review of Cognition-Brain Morphology Relationships on the Schizophrenia-Bipolar Disorder Spectrum

The nature of the relationship between cognition and brain morphology in schizophrenia-spectrum disorders (SSD) and bipolar disorder (BD) is uncertain. This review aimed to address this, by providing a comprehensive systematic investigation of links between several cognitive domains and brain volume, cortical thickness, and cortical surface area in SSD and BD patients across early and established illness stages. An initial search of PubMed and Scopus databases resulted in 1486 articles, of which 124 met inclusion criteria and were reviewed in detail. The majority of studies focused on SSD, while those of BD were scarce. Replicated evidence for specific regions associated with indices of cognition was minimal, however for several cognitive domains, the frontal and temporal regions were broadly implicated across both recent-onset and established SSD, and to a lesser extent BD. Collectively, the findings of this review emphasize the significance of both frontal and temporal regions for some domains of cognition in SSD, while highlighting the need for future BD-related studies on this topic.

Brain morphology does not clearly map to cognition in individuals on the bipolar-schizophrenia-spectrum: a cross-diagnostic study of cognitive subgroups

BACKGROUND

Characterisation of brain morphological features common to cognitively similar individuals with bipolar disorder (BD) and schizophrenia spectrum disorders (SSD) may be key to understanding their shared neurobiological deficits. In the current study we examined whether three previously characterised cross-diagnostic cognitive subgroups differed among themselves and in comparison to healthy controls across measures of brain morphology.

METHOD

T1-weighted structural magnetic resonance imaging scans were obtained for 143 individuals; 65 healthy controls and 78 patients (SSD, n = 40; BD I, n = 38) classified into three cross-diagnostic cognitive subgroups: Globally Impaired (n = 24), Selectively Impaired (n = 32), and Superior/Near-Normal (n = 22). Cognitive subgroups were compared to each other and healthy controls on three separate analyses investigating (1) global, (2) regional, and (3) vertex-wise comparisons of brain volume, thickness, and surface area.

RESULTS

No significant subgroup differences were evident in global measures of brain morphology. In region of interest analyses, the Selectively Impaired subgroup had greater right accumbens volume than those Superior/Near-Normal subgroup and healthy controls, and the Superior/Near-Normal subgroup had reduced volume of the left entorhinal region compared to all other groups. In vertex-wise comparisons, the Globally Impaired subgroup had greater right precentral volume than the Selectively Impaired subgroup, and thicker cortex in the postcentral region relative to the Superior/Near-Normal subgroup.

LIMITATIONS

Exploration of medication effects was limited in our data.

CONCLUSIONS

Although some differences were evident in this sample, generally cross-diagnostic cognitive subgroups of individuals with SSD and BD did not appear to be clearly distinguished by patterns in brain morphology.

Subcortical Brain Volumes Relate to Neurocognition in First-Episode Schizophrenia, Bipolar Disorder, Major Depression Disorder, and Healthy Controls

OBJECTIVE

To explore differences and similarities in relationships between subcortical structure volumes and neurocognition among the four subject groups, including first-episode schizophrenia (FES), bipolar disorder (BD), major depression disorder (MDD), and healthy controls (HCs).

METHODS

We presented findings from subcortical volumes and neurocognitive analyses of 244 subjects (109 patients with FES; 63 patients with BD, 30 patients with MDD, and 42 HCs). Using the FreeSurfer software, volumes of 16 selected subcortical structures were automatically segmented and analyzed for relationships with results from seven neurocognitive tests from the MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) Cognitive Consensus Battery (MCCB).

RESULTS

Larger left lateral ventricle volumes in FES and BD, reduced bilateral hippocampus and amygdala volumes in FES, and lower bilateral amygdala volumes in BD and MDD were presented compared with HCs, and both FES and BD had a lower bilateral amygdala volume than MDD; there were seven cognitive dimension, five cognitive dimension, and two cognitive dimension impairments in FES, BD, and MDD, respectively; significant relationships were found between subcortical volumes and neurocognition in FES and BD but not in MDD and HCs; besides age and years of education, some subcortical volumes can predict neurocognitive performances variance.

CONCLUSION

The different degrees of subcortical volume lessening may contribute to the differences in cognitive impairment among the three psychiatric disorders.

Numerical density of oligodendrocytes and oligodendrocyte clusters in the anterior putamen in major psychiatric disorders

There is increasing evidence to support the notion that oligodendrocyte and myelin abnormalities may contribute to the functional dysconnectivity found in the major psychiatric disorders. The putamen, which is an important hub in the cortico-striato-thalamo-cortical loop, has been implicated in a broad spectrum of psychiatric illnesses and is a central target of their treatments. Previously we reported a reduction in the numerical density of oligodendrocytes and oligodendrocyte clusters in the prefrontal and parietal cortex in schizophrenia. Oligodendrocyte clusters contain oligodendrocyte progenitors and are involved in functionally dependent myelination. We measured the numerical density (Nv) of oligodendrocytes and oligodendrocyte clusters in the putamen in schizophrenia, bipolar disorder (BPD) and major depressive disorder (MDD) as compared to healthy controls (15 cases per group). Optical disector was used to estimate the Nv of oligodendrocytes and oligodendrocyte clusters. A significant reduction in both the Nv of oligodendrocytes (- 34%; p < 0.01) and the Nv of oligodendrocyte clusters (- 41%; p < 0.05) was found in the schizophrenia group as compared to the control group. Sexual dimorphism for both measurements was found only within the control group. The Nv of oligodendrocytes was significantly lower in male schizophrenia cases as compared to the male control cases. However, the Nv of oligodendrocyte clusters was significantly lower in all male clinical cases as compared to the male control group. The data suggest that lowered density of oligodendrocytes and oligodendrocyte clusters may contribute to the altered functional connectivity in the putamen in subjects with schizophrenia.

The association of serologically documented maternal thyroid conditions during pregnancy with bipolar disorder in offspring

OBJECTIVES

Higher rates of thyroid conditions are reported in individuals with bipolar disorder. However, no study to date has considered whether maternal thyroid conditions during pregnancy are associated with offspring risk of bipolar disorder, even though the fetus exclusively relies on maternal thyroid hormones through the early second trimester. We therefore examined the association between offspring bipolar disorder and serologically documented maternal thyroid conditions.

METHODS

The study was based on a nested case-control design that utilized data from the Child Health and Development Study, a birth cohort that enrolled pregnant women from 1959 to 1966. Eighty-five cases with DSM-IV-TR were ascertained and matched to controls (1:2) by date of birth, sex, gestational timing of the serum draws, and residence in Alameda County the first year receiving treatment. Archived prenatal maternal serum drawn during early to mid-gestation was used to measure two thyroid hormones, free thyroxine (fT4) and thyroid stimulating hormone (TSH). Subclinical and clinical hypothyroxinemia, hypothyroidism, and hyperthyroidism were determined based on standard methods.

RESULTS

Exposure to maternal hypothyroxinemia was associated with a five-fold increased risk of offspring bipolar disorder with psychotic features, but not without psychotic features. In stratified analysis, female offspring demonstrated increased risk for bipolar disorder with exposure to maternal hypothyroxinemia. No significant association was found between maternal hypothyroidism and offspring bipolar disorder.

CONCLUSIONS

These findings suggest that prenatal thyroid hormone deficiency, particularly a thyroid condition marked by low levels of thyroxine, may be an important developmental mechanism related to the risk of bipolar disorder with psychotic features.

Corticolimbic brain anomalies are associated with cognitive subtypes in psychosis: A longitudinal study

Background.

Earlier studies examining structural brain abnormalities associated with cognitively derived subgroups were mainly cross-sectional in design and had mixed findings. Thus, we obtained cross-sectional and longitudinal data to characterize the extent and trajectory of brain structure abnormalities underlying distinct cognitive subtypes (“preserved,” “deteriorated,” and “compromised”) seen in psychotic spectrum disorders.

Methods.

Data from 364 subjects (225 patients with psychotic conditions and 139 healthy controls) were first used to determine the relationship of cognitive subtypes with cross-sectional measures of subcortical volume and cortical thickness. To probe neurodevelopmental abnormalities, brain structure laterality was examined. To examine whether neuroprogressive abnormalities persist, longitudinal brain structural changes over 5 years were examined within a subset of 101 subjects. Subsequent discriminant analysis using the identified brain measures was performed on an independent subject group.

Results.

Cross-sectional comparisons showed that cortical thinning and limbic volume reductions were most widespread in “deteriorated” cognitive subtype. Laterality comparisons showed more rightward amygdala lateralization in “compromised” than “preserved” subtype. Longitudinal comparisons revealed progressive hippocampal shrinkage in “deteriorated” compared with healthy controls and “preserved” subtype, which correlated with worse negative symptoms, cognitive and psychosocial functioning. Post-hoc discrimination analysis on an independent group of 52 subjects using the identified brain structures found an overall accuracy of 71% for classification of cognitive subtypes.

Conclusion.

These findings point toward distinct extent and trajectory of corticolimbic abnormalities associated with cognitive subtypes in psychosis, which can allow further understanding of the biological course of cognitive functioning over illness course and with treatment.

P50 inhibition deficit in patients with chronic schizophrenia: Relationship with cognitive impairment of MATRICS consensus cognitive battery

OBJECTIVE

Cognitive impairment is a core symptom of schizophrenia (SCZ); however, its pathophysiological mechanisms remain unclear. The sensory gating (SG) deficits reflected by P50 inhibition are recurring in SCZ, and this inhibition may be related to the cognitive deficits seen in these individuals. This study aimed to investigate the relationship between P50 inhibition and cognitive dysfunction in SCZ, which has not been fully investigated up to this point.

METHODS

A total of 270 individuals with chronic SCZ and 116 healthy controls were enrolled in the study. Psychopathology of SCZ was rated by the positive and negative syndrome scale (PANSS), while cognitive function and P50 inhibition of subjects were assessed by the MATRICS Consensus Cognitive Battery (MCCB) and the electroencephalography system.

RESULTS

The MCCB total and its 10 index scores were significantly lower in patients than those in healthy controls (all p < 0.001). SCZ patients had a lower amplitude of S1, and higher P50 ratio than healthy controls (both p < 0.01). However, there were no significant correlations between the P50 ratio and any of the PANSS total and its subscale scores in SCZ patients (all p > 0.05). Moreover, no correlation was found between the P50 components and the MCCB scores (all p > 0.05).

CONCLUSIONS

Our findings suggest that the P50 inhibition deficits occur in Chinese individuals with SCZ, which may not be associated with their clinical symptoms and cognitive impairment.

The effect of second-generation antipsychotics on basal ganglia and thalamus in first-episode psychosis patients

Patients who have recently experienced a first of episode psychosis (FEP) exhibit considerable heterogeneity in subcortical brain volumes. These results become even more divergent when exploring the effect of antipsychotic medication among other clinical and cognitive features. We aimed to contrast volumetric measures in basal ganglia and thalamus in patients with a FEP treated with different second-generation antipsychotics. T1-weighted magnetic resonance images were obtained and subcortical structures were extracted with MAGeT-Brain. Relationships with cognitive functioning were also explored with a Global Cognitive Index obtained, on average, within one month from the scan. Subgroups included: risperidone (n = 26), aripiprazole (n = 22), olanzapine (n = 19) and controls (n = 80). The olanzapine subgroup displayed significant enlargement of the right globus pallidus volume compared with all other groups. Moreover, despite not exhibiting poorer cognitive capacity than the rest of patients, results from a stepwise multiple-regression linear regression analysis identified a significant negative association between right globus pallidus volume and scores on the Global Cognitive Index among these patients. To our knowledge, this is the first study to associate treatment with olanzapine with an increase in globus pallidus volume in a sample of FEP patients with a relatively short time of antipsychotic monotherapy. Such enlargement was also found to be associated with poorer global cognitive functioning. Exploration of the biological underpinnings of this early medication-induced enlargement should be the focus of future investigations since it may lend insight towards achieving a better clinical outcome for these patients.

Altered topological characteristics of morphological brain network relate to language impairment in high genetic risk subjects and schizophrenia patients

OBJECTIVE

Evidence suggests relationships between abnormalities in various cortical and subcortical brain structures and language dysfunction in individuals with schizophrenia, and to some extent in those with increased genetic risk for this diagnosis. The topological features of the structural brain network at the systems-level and their impact on language function in schizophrenia and in those at high genetic risk has been less well studied.

METHOD

Single-subject morphological brain network was constructed in a total of 71 subjects (20 patients with schizophrenia, 19 individuals at high genetic risk for schizophrenia, and 32 controls). Among these 71 subjects, 56 were involved in our previous neuroimaging studies. Graphic Theoretical Techniques was applied to calculate the global and nodal topological characteristics of the morphological brain network of each participant. Index scores for five language-related cognitive tests were also attained from each participant.

RESULTS

Significantly smaller nodal degree in bilateral superior occipital gyri (SOG) were observed in individuals with schizophrenia, as compared to the controls and those at high risk; while significantly reduced nodal betweenness centrality (quantifying the level of a node in connecting other nodes in the network) in right middle frontal gyrus (MFG) was found in the high-risk group, relative to controls. The right MFG nodal efficiency and hub capacity (represented by both nodal degree and betweenness centrality) of the morphological brain network were negatively associated with the wide range achievement test (WRAT) standard performance score; while the right SOG nodal degree was positively associated with the WRAT standard performance score, in the entire study sample.

CONCLUSIONS

These findings enhance the understanding of structural brain abnormalities at the systems-level in individuals with schizophrenia and those at high genetic risk, which may serve as critical neural substrates for the origin of the language-related impairments and symptom manifestations of schizophrenia.

Subcortical structures and cognitive dysfunction in first episode schizophrenia

Schizophrenia is associated with widespread cortical and subcortical abnormalities. Studies examining cognitive deficits in schizophrenia have historically focused on cortical deficits; however, many subcortical areas also support cognition. We sought to determine whether deficits in subcortical gray matter are linked to neurocognitive dysfunction in patients with first-episode schizophrenia. This study included 170 patients with first-episode schizophrenia and 88 healthy controls. Clinical symptoms, neurocognitive function, and structural images were assessed. Subcortical volumes were recorded. Patients had significant deficits in all cognitive domains, including processing speed, attention, memory, executive function and social cognition. Patients also demonstrated significantly smaller volumes in the amygdala, hippocampus, thalamus, and total cortical gray matter than did controls after Bonferroni correction for multiple comparisons. Reasoning/problem solving was significantly and positively correlated with the volume of the amygdala and nucleus accumbens in patients. Positive symptoms of psychosis were positively correlated with the volume of the amygdala and nucleus accumbens. In addition, the dose of antipsychotic medication was positively correlated with the volume of the amygdala, nucleus accumbens, caudate, putamen, and pallidum. In conclusion, schizophrenia is associated with profound cognitive deficits. Our findings suggest that subcortical structures contribute to specific domains of cognitive dysfunction in first-episode schizophrenia.

Community participation factors and poor neurocognitive functioning among persons with schizophrenia

Poor neurocognitive functioning among individuals with schizophrenia is typically conceptualized as resulting from a disease process. The objective of this article is to further expand understanding of poor neurocognition beyond pathogenesis toward a perspective that also incorporates community participation factors. This article focuses on three such factors-sedentary behavior, loneliness, and poverty-that have been demonstrated to be related to neurocognition and are highly prevalent among individuals with schizophrenia. This article provides an overview of the research on each factor and discusses its possible connection to neurocognitive challenges for individuals with schizophrenia. Implications for research, policy, and practice efforts are then proposed to broaden approaches to understanding and addressing neurocognitive challenges in this population. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Comparative Study of Cognitive Function Between Treatment-Resistant Depressive Patients and First-Episode Depressive Patients

OBJECTIVE

Despite reports of cognitive dysfunction during the acute phase of depression, there is a lack of studies in patients with treatment-resistant depression (TRD). The aim of this study was to investigate the cognitive function profile of TRD and compare cognitive dysfunction between subjects with TRD and first-episode depression.

PATIENTS AND METHODS

The study included 31 patients with TRD and 53 with first-episode depression. Cognitive function was assessed by a series of neuropsychological tools such as the verbal fluency test, Modified Wisconsin Card Sorting Test (M-WCST), Tower of Hanoi test, Chinese-revision of the Wechsler Adult Intelligence Scale (WAIS-RC), and Trail Making Test A and B.

RESULTS

There were no significant demographic differences between the TRD, first-episode depression, and normal control groups (gender, age, years of education). The full-scale, verbal, and performance intelligence quotients measured with the WAIS-RC were also not significantly different (p>0.05). The normal group scores were all significantly better than TRD and first-episode depression, and the TRD group performed significantly worse than subjects with first-episode depression on Trail Making Test B, two WCST subscales, and the profile score of the Tower of Hanoi test (all p<0.05).

CONCLUSION

Patients with depression exhibited global impairments in cognitive function, and these were more common in TRD. Poor executive function may play an important role in TRD.

Motor dysfunction as research domain across bipolar, obsessive-compulsive and neurodevelopmental disorders

Although genuine motor abnormalities (GMA) are frequently found in schizophrenia, they are also considered as an intrinsic feature of bipolar, obsessive-compulsive, and neurodevelopmental disorders with early onset such as autism, ADHD, and Tourette syndrome. Such transnosological observations strongly suggest a common neural pathophysiology. This systematic review highlights the evidence on GMA and their neuroanatomical substrates in bipolar, obsessive-compulsive, and neurodevelopmental disorders. The data lends support for a common pattern contributing to GMA expression in these diseases that seems to be related to cerebello-thalamo-cortical, fronto-parietal, and cortico-subcortical motor circuit dysfunction. The identified studies provide first evidence for a motor network dysfunction as a correlate of early neurodevelopmental deviance prior to clinical symptom expression. There are also first hints for a developmental risk factor model of these mental disorders. An in-depth analysis of motor networks and related patho-(physiological) mechanisms will not only help promoting Research Domain Criteria (RDoC) Motor System construct, but also facilitate the development of novel psychopharmacological models, as well as the identification of neurobiologically plausible target sites for non-invasive brain stimulation.

Genetic Overlap Between Schizophrenia and Volumes of Hippocampus, Putamen, and Intracranial Volume Indicates Shared Molecular Genetic Mechanisms

Schizophrenia (SCZ) is associated with differences in subcortical brain volumes and intracranial volume (ICV). However, little is known about the underlying etiology of these brain alterations. Here, we explored whether brain structure volumes and SCZ share genetic risk factors. Using conditional false discovery rate (FDR) analysis, we integrated genome-wide association study (GWAS) data on SCZ (n = 82315) and GWAS data on 7 subcortical brain volumes and ICV (n = 11840). By conditioning the FDR on overlapping associations, this statistical approach increases power to discover genetic loci. To assess the credibility of our approach, we studied the identified loci in larger GWAS samples on ICV (n = 26577) and hippocampal volume (n = 26814). We observed polygenic overlap between SCZ and volumes of hippocampus, putamen, and ICV. Based on conjunctional FDR < 0.05, we identified 2 loci shared between SCZ and ICV implicating genes FOXO3 (rs10457180) and ITIH4 (rs4687658), 2 loci shared between SCZ and hippocampal volume implicating SLC4A10 (rs4664442) and SPATS2L (rs1653290), and 2 loci shared between SCZ and volume of putamen implicating DCC (rs4632195) and DLG2 (rs11233632). The loci shared between SCZ and hippocampal volume or ICV had not reached significance in the primary GWAS on brain phenotypes. Proving our point of increased power, 2 loci did reach genome-wide significance with ICV (rs10457180) and hippocampal volume (rs4664442) in the larger GWAS. Three of the 6 identified loci are novel for SCZ. Altogether, the findings provide new insights into the relationship between SCZ and brain structure volumes, suggesting that their genetic architectures are not independent.

Associations between psychosis endophenotypes across brain functional, structural, and cognitive domains

BACKGROUND

A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.

METHODS

This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.

RESULTS

The P300 amplitude and latency were not associated (regression coef. -0.06, 95% CI -0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10-0.28, p 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.

CONCLUSIONS

The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.

Role of subcortical structures on cognitive and social function in schizophrenia

Subcortical regions have a pivotal role in cognitive, affective, and social functions in humans, and the structural and functional abnormalities of the regions have been associated with various psychiatric disorders. Although previous studies focused on the neurocognitive and socio-functional consequences of prefrontal and tempolo-limbic abnormalities in psychiatric disorders, those of subcortical structures remain largely unknown. Recently, MRI volume alterations in subcortical structures in patients with schizophrenia have been replicated in large-scale meta-analytic studies. Here we investigated the relationship between volumes of subcortical structures and neurocognitive and socio-functional indices in a large sample of patients with schizophrenia. First, we replicated the results of meta-analyses: the regional volumes of the bilateral hippocampus, amygdala, thalamus and nucleus accumbens were significantly smaller for patients (N = 163) than for healthy controls (HCs, N = 620). Second, in the patient group, the right nucleus accumbens volume was significantly correlated with the Digit Symbol Coding score, which is known as a distinctively characteristic index of cognitive deficits in schizophrenia. Furthermore, the right thalamic volume was significantly correlated with social function scores. In HCs, no significant correlation was found. The results from this large-scale investigation shed light upon the role of specific subcortical nuclei on cognitive and social functioning in schizophrenia.

Subcortical association with memory performance in schizophrenia: a structural magnetic resonance imaging study

Memory performance is severely impaired in individuals with schizophrenia. Although several studies have reported a relationship between memory performance and hippocampal volume, only a few structural magnetic resonance imaging (MRI) studies have investigated the relationship between memory performance and subcortical structures other than hippocampus in patients with schizophrenia. We investigated the relationship between memory performance and subcortical regional volumes in a large sample of patients with schizophrenia. Participants included 174 patients with schizophrenia and 638 healthy comparison subjects (HCS). The Wechsler Memory Scale-Revised (WMS-R) has three memory indices (verbal immediate recall, visual immediate recall, and delayed recall (verbal plus visual)) and one control neurocognitive index (attention/concentration). We obtained T1-weighted MRI data and measured the bilateral volumes of the hippocampus, amygdala, thalamus, nucleus accumbens (NA), caudate, putamen, and globus pallidus. Patients with schizophrenia had significantly lower scores for all of the indices of the WMS-R than the HCS. They had more severe impairments in verbal immediate recall and delayed recall than in visual immediate recall and attention/concentration. Verbal immediate recall/delayed recall scores in patients with schizophrenia were significantly correlated not only with hippocampal volume (left: r = 0.34; right: r = 0.28/left: r = 0.33; right: r = 0.31), but also with NA volume (left: r = 0.24; right: r = 0.25/left: r = 0.26; right: r = 0.27). The present investigation with a large sample size did not only replicate hippocampal volume and memory association, but also found that NA volume is associated with memory performances in schizophrenia.

Biochemical abnormalities in basal ganglia and executive dysfunction in acute- and euthymic-episode patients with bipolar disorder: A proton magnetic resonance spectroscopy study

BACKGROUND

Recent studies found abnormal biochemical metabolism and executive cognitive deficits in acute bipolar disorder (BD). However, the evidence concerning in euthymic BD is limited. Thus, a comparison between acute and euthymic BD is conductive to better understanding the association between cognition and the outcome of neuroimaging. This study sought to investigate the relationship between the executive function and the biochemical metabolism in acute- and euthymic-episode BD patients and delineate the prominent endophenotype of BD.

METHODS

Three groups of participants were recruited in this study: 30 BD patients with an acute depressive episode, 22 euthymic BD patients, and 31 healthy controls. All participants were interviewed using the Structured Clinical Interview for DSM-IV, and underwent two-dimensional multivoxel proton magnetic resonance spectroscopy (1H-MRS) to obtain the bilateral metabolite levels in the lenticular nucleus of basal ganglia(BG). The ratios of N-acetylaspartate (NAA)/creatine (Cr) and Choline-containing compounds (Cho) /Cr ratios were calculated. Executive function was assessed by using the Wisconsin Card Sorting Test (WCST) and Trail Making Test, Part-B(TMT-B).

RESULTS

The comparison of biochemical changes showed that the NAA/Cr ratios in bilateral lenticular nucleus in both acute and euthymic BD patients was significantly lower than that in healthy controls at a confidence level of p<0.05. In the comparison of executive function, both acute and euthymic BD patients showed significantly decreased numbers of categories completed, and increased numbers of total errors, perseverative and noperseverative errors, and TMT-B uptake compared to the healthy controls at a confidence level of p<0.05. There were no significant differences between the acute BD and euthymic BD groups in the biochemical metabolite ratios and executive function. We found that the NAA/Cr ratio in the left in BG in the acute -episode BD patients was positively correlated with the number of categories completed, whereas it was negatively correlated with the total errors and TMT-B uptake. There was no correlation between the NAA/Cr and Cho/Cr ratios in the bilateral BG and the scores of SWCT and TMT-B in euthymic-episode BD patients.

LIMITATION

The sample size was relatively small and not all the euthymic-episode patients are the ones with an acute episode.

CONCLUSIONS

Our findings suggest that biochemical abnormalities in the lenticular nucleus and the executive dysfunction may occur early in the course of BD, and persist during remission, and are the most likely markers of endophenotypes of BD. The dysfunction of the neuronal function in the lenticular nucleus may be correlated with the cold dysfunction in patients with acute BD.

The relationship between brain volumes and intelligence in bipolar disorder

OBJECTIVES

Bipolar disorder type-I (BD-I) patients show a lower Intelligence Quotient (IQ) and smaller brain volumes as compared with healthy controls. Considering that in healthy individuals lower IQ is related to smaller total brain volume, it is of interest to investigate whether IQ deficits in BD-I patients are related to smaller brain volumes and to what extent smaller brain volumes can explain differences between premorbid IQ estimates and IQ after a diagnosis of BD-I.

METHODS

Magnetic resonance imaging brain scans, IQ and premorbid IQ scores were obtained from 195 BDI patients and 160 controls. We studied the relationship of (global, cortical and subcortical) brain volumes with IQ and IQ change. Additionally, we investigated the relationship between childhood trauma, lithium- and antipsychotic use and IQ.

RESULTS

Total brain volume and IQ were positively correlated in the entire sample. This correlation did not differ between patients and controls. Although brain volumes mediated the relationship between BD-I and IQ in part, the direct relationship between the diagnosis and IQ remained significant. Childhood trauma and use of lithium and antipsychotic medication did not affect the relationship between brain volumes and IQ. However, current lithium use was related to lower IQ in patients.

CONCLUSIONS

Our data suggest a similar relationship between brain volume and IQ in BD-I patients and controls. Smaller brain volumes only partially explain IQ deficits in patients. Therefore, our findings indicate that in addition to brain volumes and lithium use other disease factors play a role in IQ deficits in BD-I patients.

Cortical complexity in bipolar disorder applying a spherical harmonics approach

Recent studies using surface-based morphometry of structural magnetic resonance imaging data have suggested that some changes in bipolar disorder (BP) might be neurodevelopmental in origin. We applied a novel analysis of cortical complexity based on fractal dimensions in high-resolution structural MRI scans of 18 bipolar disorder patients and 26 healthy controls. Our region-of-interest based analysis revealed increases in fractal dimensions (in patients relative to controls) in left lateral orbitofrontal cortex and right precuneus, and decreases in right caudal middle frontal, entorhinal cortex, and right pars orbitalis, and left fusiform and posterior cingulate cortices. While our analysis is preliminary, it suggests that early neurodevelopmental pathologies might contribute to bipolar disorder, possibly through genetic mechanisms.

Brain structure, function, and neurochemistry in schizophrenia and bipolar disorder-a systematic review of the magnetic resonance neuroimaging literature

Since Emil Kraepelin's conceptualization of endogenous psychoses as dementia praecox and manic depression, the separation between primary psychotic disorders and primary affective disorders has been much debated. We conducted a systematic review of case-control studies contrasting magnetic resonance imaging studies in schizophrenia and bipolar disorder. A literature search in PubMed of studies published between January 2005 and December 2016 was conducted, and 50 structural, 29 functional, 7 magnetic resonance spectroscopy, and 8 combined imaging and genetic studies were deemed eligible for systematic review. Structural neuroimaging studies suggest white matter integrity deficits that are consistent across the illnesses, while gray matter reductions appear more widespread in schizophrenia compared to bipolar disorder. Spectroscopy studies in cortical gray matter report evidence of decreased neuronal integrity in both disorders. Functional neuroimaging studies typically report similar functional architecture of brain networks in healthy controls and patients across the psychosis spectrum, but find differential extent of alterations in task related activation and resting state connectivity between illnesses. The very limited imaging-genetic literature suggests a relationship between psychosis risk genes and brain structure, and possible gene by diagnosis interaction effects on functional imaging markers. While the existing literature suggests some shared and some distinct neural markers in schizophrenia and bipolar disorder, it will be imperative to conduct large, well designed, multi-modal neuroimaging studies in medication-naïve first episode patients that will be followed longitudinally over the course of their illness in an effort to advance our understanding of disease mechanisms.

Using deep belief network modelling to characterize differences in brain morphometry in schizophrenia

Neuroimaging-based models contribute to increasing our understanding of schizophrenia pathophysiology and can reveal the underlying characteristics of this and other clinical conditions. However, the considerable variability in reported neuroimaging results mirrors the heterogeneity of the disorder. Machine learning methods capable of representing invariant features could circumvent this problem. In this structural MRI study, we trained a deep learning model known as deep belief network (DBN) to extract features from brain morphometry data and investigated its performance in discriminating between healthy controls (N = 83) and patients with schizophrenia (N = 143). We further analysed performance in classifying patients with a first-episode psychosis (N = 32). The DBN highlighted differences between classes, especially in the frontal, temporal, parietal, and insular cortices, and in some subcortical regions, including the corpus callosum, putamen, and cerebellum. The DBN was slightly more accurate as a classifier (accuracy = 73.6%) than the support vector machine (accuracy = 68.1%). Finally, the error rate of the DBN in classifying first-episode patients was 56.3%, indicating that the representations learned from patients with schizophrenia and healthy controls were not suitable to define these patients. Our data suggest that deep learning could improve our understanding of psychiatric disorders such as schizophrenia by improving neuromorphometric analyses.

Abnormal asymmetries in subcortical brain volume in schizophrenia

Subcortical structures, which include the basal ganglia and parts of the limbic system, have key roles in learning, motor control and emotion, but also contribute to higher-order executive functions. Prior studies have reported volumetric alterations in subcortical regions in schizophrenia. Reported results have sometimes been heterogeneous, and few large-scale investigations have been conducted. Moreover, few large-scale studies have assessed asymmetries of subcortical volumes in schizophrenia. Here, as a work completely independent of a study performed by the ENIGMA consortium, we conducted a large-scale multisite study of subcortical volumetric differences between patients with schizophrenia and controls. We also explored the laterality of subcortical regions to identify characteristic similarities and differences between them. T1-weighted images from 1680 healthy individuals and 884 patients with schizophrenia, obtained with 15 imaging protocols at 11 sites, were processed with FreeSurfer. Group differences were calculated for each protocol and meta-analyzed. Compared with controls, patients with schizophrenia demonstrated smaller bilateral hippocampus, amygdala, thalamus and accumbens volumes as well as intracranial volume, but larger bilateral caudate, putamen, pallidum and lateral ventricle volumes. We replicated the rank order of effect sizes for subcortical volumetric changes in schizophrenia reported by the ENIGMA consortium. Further, we revealed leftward asymmetry for thalamus, lateral ventricle, caudate and putamen volumes, and rightward asymmetry for amygdala and hippocampal volumes in both controls and patients with schizophrenia. Also, we demonstrated a schizophrenia-specific leftward asymmetry for pallidum volume. These findings suggest the possibility of aberrant laterality in neural pathways and connectivity patterns related to the pallidum in schizophrenia.

Reduced hippocampus volume and memory performance in bipolar disorder patients carrying the BDNF val66met met allele

BACKGROUND

Previous studies investigated the impact of brain-derived neurotrophic factor (BDNF) val66met (rs6265) on hippocampus volumes and neurocognition in bipolar disorders (BD), but the results were not consistent. This study aimed to investigate the effect of BDNF polymorphism on hippocampus volumes and memory performance in well-characterized adult populations diagnosed with type I BD (BD-I) and major depressive disorder (MDD) compared with healthy controls (HC).

METHODS

48 BD-I patients, 33 MDD patients and 60 HC were genotyped for BDNF rs6265 using DNA isolated from white blood cells. Individuals with val/met and met/met genotypes were grouped as met carriers and compared to those with the val/val. Brain segmentations were obtained from structural magnetic resonance imaging (MRI) using the Freesurfer. Memory performance was assessed with the California Verbal Learning Task (CVLT).

RESULTS

We found a significant diagnosis effect and marginal interaction between diagnosis and BDNF genotype group for both hippocampus volumes and memory performance. BDNF met allele carrier BD patients had smaller hippocampus volumes and reduced performance on multiple CVLT scores compared to MDD patients and HC.

CONCLUSIONS

We provide strong evidence for the BDNF val66met polymorphism as a putative biological signature for the neuroanatomical and cognitive abnormalities commonly observed in BD patients.

Can neuroimaging disentangle bipolar disorder?

BACKGROUND

Bipolar disorder heterogeneity is large, leading to difficulties in identifying neuropathophysiological and etiological mechanisms and hindering the formation of clinically homogeneous patient groups in clinical trials. Identifying markers of clinically more homogeneous groups would help disentangle BD heterogeneity. Neuroimaging may aid in identifying such groups by highlighting specific biomarkers of BD subtypes or clinical dimensions.

METHODS

We performed a systematic literature search of the neuroimaging literature assessing biomarkers of relevant BD phenotypes (type-I vs. II, presence vs. absence of psychotic features, suicidal behavior and impulsivity, rapid cycling, good vs. poor medication response, age at onset, cognitive performance and circadian abnormalities).

RESULTS

Consistent biomarkers were associated with suicidal behavior, i.e. frontal/anterior alterations (prefrontal and cingulate grey matter, prefrontal white matter) in patients with a history of suicide attempts; and with cognitive performance, i.e. involvement of frontal and temporal regions, superior and inferior longitudinal fasciculus, right thalamic radiation, and corpus callosum in executive dysfunctions. For the other dimensions and sub-types studied, no consistent biomarkers were identified.

LIMITATIONS

Studies were heterogeneous both in methodology and outcome.

CONCLUSIONS

Though theoretically promising, neuroimaging has not yet proven capable of disentangling subtypes and dimensions of bipolar disorder, due to high between-study heterogeneity. We issue recommendations for future studies.

Apolipoprotein E genotype is not associated with cognitive impairment in older adults with bipolar disorder

OBJECTIVES

Cognitive decline is part of the long-term outcome for many individuals with bipolar disorder (BD). The ε4 allele (APOE*4) of apolipoprotein E (APOE) is a well-established risk factor for dementia in Alzheimer's disease (AD). However, its contribution to the risk of cognitive deterioration in BD has not yet been determined. Our aim was to analyze the APOE genotype association with cognitive status in a sample of older adults with BD and compare this to the association in individuals with AD, individuals with mild cognitive impairment (MCI), and healthy controls.

METHODS

Participants (n = 475) were allocated to four groups: individuals with BD (n = 77), those with AD (n = 211), those with MCI (n = 43), and healthy controls (n = 144) according to clinical and neuropsychological assessment. APOE was genotyped by real-time polymerase chain reaction. Tukey's honest significant difference test and Pearson's chi-squared test were used to compare diagnostic groups.

RESULTS

Subjects with BD were similar to controls with respect to the distribution of the APOE genotype (p = 0.636) and allele frequencies (p = 0.481). Significant differences were found when comparing the AD group to the BD group or to controls (APOE genotype: p < 0.0002; allele frequencies: p < 0.001). APOE*4 was significantly increased in the AD group when compared to the BD group (p = 0.031) and controls (p < 0.0001). The cognitively impaired BD subgroup (Mini-Mental State Examination below the cutoff score and/or neuropsychological assessment compatible with MCI) had a statistically significant higher frequency of APOE*2 compared to the AD group (p = 0.003).

CONCLUSIONS

APOE*4 is not associated with the diagnosis of BD and does not impact the occurrence of dementia in BD. Given the distinct clinical and biological features of cognitive impairment in BD, we hypothesized that dementia in BD is unrelated to AD pathological mechanisms.

[Relationship between subclinical psychotic symptoms and cognitive performance in the general population]

INTRODUCTION

Subclinical psychotic symptoms are associated to negative life outcomes in the general population, but their relationship with cognitive performance is still not well understood. Assessing the relationship between performance in cognitive domains and subclinical psychotic symptoms in the general population may also help understand the handicap attributed to clinical psychosis, in which these alterations are present.

METHODS

Subclinical and cognitive assessments were obtained in 203 participants from the general population by means of the Community Assessment of Psychic Experiences, the Brief Assessment of Cognition in Schizophrenia, the Wechsler Adults Intelligence Scale and the Wisconsin Card Sorting Test. The positive and negative subclinical symptoms and their relationship with age and cognition were examined, followed by assessing the influence of subclinical depression scores on the possible relationships between those subclinical psychotic symptoms and cognitive deficits.

RESULTS

Inverse relationships were found between frequency in the Community Assessment of Psychic Experiences positive dimension and motor speed, and frequency and distress in the Community Assessment of Psychic Experiences negative dimension and motor speed. A direct relationship was also found between distress scores of the positive dimension and executive functions. Both positive and negative subclinical symptoms were related to depression scores.

CONCLUSIONS

Psychotic symptoms, similar to those in the clinical population, may be associated with cognitive deficits in the general population.

Baseline putamen volume as a predictor of positive symptom reduction in patients at clinical high risk for psychosis: A preliminary study

OBJECTIVES

Illness course in individuals at clinical high risk (CHR) status for psychosis is heterogeneous, which limits effective treatment for all CHR subgroups. Baseline predictors of positive symptom trajectory in the CHR group will reduce such limitations. We singled out the putamen, thought to be involved in the generation of the key schizophrenia symptoms early in the course of disease, as a potential predictor of positive symptom trajectory in CHR patients.

METHOD

We recruited 45 CHR patients and 29 age- and gender-matched healthy controls (HC). The CHR group was divided into patients with positive symptom reduction (CHR-R) and patients without positive symptom reduction (CHR-NR) at 6 months. Comparisons were made between the baseline putamen volumes of CHR-R, CHR-NR and HC groups. The relationship between baseline putamen volumes and clinical measures was investigated.

RESULTS

Left putamen volumes of CHR-R patients were significantly smaller than those of HCs (p=0.002) and of CHR-NR patients (p=0.024). CHR-R patients had significantly reduced leftward laterality compared to HCs (p=0.007). In the CHR-R group, bilateral putamen volumes were correlated with positive symptom severity at baseline (r=-0.552, p=0.001) and at 6 months (r=-0.360, p=0.043), and predicted positive symptom score change in 6 months at a trend level (p=0.092).

CONCLUSION

Smaller left putamen volumes in CHR-R patients, and the correlation between positive symptom severity and putamen volumes suggest that putamen volume is a possible risk-stratifier and predictor of clinical course in the CHR population.

Subcortical structure alterations impact language processing in individuals with schizophrenia and those at high genetic risk

OBJECTIVE

Cortical structural and functional anomalies have been found to associate with language impairments in both schizophrenia patients and genetic high risk individuals for developing schizophrenia. However, subcortical structures that contribute to language processing haven't been well studied in this population, and thus became the main objective of this study.

METHOD

We examined structural MRI data from 20 patients with schizophrenia, 21 individuals at genetic high risk, and 48 controls. Surface shape and volume differences of 6 subcortical structures that are involved in language processing, including nuclei pallidum, putamen, caudate, amygdala, thalamus, and hippocampus from both hemispheres, were compared between groups. Performance scores of language-associated cognitive tests were obtained to identify relationships of subcortical structures to language-related behaviors.

RESULTS

Significantly reduced volumes of both the left and right side caudate nuclei, thalami and right side amygdala were shown in patients when compared with controls. Very interestingly, the high risk group demonstrated significantly increased correlations between volumes of left side pallidum nucleus and bilateral thalami and language-related cognitive test scores when compared to controls.

CONCLUSIONS

This study furthers our understanding of subcortical structural alterations in schizophrenia and high risk individuals, and suggests the contribution of subcortical structures to the language impairments that may serve as an early sign for impending development of schizophrenia.

NCAN Cross-Disorder Risk Variant Is Associated With Limbic Gray Matter Deficits in Healthy Subjects and Major Depression

Genome-wide association studies have reported an association between NCAN rs1064395 genotype and bipolar disorder. This association was later extended to schizophrenia and major depression. However, the neurobiological underpinnings of these associations are poorly understood. NCAN is implicated in neuronal plasticity and expressed in subcortical brain areas, such as the amygdala and hippocampus, which are critically involved in dysfunctional emotion processing and regulation across diagnostic boundaries. We hypothesized that the NCAN risk variant is associated with reduced gray matter volumes in these areas. Gray matter structure was assessed by voxel-based morphometry on structural MRI data in two independent German samples (healthy subjects, n=512; depressed inpatients, n=171). All participants were genotyped for NCAN rs1064395. Hippocampal and amygdala region-of-interest analyses were performed within each sample. In addition, whole-brain data from the combined sample were analyzed. Risk (A)-allele carriers showed reduced amygdala and hippocampal gray matter volumes in both cohorts with a remarkable spatial overlap. In the combined sample, genotype effects observed for the amygdala and hippocampus survived correction for entire brain volume. Further effects were also observed in the left orbitofrontal cortex and the cerebellum/fusiform gyrus. We conclude that NCAN genotype is associated with limbic gray matter alterations in healthy and depressed subjects in brain areas implicated in emotion perception and regulation. The present data suggest that NCAN forms susceptibility to neurostructural deficits in the amygdala, hippocampus, and prefrontal areas independent of disease, which might lead to disorder onset in the presence of other genetic or environmental risk factors.

Task-rest modulation of basal ganglia connectivity in mild to moderate Parkinson's disease

Parkinson's disease (PD) is associated with abnormal synchronization in basal ganglia-thalamo-cortical loops. We tested whether early PD patients without demonstrable cognitive impairment exhibit abnormal modulation of functional connectivity at rest, while engaged in a task, or both. PD and healthy controls underwent two functional MRI scans: a resting-state scan and a Stroop Match-to-Sample task scan. Rest-task modulation of basal ganglia (BG) connectivity was tested using seed-to-voxel connectivity analysis with task and rest time series as conditions. Despite substantial overlap of BG-cortical connectivity patterns in both groups, connectivity differences between groups had clinical and behavioral correlates. During rest, stronger putamen-medial parietal and pallidum-occipital connectivity in PD than controls was associated with worse task performance and more severe PD symptoms suggesting that abnormalities in resting-state connectivity denote neural network dedifferentiation. During the executive task, PD patients showed weaker BG-cortical connectivity than controls, i.e., between caudate-supramarginal gyrus and pallidum-inferior prefrontal regions, that was related to more severe PD symptoms and worse task performance. Yet, task processing also evoked stronger striatal-cortical connectivity, specifically between caudate-prefrontal, caudate-precuneus, and putamen-motor/premotor regions in PD relative to controls, which was related to less severe PD symptoms and better performance on the Stroop task. Thus, stronger task-evoked striatal connectivity in PD demonstrated compensatory neural network enhancement to meet task demands and improve performance levels. fMRI-based network analysis revealed that despite resting-state BG network compromise in PD, BG connectivity to prefrontal, premotor, and precuneus regions can be adequately invoked during executive control demands enabling near normal task performance.

Impaired Verbal Learning Is Associated with Larger Caudate Volumes in Early Onset Schizophrenia Spectrum Disorders

Background

Both brain structural abnormalities and neurocognitive impairments are core features of schizophrenia. We have previously reported enlargements in subcortical brain structure volumes and impairment of neurocognitive functioning as measured by the MATRICS Cognitive Consensus Battery (MCCB) in early onset schizophrenia spectrum disorders (EOS). To our knowledge, no previous study has investigated whether neurocognitive performance and volumetric abnormalities in subcortical brain structures are related in EOS.

Methods

Twenty-four patients with EOS and 33 healthy controls (HC) were included in the study. Relationships between the caudate nucleus, the lateral and fourth ventricles volumes and neurocognitive performance were investigated with multivariate linear regression analyses. Intracranial volume, age, antipsychotic medication and IQ were included as independent predictor-variables.

Results

The caudate volume was negatively correlated with verbal learning performance uniquely in the EOS group (r=-.454, p=.034). There were comparable positive correlations between the lateral ventricular volume and the processing speed, attention and reasoning and problem solving domains for both the EOS patients and the healthy controls. Antipsychotic medication was related to ventricular enlargements, but did not affect the brain structure-function relationship.

Conclusion

Enlargement of the caudate volume was related to poorer verbal learning performance in patients with EOS. Despite a 32% enlargement of the lateral ventricles in the EOS group, associations to processing speed, attention and reasoning and problem solving were similar for both the EOS and the HC groups.

Brain structure-function associations in multi-generational families genetically enriched for bipolar disorder

Recent theories regarding the pathophysiology of bipolar disorder suggest contributions of both neurodevelopmental and neurodegenerative processes. While structural neuroimaging studies indicate disease-associated neuroanatomical alterations, the behavioural correlates of these alterations have not been well characterized. Here, we investigated multi-generational families genetically enriched for bipolar disorder to: (i) characterize neurobehavioural correlates of neuroanatomical measures implicated in the pathophysiology of bipolar disorder; (ii) identify brain-behaviour associations that differ between diagnostic groups; (iii) identify neurocognitive traits that show evidence of accelerated ageing specifically in subjects with bipolar disorder; and (iv) identify brain-behaviour correlations that differ across the age span. Structural neuroimages and multi-dimensional assessments of temperament and neurocognition were acquired from 527 (153 bipolar disorder and 374 non-bipolar disorder) adults aged 18-87 years in 26 families with heavy genetic loading for bipolar disorder. We used linear regression models to identify significant brain-behaviour associations and test whether brain-behaviour relationships differed: (i) between diagnostic groups; and (ii) as a function of age. We found that total cortical and ventricular volume had the greatest number of significant behavioural associations, and included correlations with measures from multiple cognitive domains, particularly declarative and working memory and executive function. Cortical thickness measures, in contrast, showed more specific associations with declarative memory, letter fluency and processing speed tasks. While the majority of brain-behaviour relationships were similar across diagnostic groups, increased cortical thickness in ventrolateral prefrontal and parietal cortical regions was associated with better declarative memory only in bipolar disorder subjects, and not in non-bipolar disorder family members. Additionally, while age had a relatively strong impact on all neurocognitive traits, the effects of age on cognition did not differ between diagnostic groups. Most brain-behaviour associations were also similar across the age range, with the exception of cortical and ventricular volume and lingual gyrus thickness, which showed weak correlations with verbal fluency and inhibitory control at younger ages that increased in magnitude in older subjects, regardless of diagnosis. Findings indicate that neuroanatomical traits potentially impacted by bipolar disorder are significantly associated with multiple neurobehavioural domains. Structure-function relationships are generally preserved across diagnostic groups, with the notable exception of ventrolateral prefrontal and parietal association cortex, volumetric increases in which may be associated with cognitive resilience specifically in individuals with bipolar disorder. Although age impacted all neurobehavioural traits, we did not find any evidence of accelerated cognitive decline specific to bipolar disorder subjects. Regardless of diagnosis, greater global brain volume may represent a protective factor for the effects of ageing on executive functioning.

Brain structure characteristics in intellectually superior schizophrenia

The current study aims to fill a gap in the knowledge base by investigating the structural brain characteristics of individuals with schizophrenia and superior intellectual abilities. Subcortical volumes, cortical thickness and cortical surface area were examined in intellectually normal and intellectually superior participants with schizophrenia and their IQ-matched healthy controls, as well as in intellectually low schizophrenia participants. We replicated significant diagnostic group effects on hippocampal and ventricular size after correction for multiple comparisons. There were no statistically significant effects of intellectual level or of the interaction between diagnostic group and intellectual level. Effect sizes indicated that differences between schizophrenia and healthy control participants were of similar magnitude at both intellectual levels for all three types of morphological data. A secondary analysis within the schizophrenia group, including participants with low intellectual abilities, yielded numerical, but no statistically significant differences on any structural brain measure. The present findings indicate that the brain structure abnormalities in schizophrenia are present at all intellectual levels, and individuals with schizophrenia and superior intellectual abilities have brain structure abnormalities of the same magnitude as individuals with schizophrenia and normal intellectual abilities.

Implicit motor learning in bipolar disorder

OBJECTIVES

A growing number of publications describe cerebellar abnormalities in patients with bipolar disorder (BD). The aim of the following paper was to examine the functional aspects of that issue by focusing on implicit learning - a cognitive function with significant cerebellar underpinnings.

METHODS

27 patients with BD and 26 healthy controls (HC), matched for age and sex took part in the study. Implicit motor learning was assessed by the serial reaction time task (SRTT), in which participants were unconsciously learning a sequence of motor reactions. The indicators of procedural learning were the decrease of reaction time (RT) across the repetition of the sequence and the rebound of RT when the sequence changed into a random set of stimuli.

RESULTS

BD patients did not present any indicators of the implicit learning, their RT increased across repetitions of the sequence and it decreased when the sequence changed to random. Contrary, in the control group RT decreased across the sequence repetitions and increased when the stimuli begun to appear randomly.

LIMITATIONS

A low subject count and a non-drug naïve patients group, medicated with atypical antipsychotic and mood stabilizers, are the most significant limitations of this study.

CONCLUSIONS

BD patients did not acquire procedural knowledge while performing the task, whereas HC did. To our knowledge this is the first study that shows the impairment of implicit motor learning in patients with BD. This indicates the possible cerebellar dysfunction in this disease and may provide a new neuropsychiatric approach to bipolar disorder.

Occipital bending (Yakovlevian torque) in bipolar depression

Differing levels of occipital lobe asymmetry and enlarged lateral ventricles have been reported within patients with bipolar disorder (BD) compared with healthy controls, suggesting different rates of occipital bending (OB). This may exert pressure on subcortical structures, such as the hippocampus, reduced among psychiatric patients. We investigated OB prevalence in 35 patients with BD and 36 healthy controls, and ventricular and occipital volumes. Prevalence was four times higher among BD patients (12/35 [34.3%]) than in control subjects (3/36 [8.3%]), as well as larger lateral ventricular volumes (LVVs). Furthermore, we found OB to relate to left-to-right ventricular and occipital lobe volume (OLV) ratios. Those with OB also had reduced left-to-right hippocampal volume ratios. The results suggest that OB is more common among BD patients than healthy subjects, and prevalent in both BD Type I and Type II patients. We posit that anomalies in neural pruning or ventricular enlargement may precipitate OB, consequently resulting in one occipital lobe twisting around the other. Although the clinical implications of these results are unclear, the study suggests that asymmetrical ventricular volume matched with a pattern of oppositely asymmetrical occipital volume is related to OB and may be a marker of psychiatric illness.