Basal ganglia anatomy and schizophrenia: the role of antipsychotic treatment

Resting-State Brain Activity Dysfunctions in Schizophrenia and Their Associations with Negative Symptom Domains: An fMRI Study

The aim of the present study was to examine the neurobiological correlates of the two negative symptom domains of schizophrenia, the Motivational Deficit domain (including avolition, anhedonia, and asociality) and the Expressive Deficit domain (including blunted affect and alogia), focusing on brain areas that are most commonly found to be associated with negative symptoms in previous literature. Resting-state (rs) fMRI data were analyzed in 62 subjects affected by schizophrenia (SZs) and 46 healthy controls (HCs). The SZs, compared to the HCs, showed higher rs brain activity in the right inferior parietal lobule and the right temporoparietal junction, and lower rs brain activity in the right dorsolateral prefrontal cortex, the bilateral anterior dorsal cingulate cortex, and the ventral and dorsal caudate. Furthermore, in the SZs, the rs brain activity in the left orbitofrontal cortex correlated with negative symptoms (r = -0.436, p = 0.006), in particular with the Motivational Deficit domain (r = -0.424, p = 0.002), even after controlling for confounding factors. The left ventral caudate correlated with negative symptoms (r = -0.407, p = 0.003), especially with the Expressive Deficit domain (r = -0.401, p = 0.003); however, these results seemed to be affected by confounding factors. In line with the literature, our results demonstrated that the two negative symptom domains might be underpinned by different neurobiological mechanisms.

Associations of medication with subcortical morphology across the lifespan in OCD: Results from the international ENIGMA Consortium

BACKGROUND

Widely used psychotropic medications for obsessive-compulsive disorder (OCD) may change the volumes of subcortical brain structures, and differently in children vs. adults. We measured subcortical volumes cross-sectionally in patients finely stratified for age taking various common classes of OCD drugs.

METHODS

The ENIGMA-OCD consortium sample (1081 medicated/1159 unmedicated OCD patients and 2057 healthy controls aged 6-65) was divided into six successive 6-10-year age-groups. Individual structural MRIs were parcellated automatically using FreeSurfer into 8 regions-of-interest (ROIs). ROI volumes were compared between unmedicated and medicated patients and controls, and between patients taking serotonin reuptake inhibitors (SRIs), tricyclics (TCs), antipsychotics (APs), or benzodiazepines (BZs) and unmedicated patients.

RESULTS

Compared to unmedicated patients, volumes of accumbens, caudate, and/or putamen were lower in children aged 6-13 and adults aged 50-65 with OCD taking SRIs (Cohen's d = -0.24 to -0.74). Volumes of putamen, pallidum (d = 0.18-0.40), and ventricles (d = 0.31-0.66) were greater in patients aged 20-29 receiving APs. Hippocampal volumes were smaller in patients aged 20 and older taking TCs and/or BZs (d = -0.27 to -1.31).

CONCLUSIONS

Results suggest that TCs and BZs could potentially aggravate hippocampal atrophy of normal aging in older adults with OCD, whereas SRIs may reduce striatal volumes in young children and older adults. Similar to patients with psychotic disorders, OCD patients aged 20-29 may experience subcortical nuclear and ventricular hypertrophy in relation to APs. Although cross-sectional, present results suggest that commonly prescribed agents exert macroscopic effects on subcortical nuclei of unknown relation to therapeutic response.

Abnormal functional connectivity of the striatum in first-episode drug-naive early-onset Schizophrenia

Abnormal brain network connectivity is strongly implicated in the pathogenesis of schizophrenia. The striatum, consisting of the caudate and putamen, is the major treatment target for antipsychotics, the primary treatments for schizophrenia; however, there are few studies on the functional connectivity (FC) of striatum in drug-naive early-onset schizophrenia (EOS) patients. We examined the FC values of the caudate nucleus and putamen with whole brain by resting-state functional magnetic resonance imaging (RS-fMRI) and the associations with indices of clinical severity. Patients demonstrated abnormal FC between subregions of the putamen and both the visual network (left middle occipital gyrus) and default mode network (bilateral anterior cingulate, left superior frontal, and right middle frontal gyri). Furthermore, FC between dorsorostral putamen and left superior frontal gyrus correlated with both positive symptom subscore and total score on the Positive and Negative Syndrome Scale (PANSS). These findings demonstrate abnormal FC between the striatum and other brain areas even in the early stages of schizophrenia, supporting neurodevelopmental disruption in disease etiology and expression.

Asphyxia at birth affects brain structure in patients on the schizophrenia-bipolar disorder spectrum and healthy participants

BACKGROUND

Uncertainty exists about what causes brain structure alterations associated with schizophrenia (SZ) and bipolar disorder (BD). Whether a history of asphyxia-related obstetric complication (ASP) - a common but harmful condition for neural tissue - contributes to variations in adult brain structure is unclear. We investigated ASP and its relationship to intracranial (ICV), global brain volumes and regional cortical and subcortical structures.

METHODS

A total of 311 patients on the SZ - BD spectrum and 218 healthy control (HC) participants underwent structural magnetic resonance imaging. They were evaluated for ASP using prospective information obtained from the Medical Birth Registry of Norway.

RESULTS

In all groups, ASP was related to smaller ICV, total brain, white and gray matter volumes and total surface area, but not to cortical thickness. Smaller cortical surface areas were found across frontal, parietal, occipital, temporal and insular regions. Smaller hippocampal, amygdala, thalamus, caudate and putamen volumes were reported for all ASP subgroups. ASP effects did not survive ICV correction, except in the caudate, which remained significantly smaller in both patient ASP subgroups, but not in the HC.

CONCLUSIONS

Since ASP was associated with smaller brain volumes in all groups, the genetic risk of developing a severe mental illness, alone, cannot easily explain the smaller ICV. Only the smaller caudate volumes of ASP patients specifically suggest that injury from ASP can be related to disease development. Our findings give support for the ICV as a marker of aberrant neurodevelopment and ASP in the etiology of brain development in BD and SZ.

Characteristics of Multimodal Brain Connectomics in Patients With Schizophrenia and the Unaffected First-Degree Relatives

OBJECTIVE

Increasing pieces of evidence suggest that abnormal brain connectivity plays an important role in the pathophysiology of schizophrenia. As an essential strategy in psychiatric neuroscience, the research of brain connectivity-based neuroimaging biomarkers has gained increasing attention. Most of previous studies focused on a single modality of the brain connectomics. Multimodal evidence will not only depict the full profile of the brain abnormalities of patients but also contribute to our understanding of the neurobiological mechanisms of this disease.

METHODS

In the current study, 99 schizophrenia patients, 69 sex- and education-matched healthy controls, and 42 unaffected first-degree relatives of patients were recruited and scanned. The brain was parcellated into 246 regions and multimodal network analyses were used to construct brain connectivity networks for each participant.

RESULTS

Using the brain connectomics from three modalities as the features, the multi-kernel support vector machine method yielded high discrimination accuracies for schizophrenia patients (94.86%) and for the first-degree relatives (95.33%) from healthy controls. Using an independent sample (49 patients and 122 healthy controls), we tested the model and achieved a classification accuracy of 64.57%. The convergent pattern within the basal ganglia and thalamus-cortex circuit exhibited high discriminative power during classification. Furthermore, substantial overlaps of the brain connectivity abnormality between patients and the unaffected first-degree relatives were observed compared to healthy controls.

CONCLUSION

The current findings demonstrate that decreased functional communications between the basal ganglia, thalamus, and the prefrontal cortex could serve as biomarkers and endophenotypes for schizophrenia.

Subcortical Brain Volume Abnormalities in Individuals With an At-risk Mental State

Previous structural magnetic resonance imaging studies of psychotic disorders have demonstrated volumetric alterations in subcortical (ie, the basal ganglia, thalamus) and temporolimbic structures, which are involved in high-order cognition and emotional regulation. However, it remains unclear whether individuals at high risk for psychotic disorders with minimal confounding effects of medication exhibit volumetric changes in these regions. This multicenter magnetic resonance imaging study assessed regional volumes of the thalamus, caudate, putamen, nucleus accumbens, globus pallidus, hippocampus, and amygdala, as well as lateral ventricular volume using FreeSurfer software in 107 individuals with an at-risk mental state (ARMS) (of whom 21 [19.6%] later developed psychosis during clinical follow-up [mean = 4.9 years, SD = 2.6 years]) and 104 age- and gender-matched healthy controls recruited at 4 different sites. ARMS individuals as a whole demonstrated significantly larger volumes for the left caudate and bilateral lateral ventricles as well as a smaller volume for the right accumbens compared with controls. In male subjects only, the left globus pallidus was significantly larger in ARMS individuals. The ARMS group was also characterized by left-greater-than-right asymmetries of the lateral ventricle and caudate nucleus. There was no significant difference in the regional volumes between ARMS groups with and without later psychosis onset. The present study suggested that significant volume expansion of the lateral ventricle, caudate, and globus pallidus, as well as volume reduction of the accumbens, in ARMS subjects, which could not be explained only by medication effects, might be related to general vulnerability to psychopathology.

Basal ganglia volumetric changes in psychotic spectrum disorders

BACKGROUND

Basal ganglia are particularly important for understanding the pathobiology of psychosis given their key roles in dopaminergic neurotransmission which are associated with psychotic symptoms and one of the target sites of antipsychotic drugs. Psychotic symptoms are prevalent in both schizophrenia (SZ) and bipolar disorder (BD). Although the components of basal ganglia are implicated in psychosis, comparative structural changes of components of the basal ganglia between SZ and BD are less clear after disentanglement of clinical effects of antipsychotic dose, duration and severity of illness.

METHODS

In this study, we examined the morphology of the basal ganglia in 326 subjects comprising of 45 patients of BD type I with psychotic symptoms, 97 first-episode SZ (FE-SZ) patients, 86 non-first-episode chronic SZ (NFE-SZ) patients, in comparison with 98 healthy controls (HC).

RESULTS

Results showed increased volumes in subregions of caudate, putamen, and pallidum in chronic SZ patients compared with HC after controlling for age, gender, and total intracranial volume. No change was found between FE-SZ patients, psychotic BD patients, and HC. Furthermore, hierarchical regressions showed that the dosage of antipsychotics had a significant contribution to basal ganglia volumetric enlargement in NFE-SZ after controlling for the effects of age, gender, total intracranial volume, age at illness onset, as well as illness duration and severity.

LIMITATIONS

Lack of information about the cumulative history of exposure to medication for all the three groups of patients is a major limitation in our study.

CONCLUSIONS

There are distinct basal ganglia structural changes in SZ and psychotic BD. Basal ganglia are enlarged in chronic SZ but not in FE-SZ and BD and this enlargement is significantly associated with antipsychotic dosage over and beyond the effects of illness duration and severity.

A diffusion weighted imaging study of basal ganglia in schizophrenia

OBJECTIVES

Several magnetic resonance imaging (MRI) studies provided evidence of selective brain abnormalities in schizophrenia, both in cortical and subcortical structures. Basal ganglia are of particular interest, given not only the high concentration of dopaminergic neurons and receptors, but also for their crucial role in cognitive functions, commonly impaired in schizophrenia. To date, very few studies explored basal ganglia using diffusion imaging, which is sensitive to microstructural organization in brain tissues. The aim of our study is to explore basal ganglia structures with diffusion imaging in a sizeable sample of patients affected by schizophrenia and healthy controls.

METHODS

We enrolled 52 subjects affected by schizophrenia according to DMS-IV-R criteria and 46 healthy controls. Diffusion weighted images were obtained using a 1.5 Tesla scanner and apparent diffusion coefficient (ADC) values were determined in axial and coronal sections at the level of basal ganglia.

RESULTS

Patients affected by schizophrenia showed a significantly higher ADC compared to healthy controls in the left anterior lenticular nucleus (F = 3.9, p = .05). A significant positive correlation between right anterior lenticular nucleus and psychotropic dosages was found (r = 0.4, p = .01).

CONCLUSIONS

Our study provides evidence of lenticular nucleus microstructure alterations in schizophrenia, potentially sustaining cognitive and motor deficits in schizophrenia. Key points The basal ganglia structures was explored with diffusion imaging in a sizeable sample of patients affected by schizophrenia and healthy controls. Patients affected by schizophrenia showed a significantly higher ADC compared to healthy controls in the left anterior lenticular nucleus. Our study provides evidence of lenticular nucleus microstructure alterations in schizophrenia, potentially sustaining cognitive and motor deficits in schizophrenia.

Correlation analysis between the morphometric characteristics of the head of nucleus caudatus and the intensity of psychotic manifestation in schizophrenia

Introduction: One of the significant functional disorders of the central nervous system in patients with schizophrenia is the increased activity of the mesolimbic dopaminergic system. By the nigrostriatal pathway, the caudate nucleus is closely related to other dopaminergic systems of the brain. Since the function of caudate nucleus relies on the action of Dopamine in the brain; the role of this anatomical structure in the pathogenesis of schizophrenia is not sufficiently clarified. The aim of this paper was to examine whether the caudate nucleus participates in the modulation of the intensity of psychotic manifestations in schizophrenia. Patients and Methods: The study included a total of thirty-one patients with schizophrenia. Diagnosis of the schizophrenia was based on the DSM-IV criterion (Diagnostic and Statistical Manual of Mental Disorders, fourth edition), and the intensity of psychotic manifestations was evaluated by using Brief Psychiatric Rating Scale (BPRS). The size of the caudate nucleus was determined on axial non-contrast CT images on the surface of the largest cross-section using AutoCAD 2007 digital morphometry. The statistical data were processed by the SPSS 16.0 program package. The statistical conclusions are presented on the basis of two-tail p < 0.05. Results: In this study, we have observed a negative correlation between the area as well as the perimeter of the left caudate nucleus head section and the intensity of the psychotic manifestations (area: regression coefficient B = -0.17, p = 0.050, perimeter: regression coefficient B = -0.010, p = 0.012). On the right hemisphere of the brain we observed only a negative correlation of the intensity of the psychotic manifestations from the perimeter of the head section of caudate nucleus (regression coefficient B = -0.013, p = 0.011). Conclusion: In our research we found that the higher intensity of psychotic manifestations in schizophrenia was accompanied with the smaller area and the perimeter of left caudate head as well as the smaller perimeter of the head of right caudate nucleus. The finding of the dependence of the intensity of psychotic manifestations on the perimeter of the right caudate head and not on its area speaks in favor of the caudate head surface deformations as one of the markers of intensity of psychotic manifestations in patients with schizophrenia

Elevated mRNA expression of CASPR3 in patients with schizophrenia

BACKGROUND

Recently, it was reported that antipsychotic treatment reverted Contactin Associated Protein-Like 3 (CASPR3, same as CNTNAP3) mRNA expressions in leukocytes of schizophrenia (SCZ) subjects to the same levels as healthy controls. CASPR3 was expressed in various regions of the mice brain (cortex, frontal lobes, corpus callosum, hippocampus, etc.). Thus, this study evaluated CASPR3 mRNA expression in SCZ subjects to find a new clue of schizophrenia pathogenesis.

METHODS

One hundred SCZ subjects and 100 age-matched controls were compared. Levels of CASPR3 mRNA in leukocytes were analysed with a quantitative real-time PCR method using TaqMan probes.

RESULTS

CASPR3 mRNA expression was significantly higher in leukocytes of SCZ subjects than controls. However, there were no significant correlations between expression level and any clinical parameters in 50 SCZ subjects.

CONCLUSION

Considering that CASPR3 is involved in building the brain neural network and autophagy in circulating leukocytes, abnormal CASPR3 expression in SCZ subjects may be associated with the pathogenesis of SCZ.

Gray matter volumes may predict the clinical response to paliperidone palmitate long-acting in acute psychosis: A pilot longitudinal neuroimaging study

In schizophrenia, paliperidone palmitate (PP) long acting injectable (LAI) has been reported to sustain plasma concentrations and improve clinical symptoms. Moreover, it has also been demonstrated the important role of total gray matter (GM) volumes in predicting the clinical outcome. However, no studies investigating the association between PP-LAI treatment and brain morphometry has been published so far. Therefore, the main aim of our 24 weeks prospective observational exploratory study was to investigate the relation between brain anatomy and clinical outcome in seven patients with acute psychosis treated with PP-LAI. At baseline and every month (from T0 to T6) patients were clinically evaluated with the Brief Psychiatric Rating Scale (BPRS). 3T Magnetic Resonance Imaging at baseline was acquired and total GM and intracranial volumes were extracted to explore their predictive values on BPRS scores. After 24 weeks of treatment with PP-LAI, patients showed statistically significant improvements in BPRS scores. Moreover, subjects with higher total GM volumes had a significantly higher BPRS improvement at 24 weeks compared to patients with lower total GM volumes. Our findings confirm the effectiveness of PP-LAI in treating acute psychosis and suggest that greater GM volumes predict drug response, potentially supporting a favorable prognosis.

Altered Basal Ganglia Network Integration in Schizophrenia

The basal ganglia involve in a range of functions that are disturbed in schizophrenia patients. This study decomposed the resting-state data of 28 schizophrenia patients and 31 healthy controls with spatial independent component analysis and identified increased functional integration in the bilateral caudate nucleus in schizophrenia patients. Further, the caudate nucleus in patients showed altered functional connection with the prefrontal area and cerebellum. These results identified the importance of basal ganglia in schizophrenia patients. Clinical Trial Registration: Chinese Clinical Trial Registry. Registration number ChiCTR-RCS-14004878.

Brain Structural Effects of Antipsychotic Treatment in Schizophrenia: A Systematic Review

The findings about the progressive brain changes in schizophrenia are controversial, and the potential confounding effect of antipsychotics on brain structure is still under debate. The goal of the current article was to review the existing longitudinal neuroimaging studies addressing the impact of antipsychotic drug treatment on brain changes in schizophrenia. A comprehensive search of PubMed was performed using combinations of key terms distributed into four blocks: "MRI", "longitudinal", "schizophrenia" and "antipsychotic". Studies were considered to be eligible for the review if they were original articles. Studies that examined only changes in brain density were excluded. A total of 41 MRI studies were identified and reviewed. Longitudinal MRI studies did not provide a consistent notion of the effects of antipsychotic treatment on the pattern of brain changes over time in schizophrenia. Overall, most of the included articles did not find a linear relationship between the degree of exposure and progressive brain changes. Further short- and longterm studies are warranted to a better understanding of the influence of antipsychotics in brain structural changes in schizophrenia and also to verify whether first and second generation antipsychotics may differentially affect brain morphometry.