Hippocampal volume deficits and shape deformities in young biological relatives of schizophrenia probands

Aberrant hippocampus and amygdala morphology associated with cognitive deficits in schizophrenia

Background

Working memory deficits are thought to be a primary disturbance in schizophrenia. We aimed to identify differences in morphology of the hippocampus and amygdala in patients with schizophrenia compared with healthy controls (HCs), and in patients who were either neuropsychologically near normal (NPNN) or neuropsychologically impaired (NPI). Morphological disturbances in the same subfields of the hippocampus and amygdala, but of greater magnitude in those with NPI, would strengthen evidence for the centrality of these limbic regions and working memory deficits in the pathogenesis of schizophrenia.

Methods

We acquired anatomical MRIs in 69 patients with schizophrenia (18 NPNN, 46 NPI) and 63 age-matched HC participants. We compared groups in hippocampus and amygdala surface morphologies and correlated morphological measures with clinical symptoms and working memory scores.

Results

Schizophrenia was associated with inward deformations of the head and tail of the hippocampus, protrusion of the hippocampal body, and widespread inward deformations of the amygdala. In the same regions where we detected the effects of schizophrenia, morphological measures correlated positively with the severity of symptoms and inversely with working memory performance. Patients with NPI displayed a similar pattern of anatomical abnormality compared to patients with NPNN.

Conclusion

Our findings indicate that anatomical abnormalities of the hippocampus relate to working memory performance and clinical symptoms in persons with schizophrenia. Moreover, NPNN and NPI patients may lie on a continuum of severity, both in terms of working memory abilities and altered brain structure, with NPI patients being more severe than NPNN patients in both domains.

Incomplete Hippocampal Inversion: A Neurodevelopmental Mechanism for Hippocampal Shape Deformation in Schizophrenia

BACKGROUND

Shape analyses of patients with schizophrenia have revealed bilateral deformations of the anterolateral hippocampus, primarily localized to the CA1 subfield. Incomplete hippocampal inversion (IHI), an anatomical variant of the human hippocampus resulting from an arrest during neurodevelopment, is more prevalent and severe in patients with schizophrenia. We hypothesized that IHI would affect the shape of the hippocampus and contribute to hippocampal shape differences in schizophrenia.

METHODS

We studied 199 patients with schizophrenia and 161 healthy control participants with structural magnetic resonance imaging to measure the prevalence and severity of IHI. High-fidelity hippocampal surface reconstructions were generated with the SPHARM-PDM toolkit. We used general linear models in SurfStat to test for group shape differences, the impact of IHI on hippocampal shape variation, and whether IHI contributes to hippocampal shape abnormalities in schizophrenia.

RESULTS

Not including IHI as a main effect in our between-group comparison replicated well-established hippocampal shape differences in patients with schizophrenia localized to the CA1 subfield in the anterolateral hippocampus. Shape differences were also observed near the uncus and hippocampal tail. IHI was associated with outward displacements of the dorsal and ventral surfaces of the hippocampus and inward displacements of the medial and lateral surfaces. Including IHI as a main effect in our between-group comparison eliminated the bilateral shape differences in the CA1 subfield. Shape differences in the uncus persisted after including IHI.

CONCLUSIONS

IHI impacts hippocampal shape. Our results suggest IHI as a neurodevelopmental mechanism for the well-known shape differences, particularly in the CA1 subfield, in schizophrenia.

Volume deficits in hippocampal subfields in unaffected relatives of schizophrenia patients with high genetic loading but without any psychiatric symptoms

BACKGROUND

Hippocampal volume changes have been reported in schizophrenia patients and their relatives and are proposed to contribute to the pathophysiology of schizophrenia. However, volume changes in the total hippocampus have not been consistently reported in relatives. The hippocampus consists of multiple subregions, and based on previous inconsistent results, subtle changes in specific subregions may occur in relatives. Here, we examined the subregion volumes in unaffected, high-functioning relatives (URs) without any psychiatric symptoms with high genetic loading with at least one first-degree relative diagnosed with schizophrenia and at least one or more other affected first- to third-degree relatives.

METHODS

We acquired structural magnetic resonance imaging data from 50 URs, 101 first-episode psychosis (FEP) patients, and 101 healthy controls (HCs). The cornu ammonis (CA), dentate gyrus, and subiculum subfields were automatically segmented using FreeSurfer 7.1.0. Each subregion volume was compared across the groups.

RESULTS

Compared with the HCs, the URs had a significant volume reduction in the left anterior CA (p = 0.039, Cohen's d = 0.480). In addition, the URs had a significantly larger right posterior subiculum (p = 0.001, Cohen's d = 0.541) than the FEP.

CONCLUSIONS

The smaller left anterior CA in the URs may reflect their genetic vulnerability to schizophrenia and supports previous findings suggesting specific vulnerability in this region. The volume differences between the URs and FEP patients in the right posterior subiculum may suggest that a smaller volume in this region may reflect a risk for schizophrenia other than genetic vulnerability.

Hippocampal Asymmetry of Regional Development and Structural Covariance in Preterm Neonates

Premature birth is associated with a high prevalence of neurodevelopmental impairments in surviving infants. The hippocampus is known to be critical for learning and memory, yet the putative effects of hippocampal dysfunction remain poorly understood in preterm neonates. In particular, while asymmetry of the hippocampus has been well noted both structurally and functionally, how preterm birth impairs hippocampal development and to what extent the hippocampus is asymmetrically impaired by preterm birth have not been well delineated. In this study, we compared volumetric growth and shape development in the hippocampal hemispheres and structural covariance (SC) between hippocampal vertices and cortical thickness in cerebral cortex regions between two groups. We found that premature infants had smaller volumes of the right hippocampi only. Lower thickness was observed in the hippocampal head in both hemispheres for preterm neonates compared with full-term peers, though preterm neonates exhibited an accelerated age-related change of hippocampal thickness in the left hippocampi. The SC between the left hippocampi and the limbic lobe of the premature infants was severely impaired compared with the term-born neonates. These findings suggested that the development of the hippocampus during the third trimester may be altered following early extrauterine exposure with a high degree of asymmetry.

Incomplete hippocampal inversion in schizophrenia: prevalence, severity, and impact on hippocampal structure

Incomplete hippocampal inversion (IHI) is an anatomical variant of the human brain resulting from an arrest in brain development, especially prevalent in the left hemisphere. We hypothesized that IHI is more common in schizophrenia and contributes to the well-known hippocampal structural differences. We studied 199 schizophrenia patients and 161 healthy control participants with 3 T MRI to establish IHI prevalence and the relationship of IHI with hippocampal volume and asymmetry. IHI was more prevalent (left hemisphere: 15% of healthy control participants, 27% of schizophrenia patients; right hemisphere: 4% of healthy control participants, 10% of schizophrenia patients) and more severe in schizophrenia patients compared to healthy control participants. Severe IHI cases were associated with a higher rate of automated segmentation failure. IHI contributed to smaller hippocampal volume and increased R > L volume asymmetry in schizophrenia. The increased prevalence and severity of IHI supports the neurodevelopmental model of schizophrenia. The impact of this developmental variant deserves further exploration in studies of the hippocampus in schizophrenia.

Automated, open-source segmentation of the Hippocampus and amygdala with the open Vanderbilt archive of the temporal lobe

Examining volumetric differences of the amygdala and anterior-posterior regions of the hippocampus is important for understanding cognition and clinical disorders. However, the gold standard manual segmentation of these structures is time and labor-intensive. Automated, accurate, and reproducible techniques to segment the hippocampus and amygdala are desirable. Here, we present a hierarchical approach to multi-atlas segmentation of the hippocampus head, body and tail and the amygdala based on atlases from 195 individuals. The Open Vanderbilt Archive of the temporal Lobe (OVAL) segmentation technique outperforms the commonly used FreeSurfer, FSL FIRST, and whole-brain multi-atlas segmentation approaches for the full hippocampus and amygdala and nears or exceeds inter-rater reproducibility for segmentation of the hippocampus head, body and tail. OVAL has been released in open-source and is freely available.

Reaction Time and Visual Memory in Connection with Alcohol Use in Schizophrenia and Schizoaffective Disorder

The purpose of this study was to explore the association between cognition and hazardous drinking and alcohol use disorder in schizophrenia and schizoaffective disorder. Cognition is more or less compromised in schizophrenia, and schizoaffective disorder and alcohol use might aggravate this phenomenon. The study population included 3362 individuals from Finland with diagnoses of schizophrenia or schizoaffective disorder. Hazardous drinking was screened with the AUDIT-C (Alcohol Use Disorders Identification Test for Consumption) screening tool. Alcohol use disorder (AUD) diagnoses were obtained from national registrar data. Participants performed two computerized tasks from the Cambridge Automated Neuropsychological Test Battery (CANTAB) on a tablet computer: The Five-Choice Serial Reaction Time Task (5-CSRTT) or the reaction time (RT) test and the Paired Associative Learning (PAL) test. The association between alcohol use and the RT and PAL tests was analyzed with log-linear regression and logistic regression, respectively. After adjustment for age, education, housing status, and the age at which the respondents had their first psychotic episodes, hazardous drinking was associated with a lower median RT in females and less variable RT in males, while AUD was associated with a poorer PAL test performance in terms of the total errors adjusted scores (TEASs) in females. Our findings of positive associations between alcohol and cognition in schizophrenia and schizoaffective disorder are unique.

Obstetric Complications and Brain Imaging in Schizophrenia: A Systematic Review

Schizophrenia is a complex disorder in which clinical symptomatology typically reflects underlying brain abnormalities that coalign with multiple physical health comorbidities. The pathogenesis of schizophrenia involves the interplay between genetic and environmental factors, with obstetric complications widely described as key players in elevating the risk of psychosis. In this regard, understanding the anatomical and functional alterations associated with obstetric complications may help to elucidate potential mechanisms through which birth complications could contribute to schizophrenia pathogenesis. We conducted a systematic review of the extant literature describing brain abnormalities and obstetric complications in patients with schizophrenia and related disorders in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. A total of 471 studies were retrieved and screened, and 33 studies met inclusion criteria for our review. Studies varied considerably in their methods, with 11 studies employing computed tomography, 1 using magnetic resonance spectroscopy, and 21 using magnetic resonance imaging. The scientific quality of the included studies was assessed and documented. Obstetric complications increase the risk of provoking brain abnormalities. These abnormalities range from decreased gray matter volume and abnormal brain-ventricle ratios to a reduction of volume in limbic regions-which relate to what is commonly observed in schizophrenia. However, current evidence from neuroimaging studies remains scant in relation to establishing obstetric complications as an independent risk factor for schizophrenia.

Positive psychotic symptoms are associated with divergent developmental trajectories of hippocampal volume during late adolescence in patients with 22q11DS

Low hippocampal volume is a consistent finding in schizophrenia and across the psychosis spectrum. However, there is a lack of studies investigating longitudinal hippocampal development and its relationship with psychotic symptoms. The 22q11.2 deletion syndrome (22q11DS) has proven to be a remarkable model for the prospective study of individuals at high risk of schizophrenia to unravel the pathophysiological processes predating the onset of psychosis. Repeated cerebral MRIs were acquired from 140 patients with 22q11DS (53 experiencing moderate-to-severe psychotic symptoms) and 135 healthy controls aged from 6 to 35 years and with up to 5 time points per participant. Hippocampal subfield analysis was conducted using FreeSurfer-v.6 and FIRST-FSL. Then, whole hippocampal and subfield volumes were compared across the groups. Relative to controls, patients with 22q11DS showed a remarkably lower volume of all subfields except for CA2/3. No divergent trajectories in hippocampal development were found. When comparing patients with 22q11DS exhibiting psychotic symptoms to those without psychosis, we detected a volume decrease during late adolescence, starting in CA1 and spreading to other subfields. Our findings suggested that hippocampal volume is consistently smaller in patients with 22q11DS. Moreover, we have demonstrated that patients with 22q11DS and psychotic symptoms undergo a further decrease in volume during adolescence, a vulnerable period for the emergence of psychosis. Interestingly, CA2/3, despite being affected in patients with psychotic symptoms, was the only area not reduced in patients with 22q11DS relative to controls, thus suggesting that its atrophy exclusively correlates with the presence of positive psychotic symptoms.

Volumetric and morphological characteristics of the hippocampus are associated with progression to schizophrenia in patients with first-episode psychosis

Background:

Abnormalities in the hippocampus have been implicated in the pathophysiology of psychosis. However, it is still unclear whether certain abnormalities are a pre-existing vulnerability factor, a sign of disease progression or a consequence of environmental factors. We hypothesized that first-episode psychosis patients who progress to schizophrenia after one year of follow up will display greater volumetric and morphological changes from the very beginning of the disorder.

Methods:

We studied the hippocampus of 41 patients with a first-episode psychosis and 41 matched healthy controls. MRI was performed at the time of the inclusion in the study. After one year, the whole sample was reevaluated and divided in two groups depending on the diagnoses (schizophrenia vs. non-schizophrenia).

Results:

Patients who progressed to schizophrenia showed a significantly smaller left hippocampus volume than control group and no-schizophrenia group (F = 3.54; df = 2, 77; P = 0.03). We also found significant differences in the morphology of the anterior hippocampus (CA1) of patients with first-episode psychosis who developed schizophrenia compared with patients who did not.

Conclusions:

These results are consistent with the assumption of hyperfunctioning dopaminergic cortico-subcortical circuits in schizophrenia, which might be related with an alteration of subcortical structures, such as the hippocampus, along the course of the disease. According with these results, hippocampus abnormalities may serve as a prognostic marker of clinical outcome in patients with a first-episode psychosis.

Variation in fourteen brain structure volumes in schizophrenia: A comprehensive meta-analysis of 246 studies

Despite hundreds of structural MRI studies documenting smaller brain volumes on average in schizophrenia compared to controls, little attention has been paid to group differences in the variability of brain volumes. Examination of variability may help interpret mean group differences in brain volumes and aid in better understanding the heterogeneity of schizophrenia. Variability in 246 MRI studies was meta-analyzed for 13 structures that have shown medium to large mean effect sizes (Cohen's d≥0.4): intracranial volume, total brain volume, lateral ventricles, third ventricle, total gray matter, frontal gray matter, prefrontal gray matter, temporal gray matter, superior temporal gyrus gray matter, planum temporale, hippocampus, fusiform gyrus, insula; and a control structure, caudate nucleus. No significant differences in variability in cortical/subcortical volumes were detected in schizophrenia relative to controls. In contrast, increased variability was found in schizophrenia compared to controls for intracranial and especially lateral and third ventricle volumes. These findings highlight the need for more attention to ventricles and detailed analyses of brain volume distributions to better elucidate the pathophysiology of schizophrenia.

Hippocampal volume and vasculature before and after exercise in treatment-resistant schizophrenia

BACKGROUND

Schizophrenia is associated with poor cognitive function and elevated cardiometabolic disease risk. These health concerns may exacerbate neurocognitive dysfunction associated with hippocampal abnormalities, particularly hippocampal volume reductions. Regular exercise is thought to improve symptom severity, reduce depression, and improve cognition in schizophrenia, and may trigger exercise-mediated hippocampal growth. The potential for the benefits of exercise for treatment-resistant schizophrenia patients has not been clearly assessed. This study aims to assess the effect of exercise on hippocampal plasticity and clinical outcomes in chronic schizophrenia.

METHODS

Seventeen DSM-IV criteria schizophrenia or schizoaffective disorder patients completed a customized moderate intensity 12-week aerobic or weight-bearing exercise program. Adherence rates were 83% ± 9.4%) with 70% of participants completing the entire exercise program. Concomitant neuroimaging, clinical and cognitive assessments were obtained at baseline and 12-weeks.

RESULTS

At follow-up, symptom severity scores (t(16) = -16.8, p. ≤ 0.0001) and social functioning (t(16) = 4.4, p. = 0.0004) improved. A trend for improved depression scores (t(16) = -2.0, p. = 0.06) with no change in anxiety, or extrapyramidal symptoms were seen. Hippocampal volume increased (t(16) = -2.54, p. = 0.02), specifically in the left CA-1 field (F(16) = -2.33, p. = 0.03). Hippocampal vascular volume was unchanged. Change in hippocampal volume and vascular volume was not significantly correlated with change in symptom severity or affect scores.

CONCLUSIONS

Adjunct exercise may accelerate symptom improvement in treatment-resistant psychosis patients. While the underlying mechanism remains unclear, these results indicate that chronic schizophrenia patients experience hippocampal plasticity in response to exercise.

STUDY REGISTRATION

Clinical Trials.govNCT01392885.

Impulsivity in unaffected adolescent biological relatives of schizophrenia patients

OBJECTIVE

Although schizophrenia is not a prototypic impulse-control disorder, patients report more impulsive behaviors, have higher rates of substance use, and show dysfunction in brain circuits that underlie impulsivity. We investigate impulsivity in unaffected biological relatives of schizophrenia patients to further understand the relationships between schizophrenia risk and impulse control during adolescence.

METHOD

Group differences in impulsivity (UPPS-P Impulsive Behavior Scale and delay discounting) were tested in 210 adolescents contrasting 39 first- and 53 second-degree biological relatives of schizophrenia patients, and 118 subjects with no schizophrenia family history (NSFH).

RESULTS

Compared to NSFH adolescents and to second-degree relatives, first-degree relatives of schizophrenia patients had increased impulsivity-related behaviors (higher UPPS-P Perseverance, Positive Urgency and Premeditation subscale scores) and greater preference for immediate rewards (smaller AUC and larger discounting constant). Second-degree relatives did not differ significantly from NSFH adolescents on self-report impulsive behaviors or on measures of impulsive decision-making. These group differences remained even after careful consideration of potential confounding factors.

CONCLUSION

Impulsivity is associated with schizophrenia risk, and its severity increases with greater familial relatedness to the schizophrenia proband. Additional studies are needed to understand the role impulsivity may play in mediating schizophrenia susceptibility during adolescence.

A QSAR model of Olanzapine derivatives as potential inhibitors for 5-HT2A Receptor

Schizophrenia is a complex, chronic mental disorder, affecting about 21 million people worldwide. It is characterized by symptoms, including distortions in thinking, perception, emotions, disorganized speech, sense of self and behavior. Recently, a numbers of marketed drugs for Schizophrenia are available against dopamine D2 and serotonin 5-HT2A receptors. Here, we docked Olanzapine derivatives (collected from literature) with 5-HT2A Receptor using the program AutoDock 4.2. The docked protein inhibitor complex structure was optimized using molecular dynamics simulation for 5ps with the CHARMM-22 force field using NAMD (NAnoscale Molecular Dynamics program) incorporated in visual molecular dynamics (VMD 1.9.2) and then evaluating the stability of complex structure by calculating RMSD values. NAMD is a parallel, object-oriented molecular dynamics code designed for high-performance simulation of large biomolecular systems. A quantitative structure activity relationship (QSAR) model was built using energy-based descriptors as independent variable and pKi value as dependent variable of eleven known Olanzapine derivatives with 5-HT2A Receptor, yielding correlation coefficient r2 of 0.63861. The predictive performance of QSAR model was assessed using different crossvalidation procedures. Our results suggest that a ligand-receptor binding interaction for 5-HT2A receptor using a QSAR model is promising approach to design more potent 5-HT2A receptor inhibitors prior to their synthesis.

Subcortical surface shape in youth at familial high risk for schizophrenia

Abnormalities in the subcortical brain regions that support cognitive functions have been reported in schizophrenia. Relatives of those with schizophrenia often present with psychosis-like traits (schizotypy) and similar cognition as those with schizophrenia. To evaluate the relationships between subcortical structure, schizotypy, and cognitive function, we assessed shape and volume of the hippocampus, amygdala and thalamus in untreated youth at familial high risk for schizophrenia (HRSZ). The sample consisted of 66 HRSZ and 69 age-matched healthy controls (HC). Subjects' cognitive functions and schizotypy were assessed, and T1-weighted brain MRI were analyzed using the FSL software FIRST. The right hippocampus and right amygdala showed significantly increased concavity (inward displacement) in HRSZ compared to HC. While regional subcortical shape displacements were significantly correlated with sustained attention and executive function scores in HC, fewer correlations were seen in HRSZ. This suggests a possible alteration of the local structure-function relationship in subcortical brain regions of HRSZ for these cognitive domains, which could be related to anomalous plasticity.

Transitive inference deficits in unaffected biological relatives of schizophrenia patients

Currently available treatments have limited efficacy in remediating cognitive impairment in schizophrenia. Efforts to facilitate cognition-enhancing drug discovery recommend the use of varied experimental cognitive paradigms (including relational memory) as assessment tools in clinical drug trials. Although relational memory deficits are increasingly being recognized as a reliable cognitive marker of schizophrenia, relational memory performance among unaffected biological relatives remains unknown. Therefore, we evaluated 73 adolescents or young adults (22 first- and 26 second-degree relatives of schizophrenia patients and 25 healthy controls (HC)) using a well-validated transitive inference (TI) experimental paradigm previously used to demonstrate relational memory impairment in schizophrenia. We found that TI deficits were associated with schizophrenia risk with first-degree relatives showing greater impairment than second-degree relatives. First-degree relatives had poorer TI performance with significantly lower accuracy and longer response times than HC when responding to TI probe pairs. Second-degree relatives had significantly quicker response times than first-degree relatives and were more similar to HC in TI performance. We further explored the relationships between TI performance and neurocognitive domains implicated in schizophrenia. Among HC, response times were inversely correlated with FSIQ, verbal learning, processing speed, linguistic abilities and working memory. In contrast, relatives (first-degree in particular) had a differing pattern of TI-neurocognition relationships, which suggest that different brain circuits may be used when relatives encode and retrieve relational memory. Our finding that unaffected biological relatives of schizophrenia patients have TI deficits lends further support for the use of relational memory construct in future pro-cognition drug studies.

Hippocampal Shape Abnormalities Predict Symptom Progression in Neuroleptic-Free Youth at Ultrahigh Risk for Psychosis

INTRODUCTION

Hippocampal abnormalities have been widely studied in schizophrenia spectrum populations including those at ultrahigh risk (UHR) for psychosis. There have been inconsistent findings concerning hippocampal morphology prior to and during the transition to psychosis, and little is known about how specific subregions are related to the symptom progression.

METHODS

A total of 80 participants (38 UHR and 42 healthy controls) underwent a 3T MRI scan, as well as structured clinical interviews. Shape analysis of hippocampi was conducted with FSL/FIRST vertex analysis to yield a localized measure of shape differences between groups. A subgroup of the sample (24 UHR and 24 controls) also returned for a 12-month clinical follow-up assessment.

RESULTS

The UHR group exhibited smaller hippocampal volumes bilaterally, and shape analysis revealed significant inversion in the left ventral posterior hippocampus in the UHR group. Greater inversion in this subregion was related to elevated symptomatology at baseline and increased positive symptoms, negative symptoms, and impaired tolerance to normal stress 12 months later. These results did not hold when left hippocampal volume was used as a predictor instead.

DISCUSSION

This represents the first study to use vertex analysis in a UHR sample and results suggest that abnormalities in hippocampal shape appear to reflect underlying pathogenic processes driving the progression of illness. These findings suggest that examining shape and volume may provide an important new perspective for our conception of brain alterations in the UHR period.

Subregional Hippocampal Morphology and Psychiatric Outcome in Adolescents Who Were Born Very Preterm and at Term

BACKGROUND

The hippocampus has been reported to be structurally and functionally altered as a sequel of very preterm birth (<33 weeks gestation), possibly due its vulnerability to hypoxic-ischemic damage in the neonatal period. We examined hippocampal volumes and subregional morphology in very preterm born individuals in mid- and late adolescence and their association with psychiatric outcome.

METHODS

Structural brain magnetic resonance images were acquired at two time points (baseline and follow-up) from 65 ex-preterm adolescents (mean age = 15.5 and 19.6 years) and 36 term-born controls (mean age=15.0 and 19.0 years). Hippocampal volumes and subregional morphometric differences were measured from manual tracings and with three-dimensional shape analysis. Psychiatric outcome was assessed with the Rutter Parents' Scale at baseline, the General Health Questionnaire at follow-up and the Peters Delusional Inventory at both time points.

RESULTS

In contrast to previous studies we did not find significant difference in the cross-sectional or longitudinal hippocampal volumes between individuals born preterm and controls, despite preterm individual having significantly smaller whole brain volumes. Shape analysis at baseline revealed subregional deformations in 28% of total bilateral hippocampal surface, reflecting atrophy, in ex-preterm individuals compared to controls, and in 22% at follow-up. In ex-preterm individuals, longitudinal changes in hippocampal shape accounted for 11% of the total surface, while in controls they reached 20%. In the whole sample (both groups) larger right hippocampal volume and bilateral anterior surface deformations at baseline were associated with delusional ideation scores at follow-up.

CONCLUSIONS

This study suggests a dynamic association between cross-sectional hippocampal volumes, longitudinal changes and surface deformations and psychosis proneness.

Heritability of subcortical and limbic brain volume and shape in multiplex-multigenerational families with schizophrenia

BACKGROUND

Brain abnormalities of subcortical and limbic nuclei are common in patients with schizophrenia, and variation in these structures is considered a putative endophenotype for the disorder. Multiplex-multigenerational families with schizophrenia provide an opportunity to investigate the impact of shared genetic ancestry, but these families have not been previously examined to study structural brain abnormalities. We estimate the heritability of subcortical and hippocampal brain volumes in multiplex-multigenerational families and the heritability of subregions using advanced shape analysis.

METHODS

The study comprised 439 participants from two sites who underwent 3T structural magnetic resonance imaging. The participants included 190 European-Americans from 32 multiplex-multigenerational families with schizophrenia and 249 healthy comparison subjects. Subcortical and hippocampal volume and shape were measured in 14 brain structures. Heritability was estimated for volume and shape.

RESULTS

Volume and shape were heritable in families. Estimates of heritability in subcortical and limbic volumes ranged from .45 in the right hippocampus to .84 in the left putamen. The shape of these structures was heritable (range, .40-.49), and specific subregional shape estimates of heritability tended to exceed heritability estimates of volume alone.

CONCLUSIONS

These results demonstrate that volume and shape of subcortical and limbic brain structures are potential endophenotypic markers in schizophrenia. The specificity obtained using shape analysis may improve selection of imaging phenotypes that better reflect the underlying neurobiology. Our findings can aid in the identification of specific genetic targets that affect brain structure and function in schizophrenia.

Hippocampal and amygdalar local structural differences in elderly patients with schizophrenia

OBJECTIVES

Morphological abnormalities have been reported for the hippocampi and amygdalae in young schizophrenia patients, but very little is known about the pattern of abnormalities in elderly schizophrenia patients. Here we investigated local structural differences in the hippocampi and amygdalae of elderly schizophrenia patients compared with healthy elderly subjects. We also related these differences to clinical symptom severity.

DESIGN

20 schizophrenia patients (mean age: 67.4 ± 6.2 years; Mini-Mental State Exam: 22.8 ± 4.4) and 20 healthy elderly subjects (70.3 ± 7.5 years; 29.0 ± 1.1) underwent high resolution magnetic resonance imaging of the brain. The Radial Atrophy Mapping technique was used to reconstruct the 3D shape of the amygdala and the hippocampus. Local differences in tissue reductions were computed between groups and permutation tests were run to correct for multiple comparisons, in statistical maps thresholded at p = 0.05.

RESULTS

Significant tissue reduction was observed bilaterally in the amygdala and hippocampus of schizophrenia patients. The basolateral-ventral-medial amygdalar nucleus showed the greatest involvement, with over 30% local tissue reduction. The centro-medial, cortical, and lateral nuclei were also atrophic in patients. The hippocampus showed significant tissue loss in the medio-caudal and antero-lateral aspects of CA1, and in medial section of its left head (pre- and para-subiculum). In the left amygdala and hippocampus, local tissue volumes were significantly correlated with negative symptoms.

CONCLUSIONS

Tissue loss and altered morphology were found in elderly schizophrenia patients. Tissue loss mapped to amygdalo-hippocampal subregions known to have bidirectional and specific connections with frontal cortical and limbic structures and was related to clinical severity.

Medial temporal lobe default mode functioning and hippocampal structure as vulnerability indicators for schizophrenia: a MRI study of non-psychotic adolescent first-degree relatives

BACKGROUND

Clues to the etiology and pathophysiology of schizophrenia can be examined in their first-degree relatives because they are genetically related to an ill family member, and have few confounds like medications. Brain abnormalities observed in young relatives are neurobiological indicators of vulnerability to illness. We examined the hypothesis that the hippocampus and parahippocampus are structurally abnormal and are related to default mode network (DMN) function and cognitive abnormalities in relatives of probands.

METHODS

Subjects were 27 non-psychotic, first-degree relatives of individuals diagnosed with schizophrenia, and 48 normal controls, ages 13 to 28, undergoing high-resolution magnetic resonance imaging (MRI) at 1.5 T. After structural scan acquisition a subset of subjects performed 2-back working memory (WM) and 0-back tasks during functional MRI (fMRI) alternating with rest. fMRI data were analyzed using SPM-8. Volumes of total cerebrum, hippocampus, and parahippocampal gyrus were measured using semi-automated morphometry.

RESULTS

Compared to controls, relatives had significantly smaller left hippocampi, without volumetric reduction in the parahippocampus. Relatives showed significantly less suppression of DMN activity in the left parahippocampal gyrus. Left hippocampal and posterior parahippocampal volumes were inversely and significantly associated with DMN processing (smaller volumes, less suppression) in relatives. Task suppression in parahippocampal gyrus significantly correlated with WM performance within the relatives.

CONCLUSION

Results support the hypothesis that the vulnerability to schizophrenia includes smaller hippocampi and DMN suppression deficits, and these are associated with poorer WM. Findings suggest a primary structural, neurodevelopmental, medial temporal lobe abnormality associated with altered DMN function independent of psychosis.

Hippocampus and amygdala volumes in children and young adults at high-risk of schizophrenia: research synthesis

BACKGROUND

Studies have reported hippocampal and amygdala volume abnormalities in schizophrenic patients. It is necessary to explore the potential for these structures as early disease markers in subjects at high risk (HR) of schizophrenia.

METHODS

We performed a review of 29 magnetic resonance imaging (MRI) studies measuring hippocampal and amygdala volumes in subjects at HR for schizophrenia. We reclassified subjects in 3 new HR categories: presence of only risk symptoms (psychotic moderate symptoms), presence of only risk factors (genetic, developmental or environmental), and presence of combined risk symptoms/factors.

RESULTS

Hippocampal volume reductions were detected in subjects with first episode (FE) of psychosis, in all young adults and in adolescents at HR of schizophrenia. The loss of tissue was mainly located in the posterior part of hippocampus and the right side seems more vulnerable in young adults with only risk symptoms. Instead, the anterior sector seems more involved in HR subjects with genetic risks. Abnormal amygdala volumes were found in FE subjects, in children with combined risk symptoms/factors and in older subjects using different inclusion criteria, but not in young adults.

CONCLUSION

Hippocampal and amygdala abnormalities may be present before schizophrenia onset. Further studies should be conducted to clarify whether these abnormalities are causally or effectually related to neurodevelopment. Shape analysis could clarify the impact of environmental, genetic, and developmental factors on the medial temporal structures during the evolution of this disease.

A review of neuroimaging studies of young relatives of individuals with schizophrenia: a developmental perspective from schizotaxia to schizophrenia

In an effort to identify the developing abnormalities preceding psychosis, Dr. Ming T. Tsuang and colleagues at Harvard expanded Meehl's concept of "schizotaxia," and examined brain structure and function in families affected by schizophrenia (SZ). Here, we systematically review genetic (familial) high-risk (HR) studies of SZ using magnetic resonance imaging (MRI), examine how findings inform models of SZ etiology, and suggest directions for future research. Neuroimaging studies of youth at HR for SZ through the age of 30 were identified through a MEDLINE (PubMed) search. There is substantial evidence of gray matter volume abnormalities in youth at HR compared to controls, with an accelerated volume reduction over time in association with symptoms and cognitive deficits. In structural neuroimaging studies, prefrontal cortex (PFC) alterations were the most consistently reported finding in HR. There was also consistent evidence of smaller hippocampal volume. In functional studies, hyperactivity of the right PFC during performance of diverse tasks with common executive demands was consistently reported. The only longitudinal fMRI study to date revealed increasing left middle temporal activity in association with the emergence of psychotic symptoms. There was preliminary evidence of cerebellar and default mode network alterations in association with symptoms. Brain abnormalities in structure, function and neurochemistry are observed in the premorbid period in youth at HR for SZ. Future research should focus on the genetic and environmental contributions to these alterations, determine how early they emerge, and determine whether they can be partially or fully remediated by innovative treatments.

Gray Matter Alterations in Schizophrenia High-Risk Youth and Early-Onset Schizophrenia: A Review of Structural MRI Findings

This article reviews the literature on structural magnetic resonance imaging findings in pediatric and young adult populations at clinical or genetic high-risk for schizophrenia and early-onset schizophrenia. The implications of this research are discussed for understanding the pathophysiology of schizophrenia and for early intervention strategies. The evidence linking brain structural changes in prepsychosis development and early-onset schizophrenia with disruptions of normal neurodevelopmental processes during childhood or adolescence is described. Future directions are outlined for research to address knowledge gaps regarding the neurobiological basis of brain structural abnormalities in schizophrenia and to improve the usefulness of these abnormalities for preventative interventions.

Amygdala-hippocampal shape and cortical thickness abnormalities in first-episode schizophrenia and mania

BACKGROUND

Abnormalities in cortical thickness and subcortical structures have been studied in schizophrenia but little is known about corresponding changes in mania and brain structural differences between these two psychiatric conditions, especially early in the stage of the illness. In this study we aimed to compare cortical thickness and shape of the amygdala-hippocampal complex in first-episode schizophrenia (FES) and mania (FEM). Method Structural magnetic resonance imaging (MRI) was performed on 28 FES patients, 28 FEM patients and 28 healthy control subjects who were matched for age, gender and handedness.

RESULTS

Overall, the shape of the amygdala was deformed in both patient groups, relative to controls. Compared to FEM patients, FES patients had significant inward shape deformation in the left hippocampal tail, right hippocampal body and a small region in the right amygdala. Cortical thinning was more widespread in FES patients, with significant differences found in the temporal brain regions when compared with FEM and controls.

CONCLUSIONS

Significant differences were observed between the two groups of patients with FES and FEM in terms of the hippocampal shape and cortical thickness in the temporal region, highlighting that distinguishable brain structural changes are present early in the course of schizophrenia and mania.

Hippocampal shape abnormalities of patients with childhood-onset schizophrenia and their unaffected siblings

OBJECTIVE

The hippocampus has been implicated in the pathogenesis of schizophrenia, and hippocampal volume deficits have been a consistently reported abnormality, but the subregional specificity of the deficits remains unknown. The authors explored the nature and developmental trajectory of subregional shape abnormalities of the hippocampus in patients with childhood-onset schizophrenia (COS), their healthy siblings, and healthy volunteers.

METHOD

Two hundred twenty-five anatomic brain magnetic resonance images were obtained from 103 patients with COS, 169 from their 79 healthy siblings, and 255 from 101 age- and sex-matched healthy volunteers (age range = 9-29 years). The hippocampus was segmented using FreeSurfer automated image analysis software, and hippocampal shape was evaluated by comparing subjects at more than 6,000 vertices on the left and right hippocampal surfaces. Longitudinal data were examined using mixed model regression analysis.

RESULTS

Patients with COS showed significant bilateral inward deformation in the anterior hippocampus. Healthy siblings also showed a trend for anterior inward deformation. However, the trajectory of shape change did not differ significantly between the groups. Inward deformations in the anterior hippocampus were positively related to positive symptom severity, whereas outward surface displacement was positively related to overall functioning.

CONCLUSION

This is the first and largest longitudinal three-way analysis of subregional hippocampal shape abnormalities in patients with COS and their healthy siblings compared with healthy controls. The anterior hippocampal abnormalities in COS suggest the pathophysiologic importance of this subregion in schizophrenia. The trend level and overlapping shape abnormalities in the healthy siblings suggest a more subtle, subregionally specific neuroanatomic endophenotype.

Hippocampal shape variations at term equivalent age in very preterm infants compared with term controls: perinatal predictors and functional significance at age 7

The hippocampus undergoes rapid growth and development in the perinatal months. Infants born very preterm (VPT) are vulnerable to hippocampal alterations, and can provide a model of disturbed early hippocampal development. Hippocampal shape alterations have previously been associated with memory impairment, but have never been investigated in infants. The aims of this study were to determine hippocampal shape differences between 184 VPT infants (<30 weeks' gestation or <1250 g at birth) and 32 full-term infants, effects of perinatal factors, and associations between infant hippocampal shape and volume, and 7 year verbal and visual memory (California Verbal Learning Test - Children's Version and Dot Locations). Infants underwent 1.5 T magnetic resonance imaging at term equivalent age. Hippocampi were segmented, and spherical harmonics-point distribution model shape analysis was undertaken. VPT infants' hippocampi were less infolded than full-term infants, being less curved toward the midline and less arched superior-inferiorly. Straighter hippocampi were associated with white matter injury and postnatal corticosteroid exposure. There were no significant associations between infant hippocampal shape and 7 year memory measures. However, larger infant hippocampal volumes were associated with better verbal memory scores. Altered hippocampal shape in VPT infants at term equivalent age may reflect delayed or disrupted development. This study provides further insight into early hippocampal development and the nature of hippocampal abnormalities in prematurity.

The effect of neurogranin on neural correlates of episodic memory encoding and retrieval

Neurogranin (NRGN) is the main postsynaptic protein regulating the availability of calmodulin-Ca(2+) in neurons. NRGN is expressed exclusively in the brain, particularly in dendritic spines and has been implicated in spatial learning and hippocampal plasticity. Genetic variation in rs12807809 in the NRGN gene has recently been confirmed to be associated with schizophrenia in a meta-analysis of genome-wide association studies: the T-allele was found to be genome-wide significantly associated with schizophrenia. Cognitive tests and personality questionnaires were administered in a large sample of healthy subjects. Brain activation was measured with functional magnetic resonance imaging (fMRI) during an episodic memory encoding and retrieval task in a subsample. All subjects were genotyped for NRGN rs12807809. There was no effect of genotype on personality or cognitive measures in the large sample. Homozygote carriers of the T-allele showed better performance in the retrieval task during fMRI. After controlling for memory performance, differential brain activation was evident in the anterior cingulate cortex for the encoding and posterior cingulate regions during retrieval. We could demonstrate that rs12807809 of NRGN is associated with differential neural functioning in the anterior and posterior cingulate. These areas are involved in episodic memory processes and have been implicated in the pathophysiology of schizophrenia in structural and functional imaging as well as postmortem studies.

The DTNBP1 (dysbindin-1) gene variant rs2619522 is associated with variation of hippocampal and prefrontal grey matter volumes in humans

DTNBP1 is one of the most established susceptibility genes for schizophrenia, and hippocampal volume reduction is one of the major neuropathological findings in this severe disorder. Consistent with these findings, the encoded protein dysbindin-1 has been shown to be diminished in glutamatergic hippocampal neurons in schizophrenic patients. The aim of this study was to investigate the effects of two single nucleotide polymorphisms of DTNBP1 on grey matter volumes in human subjects using voxel-based morphometry. Seventy-two subjects were included and genotyped with respect to two single nucleotide polymorphisms of DTNBP1 (rs2619522 and rs1018381). All participants underwent structural magnetic resonance imaging (MRI). MRI data were preprocessed and statistically analysed using standard procedures as implemented in SPM5 (Statistical Parametric Mapping), in particular the voxel-based morphometry (VBM) toolbox. We found significant effects of the DTNBP1 SNP rs2619522 bilaterally in the hippocampus as well as in the anterior middle frontal gyrus and the intraparietal cortex. Carriers of the G allele showed significantly higher grey matter volumes in these brain regions than T/T homozygotes. Compatible with previous findings on a role of dysbindin in hippocampal functions as well as in major psychoses, the present study provides first direct in vivo evidence that the DTNBP1 SNP rs2619522 is associated with variation of grey matter volumes bilaterally in the hippocampus.

Differences in subcortical structures in young adolescents at familial risk for schizophrenia: a preliminary study

Schizophrenia has been associated with reduced volumes of subcortical structures on magnetic resonance imaging (MRI), but the relation of these reductions to familial risk for the disorder is unclear. We investigated the effect of familial risk for schizophrenia on regional subcortical volumes during adolescence, a period marked by steep maturational changes in brain structure and the emergence of psychotic symptoms. A group of 26 non-help-seeking, first-degree relatives of patients with schizophrenia and 43 matched healthy comparisons, between 9 and 18 years of age, underwent MRI scanning and were rated for the presence of prodromal symptoms. Five subcortical regions-of-interest were tested for group differences and group by age interactions, as well as correlations with low-level prodromal symptoms in the familial risk group. Relative to comparisons, familial risk subjects demonstrated greater positive volume-age relationships in hippocampus, putamen, and globus pallidus. These results suggest that relatives of individuals with schizophrenia exhibit structural abnormalities in the subcortex as early as pre-adolescence, which may reflect altered neurodevelopment of these regions.

Stress abnormalities in individuals at risk for psychosis: a review of studies in subjects with familial risk or with "at risk" mental state

Increased sensitivity to stress is known to play an important role in the transition to first episode psychosis (FEP). Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, and, in general, an increased sensitivity to stress, have been hypothesised to be components of the vulnerability to psychosis, but whether these abnormalities are already present before the onset of psychosis has not yet been systematically reviewed. Here we have reviewed all studies examining psychological and biological markers of the stress response in the relatives of psychotic patients and in individuals at Ultra High Risk (UHR) for psychosis. In relatives, there is evidence of increased sensitivity to stress, as shown by increased emotional reactivity to daily life stress, increased adrenocorticotropic hormone (ACTH) in response to stress, increased pituitary volume and reduced hippocampal volume. However, evidence of increased cortisol levels is less consistent. On the other hand, subjects who experience attenuated psychotic symptoms show increased cortisol levels as well as increased pituitary and reduced hippocampal volumes. Moreover, this HPA axis hyperactivity seems to be even greater among those individuals who subsequently develop frank psychosis. In summary, an enhanced HPA axis response to stress appears to be part of the biological vulnerability to psychosis which is present prior to the onset of psychosis. A further increase in cortisol levels during the transition to FEP suggests the presence of an additive factor, possibly environmental, at this stage of the illness. Possible causes and consequences of HPA axis impairment in risk for psychosis are discussed.

Altered spatial learning, cortical plasticity and hippocampal anatomy in a neurodevelopmental model of schizophrenia-related endophenotypes

Adult rats exposed to the DNA-methylating agent methylazoxymethanol on embryonic day 17 show a pattern of neurobiological deficits that model some of the neuropathological and behavioral changes observed in schizophrenia. Although it is generally assumed that these changes reflect targeted disruption of embryonic neurogenesis, it is unknown whether these effects generalise to other antimitotic agents administered at different stages of development. In the present study, neurochemical, behavioral and electrophysiological techniques were used to determine whether exposure to the antimitotic agent Ara-C later in development recapitulates some of the changes observed in methylazoxymethanol (MAM)-treated animals and in patients with schizophrenia. Male rats exposed to Ara-C (30 mg/kg/day) at embryonic days 19.5 and 20.5 show reduced cell numbers and heterotopias in hippocampal CA1 and CA2/3 regions, respectively, as well as cell loss in the superficial layers of the pre- and infralimbic cortex. Birth date labeling with bromodeoxyuridine reveals that the cytoarchitectural changes in CA2/3 are a consequence rather that a direct result of disrupted cortical neurogenesis. Ara-C-treated rats possess elevated levels of cortical dopamine and DOPAC (3,4-didyhydroxypheylacetic acid) but no change in norepinephrine or serotonin. Ara-C-treated rats are impaired in their ability to learn the Morris water maze task and showed diminished synaptic plasticity in the hippocampocortical pathway. These data indicate that disruption of neurogenesis at embryonic days 19.5 and 20.5 constitutes a useful model for the comparative study of deficits observed in other gestational models and their relationship to cognitive changes observed in schizophrenia.

Medial temporal lobe structure and cognition in individuals with schizophrenia and in their non-psychotic siblings

Medial temporal lobe (MTL) structures play a central role in episodic memory. Prior studies suggest that individuals with schizophrenia have deficits in episodic memory as well as structural abnormalities of the medial temporal lobe (MTL). While correlations have been reported between MTL volume loss and episodic memory deficits in such individuals, it is not clear whether such correlations reflect the influence of the disease state or of underlying genetic influences that might contribute to risk. We used high resolution magnetic resonance imaging and probabilistic algorithms for image analysis to determine whether MTL structure, episodic memory performance and the relationship between the two differed among groups of 47 healthy control subjects, 50 control siblings, 39 schizophrenia subjects, and 33 siblings of schizophrenia subjects. High-dimensional large deformation brain mapping was used to obtain volume measures of the hippocampus. Cortical distance mapping was used to obtain volume and thickness measures of the parahippocampal gyrus (PHG) and its substructures: the entorhinal cortex (ERC), the perirhinal cortex (PRC), and the parahippocampal cortex (PHC). Neuropsychological data was used to establish an episodic memory domain score for each subject. Both schizophrenia subjects and their siblings displayed abnormalities in episodic memory performance. Siblings of individuals with schizophrenia, and to a lesser extent, individuals with schizophrenia themselves, displayed abnormalities in measures of MTL structure (volume loss or cortical thinning) as compared to control groups. Further, we observed correlations between structural measures and memory performance in both schizophrenia subjects and their siblings, but not in their respective control groups. These findings suggest that disease-specific genetic factors present in both patients and their relatives may be responsible for correlated abnormalities of MTL structure and memory impairment. The observed attenuated effect of such factors on MTL structure in individuals with schizophrenia may be due to non-genetic influences related to the development and progression of the disease on global brain structure and cognitive processing.

Regional specificity of thalamic volume deficits in male adolescents with early-onset psychosis

BACKGROUND

Thalamic volume deficits are associated with psychosis but it is unclear whether the volume reduction is uniformly distributed or whether it is more severe in particular thalamic regions.

AIMS

To quantify whole and regional thalamic volume in males with early-onset psychosis and healthy male controls.

METHOD

Brain scans were obtained for 80 adolescents: 46 individuals with early-onset psychosis with a duration of positive symptoms less than 6 months and 34 healthy controls. All participants were younger than 19 years. Total thalamic volumes were assessed using FreeSurfer and FSL-FIRST, group comparisons of regional thalamic volumes were studied with a surface-based approach.

RESULTS

Total thalamic volume was smaller in participants with early-onset psychosis relative to controls. Regional thalamic volume reduction was most significant in the right anterior mediodorsal area and pulvinar.

CONCLUSIONS

In males with minimally treated early-onset psychosis, thalamic volume deficits may be most pronounced in the anterior mediodorsal and posterior pulvinar regions, adding strength to findings from post-mortem studies in adults with psychosis.

Identification of the fetal hippocampus and fornix and role of 3-dimensional sonography

OBJECTIVES

The purposes of this study were to identify the fetal hippocampus and fornix using 3-dimensional sonography, to measure their curved length during pregnancy, and to describe a systematic method for volume data set analysis of the fetal hippocampus and fornix.

METHODS

Three-dimensional volumes of the fetal brain were acquired prospectively in 34 patients between 14 and 37 weeks' gestation. Volumes were acquired with trans-abdominal and transvaginal transducers. All volumes were analyzed offline by 2 examiners separately. The feasibility of identifying the fetal hippocampus and fornix was analyzed. The curved length of the hippocampus-fornix structure was measured on the right and left hemispheres.

RESULTS

The fetal hippocampus and fornix were identified bilaterally in 32 of 34 fetuses (94%) at gestational ages of 14 weeks 5 days to 37 weeks 1 day (mean, 23 weeks 3 days). In 1 fetus (3%), only one side was shown, and in another fetus (3%), both sides were obscured by acoustic shadows. A systematic approach for identification of the fetal hippocampus is described. Linear growth of the fetal hippocampus and fornix was shown during pregnancy and was correlated with both the gestational week and the head circumference (R = 0.71 and 0.74, respectively; P = .01). The length of the hippocampus and fornix did not differ between the left and the right hemispheres (P = .598).

CONCLUSIONS

The fetal hippocampus and fornix can be identified by a systematic analysis of 3-dimensional data set volumes. The normal hippocampus and fornix show linear growth throughout pregnancy.

Magnetic resonance spectroscopy of limbic structures displays metabolite differences in young unaffected relatives of schizophrenia probands

Imaging studies of schizophrenia patients showed fronto-temporal brain volume deficits, while magnetic resonance spectroscopy (MRS) studies of patients and unaffected biological relatives have found a decrement of the neuronal marker N-acetyl-aspartate (NAA) in the hippocampus and frontal lobes, and increased choline-containing phospholipids. Using a 3T MR scanner, we determined the metabolite profile within limbic regions (anterior cingulate cortex (ACC) and left hippocampus) of 36 unaffected, adolescent/young adult relatives of schizophrenia probands (first-degree=16, second-degree=20) and 25 healthy controls with no family history of schizophrenia. Significant main effects of group were found on NAA/Cho ratios for both the left hippocampus (F = 6.11, p ≤ 0.02) and ACC (F = 4.89, p ≤ 0.03) as well as for the left hippocampus Cho/Cr ratio (F = 5.55, p ≤ 0.02). Compared to age and sex matched healthy controls without a family history of schizophrenia, first-degree relatives of probands had greater MRS metabolite deviations than second-degree relatives. Greater familial proximity to the schizophrenia proband (or higher schizophrenia susceptibility) among biological relatives was associated with stepwise lowering of NAA/Cho and elevations in Cho/Cr ratios. The observed limbic metabolite changes among young, nonpsychotic biological relatives are likely related to shared genetic vulnerability factors, and may assist in the early identification of schizophrenia for primary and secondary prevention.

Putative structural neuroimaging endophenotypes in schizophrenia: a comprehensive review of the current evidence

The genetic contribution to schizophrenia etiopathogenesis is underscored by the fact that the best predictor of developing schizophrenia is having an affected first-degree relative, which increases lifetime risk by tenfold, as well as the observation that when both parents are affected, the risk of schizophrenia increases to approximately 50%, compared with 1% in the general population. The search to elucidate the complex genetic architecture of schizophrenia has employed various approaches, including twin and family studies to examine co-aggregation of brain abnormalities, studies on genetic linkage and studies using genome-wide association to identify genetic variations associated with schizophrenia. ‘Endophenotypes’, or ‘intermediate phenotypes’, are potentially narrower constructs of genetic risk. Hypothetically, they are intermediate in the pathway between genetic variation and clinical phenotypes and can supposedly be implemented to assist in the identification of genetic diathesis for schizophrenia and, possibly, in redefining clinical phenomenology.

Are we studying and treating schizophrenia correctly?

New findings are rapidly revealing an increasingly detailed image of neural- and molecular-level dysfunction in schizophrenia, distributed throughout interconnected cortico-striato-pallido-thalamic circuitry. Some disturbances appear to reflect failures of early brain maturation, that become codified into dysfunctional circuit properties, resulting in a substantial loss of, or failure to develop, both cells and/or appropriate connectivity across widely dispersed brain regions. These circuit disturbances are variable across individuals with schizophrenia, perhaps reflecting the interaction of multiple different risk genes and epigenetic events. Given these complex and variable hard-wired circuit disturbances, it is worth considering how new and emerging findings can be integrated into actionable treatment models. This paper suggests that future efforts towards developing more effective therapeutic approaches for the schizophrenias should diverge from prevailing models in genetics and molecular neuroscience, and focus instead on a more practical three-part treatment strategy: 1) systematic rehabilitative psychotherapies designed to engage healthy neural systems to compensate for and replace dysfunctional higher circuit elements, used in concert with 2) medications that specifically target cognitive mechanisms engaged by these rehabilitative psychotherapies, and 3) antipsychotic medications that target nodal or convergent circuit points within the limbic-motor interface, to constrain the scope and severity of psychotic exacerbations and thereby facilitate engagement in cognitive rehabilitation. The use of targeted cognitive rehabilitative psychotherapy plus synergistic medication has both common sense and time-tested efficacy with numerous other neuropsychiatric disorders.

Hippocampal volume development in healthy siblings of childhood-onset schizophrenia patients

OBJECTIVE

Previous anatomic studies have established a reduction in hippocampal volume in schizophrenia, but few have investigated the progressive course of these changes and whether they are trait markers. In the present study, the authors examined hippocampal volumes in relation to age for patients with childhood-onset schizophrenia, their nonpsychotic healthy siblings, and healthy comparison subjects.

METHOD

Anatomic brain magnetic resonance scans were obtained in childhood-onset schizophrenia probands (N=89, 198 scans), their nonpsychotic full siblings (N=78, 172 scans), and matched healthy comparison subjects (N=79, 198 scans) between the ages of 10 and 29 years. Total, left, and right hippocampal volumes were measured using FreeSurfer software and analyzed using a linear mixed-model regression covarying for sex and intracranial volume.

RESULTS

Childhood-onset schizophrenia probands had a fixed reduction in hippocampal volumes (total, left, and right) relative to both nonpsychotic siblings and healthy comparison subjects, whereas there were no significant volumetric or trajectory differences between nonpsychotic siblings and healthy comparison subjects.

CONCLUSIONS

Fixed hippocampal volume loss seen in childhood-onset schizophrenia, which is not shared by healthy siblings, appears to be related to the illness. Decreased hippocampal volume is not strongly genetically related but represents an important intermediate disease phenotype.

Statistical analysis of relative pose information of subcortical nuclei: application on ADNI data

Many brain morphometry studies have been performed in order to characterize the brain atrophy pattern of Alzheimer's disease (AD). The earliest studies focused on the volume of particular brain structures, such as hippocampus and entorhinal cortex. Even though volumetry is a powerful, robust and intuitive technique that has yielded a wealth of findings, more complex shape descriptors have been used to perform statistical shape analysis of particular brain structures. However, in shape analysis studies of brain structures the information of the relative pose between neighbor structures is typically disregarded. This work presents a framework to analyse pose information including the following approaches: similarity transformations with either pseudo-Riemannian or left-invariant Riemannian metric, and centered transformations with a bi-invariant Riemannian metric. As an illustration, an analysis of covariance (ANCOVA) and a discrimination analysis were performed on Alzheimer's Disease Neuroimaging Initiative (ADNI) data.

Structural pathology underlying neuroendocrine dysfunction in schizophrenia

Polydipsic hyponatremic schizophrenic (PHS) patients exhibit altered neuroendocrine activity that has been linked to their life-threatening water imbalance, as well as to impaired function and reduced volume of the anterior hippocampus. Polydipsic patients without hyponatremia (polydipsic normonatremic schizophrenics: PNS) exhibit similar, albeit less marked, changes in neuroendocrine activity and anterior hippocampal function, but not reduced anterior hippocampal volume. Indeed, reduced anterior hippocampal volume is seen in patients with normal water balance (nonpolydipsic normonatremic schizophrenics: NNS) whose neuroendocrine activity and anterior hippocampal function differ markedly from those with polydipsia. In an effort to reconcile these findings we measured hippocampal, amygdala and 3rd ventricle shapes in 26 schizophrenic patients (10 PNS, 7 PHS, 9 NNS) and 12 healthy controls matched for age and gender. Bilateral inward deformations were localized to the anterior lateral hippocampal surface (part of a neurocircuit which modulates neuroendocrine responses to psychological stimuli) in PHS and to a lesser extent in PNS, while deformations in NNS were restricted to the medial surface. Proportional deformations of the right medial amygdala, a key segment of this neurocircuit, were seen in both polydipsic groups, and correlated with the volume of the 3rd ventricle, which lies adjacent to the neuroendocrine nuclei. Finally, these structural findings were most marked in those with impaired hippocampal-mediated stress responses. These results reconcile previously conflicting data, and support the view that anterior lateral hippocampal pathology disrupts neuroendocrine function in polydipsic patients with and without hyponatremia. The relationship of these findings to the underlying mental illness remains to be established.

Integrative circuit models and their implications for the pathophysiologies and treatments of the schizophrenias

A preponderance of evidence indicates that the heterogeneous group of schizophrenias is accompanied by disturbances in neural elements distributed throughout multiple levels of interconnected cortico-striato-pallido-thalamic circuitry. These disturbances include a substantial loss of, or failure to develop, both cells and/or appropriate cellular connections in regions that include at least portions of the hippocampus, parahippocampal gyrus, entorhinal cortex, amygdala, prefrontal and anterior cingulate cortex, superior and transverse temporal gyri, and mediodorsal, anterior, and pulvinar nuclei of the thalamus; they appear to reflect failures of early brain maturation, that become codified into dysfunctional circuit properties, that in the opinion of this author cannot be "undone" or even predictably remediated in any physiological manner by existing pharmacotherapies. These circuit disturbances are variable across individuals with schizophrenia, perhaps reflecting the interaction of multiple different risk genes and multiple different epigenetic events. Evidence for these complex circuit disturbances has significant implications for many areas of schizophrenia research, and for future efforts toward developing more effective therapeutic approaches for this group of disorders. The conclusion of this chapter is that such future efforts should focus on further developing and refining medications that target nodal or convergent circuit points within the limbic-motor interface, with the goal of constraining the scope and severity of psychotic exacerbations, to be used in concert with systematic rehabilitative psychotherapies designed to engage healthy neural systems to compensate for and replace dysfunctional higher circuit elements. This strategy should be applied in both preventative and treatment settings, and disseminated for community delivery via an evidence-based manualized format. In contrast to alternative treatment strategies that range from complex polypharmacy to gene therapies to psychosurgical interventions, the use of combined medication plus targeted cognitive and behavioral psychotherapy has both common sense and time-tested documented efficacy with numerous other neuropsychiatric disorders.

QSAR-CoMSIA applied to antipsychotic drugs with their dopamine D2 and serotonine 5HT2A membrane receptors

Antipsychotic drugs are psychiatric medication primarily used to manage psychosis (e.g., delusions or hallucinations), particularly in schizophrenia and bipolar disorder. First and second generations of antipshychotics tend to block receptors in the brain's dopamine pathways, but antipsychotic drugs encompass a wide range of receptor targets. The inhibition constant, Ki, at the level of membrane receptors is a major determinant of their pharmacokinetic behavior and, consequently, it can affect their antipsychotic activity. Here, predicted inhibition constants, Ki for 71 antipsychotics, already approved for clinical treatment, as well as representative new chemical structures which exhibit antipsychotic activity, were evaluated using 3D-QSAR-CoMSIA models. Significant values of the cross-validated correlation q2 (higher than 0.70) and the fitted correlation r2 (higher than 0.80) revealed that these models have reasonable power to predict the biological affinity of the 15 new risperidone and 12 new olanzapine derivatives in interactions with dopamine D2 and serotonin 5HT2A receptors; these compounds are suggested for further studies.

Fully automated analysis using BRAINS: AutoWorkup

The BRAINS (Brain Research: Analysis of Images, Networks, and Systems) image analysis software has been in use, and in constant development, for over 20 years. The original neuroimage analysis pipeline using BRAINS was designed as a semiautomated procedure to measure volumes of the cerebral lobes and subcortical structures, requiring manual intervention at several stages in the process. Through use of advanced image processing algorithms the need for manual intervention at stages of image realignment, tissue sampling, and mask editing have been eliminated. In addition, inhomogeneity correction, intensity normalization, and mask cleaning routines have been added to improve the accuracy and consistency of the results. The fully automated method, AutoWorkup, is shown in this study to be more reliable (ICC ≥ 0.96, Jaccard index ≥ 0.80, and Dice index ≥ 0.89 for all tissues in all regions) than the average of 18 manual raters. On a set of 1130 good quality scans, the failure rate for correct realignment was 1.1%, and manual editing of the brain mask was required on 4% of the scans. In other tests, AutoWorkup is shown to produce measures that are reliable for data acquired across scanners, scanner vendors, and across sequences. Application of AutoWorkup for the analysis of data from the 32-site, multivendor PREDICT-HD study yield estimates of reliability to be greater than or equal to 0.90 for all tissues and regions.

Staging perspectives in neurodevelopmental aspects of neuropsychiatry: agents, phases and ages at expression

Neurodevelopmental risk factors have assumed a critical role in prevailing notions concerning the etiopathogenesis of neuropsychiatric disorders. Staging, diagnostic elements at which phase of disease is determined, provides a means of conceptualizing the degree and extent of factors affecting brain development trajectories, but is concurrently specified through the particular interactions of genes and environment unique to each individual case. For present purposes, staging perspectives in neurodevelopmental aspects of the disease processes are considered from conditions giving rise to neurodevelopmental staging in affective states, adolescence, dopamine disease states, and autism spectrum disorders. Three major aspects influencing the eventual course of individual developmental trajectories appear to possess an essential determinant influence upon outcome: (i) the type of agent that interferes with brain development, whether chemical, immune system activating or absent (anoxia/hypoxia), (ii) the phase of brain development at which the agent exerts disruption, whether prenatal, postnatal, or adolescent, and (iii) the age of expression of structural and functional abnormalities. Clinical staging may be assumed at any or each developmental phase. The present perspective offers both a challenge to bring further order to diagnosis, intervention, and prognosis and a statement regarding the extreme complexities and interwoven intricacies of epigenetic factors, biomarkers, and neurobehavioral entities that aggravate currents notions of the neuropsychiatric disorders.