Volumetric evaluation of the thalamus in schizophrenic male patients using magnetic resonance imaging

Reduced neural connectivity in the caudate anterior head predicts hallucination severity in schizophrenia

BACKGROUND

Caudate functional abnormalities have been identified as one critical neural substrate underlying sensory gating impairments that lead to auditory phantom hallucinations in both patients with schizophrenia (SZ) and tinnitus, characterized by the perception of internally generated sounds in the absence of external environmental auditory stimuli. In this study, we tested the hypothesis as to whether functional connectivity abnormalities in distinct caudate subdivisions implicated in sensory gating and auditory phantom percepts in tinnitus, which are currently being localized for neuromodulation targeting using deep brain stimulation techniques, would be associated with auditory phantom hallucination severity in SZ.

METHODS

Twenty five SZ and twenty eight demographically-matched healthy control (HC) participants, completed this fMRI resting-state study and clinical assessments.

RESULTS

Between-group seed-to-voxel analyses revealed only one region, the caudate anterior head, which showed reduced functional connectivity with the thalamus that survived whole-brain multiple comparison corrections. Importantly, connectivity between the caudate anterior head with thalamus negatively correlated with hallucination severity.

CONCLUSIONS

In the present study, we deliver the first evidence of caudate subdivision specificity for the neural pathophysiology underlying hallucinations in schizophrenia within a sensory gating framework that has been developed for auditory phantoms in patients with tinnitus. Our findings provide transdiagnostic convergent evidence for the role of the caudate in the gating of auditory phantom hallucinations, observed across patients with SZ and tinnitus by specifying the anterior caudate division is key to mediation of hallucinations, and creating a path towards personalized treatment approaches to arrest auditory phantom hallucinations from reaching perceptual awareness.

Cortical Thickness of the Orbitofrontal Cortex in Patients with Alcohol Use Disorder

Aims: In the present study, it was hypothesised that compared to healthy control subjects, significant differences in the cortical thickness of the orbitofrontal cortex (OFC) region of the brain, which is relevant to both impulsivity and decision making, would be identified. Methods: The subject groups included in the study were composed of 15 individuals who met the criteria for alcohol use disorder, according to the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM 5) diagnostic criteria based on the Structured Clinical Interview for DSM 5 (SCID), and were admitted to the Firat University School of Medicine Department of Psychiatry or were hospitalised, and 17 healthy control comparisons were made. The volumes of and cortical thickness of the OFC were measured in the subjects. Results: It was found that patients with alcohol use disorder had reduced volumes of the OFC bilaterally and a thinner cortical thickness of the same region bilaterally compared to those of the healthy control comparisons. Conclusions: Consequently, it is suggested that the OFC region of the brain appears to be statistically significantly smaller in patients with alcohol use disorder, both in terms of cortical thickness and volume, compared to healthy controls. Future research should focus on the status of these relationships longitudinally and should assess the causality of the association with the treatment response.

Structural covariance networks in schizophrenia: A systematic review Part I

BACKGROUND

Schizophrenia is proposed as a disorder of dysconnectivity. However, examination of complexities of dysconnectivity has been challenging. Structural covariance networks (SCN) provide important insights into the nature of dysconnectivity. This systematic review examines the SCN studies that employed statistical approaches to elucidate covariation of regional morphometric variations.

METHODS

A systematic search of literature was conducted for peer-reviewed publications using different keywords and keyword combinations for schizophrenia. Fifty-two studies met the criteria.

RESULTS

Early SCN studies began using correlational structure of selected regions. Over the last 3 decades, methodological approaches have grown increasingly sophisticated from examining selected brain regions using correlation tests on small sample sizes to recent approaches that use advanced statistical methods to examine covariance structure of whole-brain parcellations on larger samples. Although the results are not fully consistent across all studies, a pattern of fronto-temporal, fronto-parietal and fronto-thalamic covariation is reported. Attempts to associate SCN alterations with functional connectivity, to differentiate between disease-related and neurodevelopment-related morphometric changes, and to develop "causality-based" models are being reported. Clinical correlation with outcome, psychotic symptoms, neurocognitive and social cognitive performance are also reported.

CONCLUSIONS

Application of advanced statistical methods are beginning to provide insights into interesting patterns of regional covariance including correlations with clinical and cognitive data. Although these findings appear similar to morphometric studies, SCNs have the advantage of highlighting topology of these regions and their relationship to the disease and associated variables. Further studies are needed to investigate neurobiological underpinnings of shared covariance, and causal links to clinical domains.

Biomarker Identification Through Integrating fMRI and Epigenetics

OBJECTIVE

Integration of multiple datasets is a hot topic in many fields. When studying complex mental disorders, great effort has been dedicated to fusing genetic and brain imaging data. However, an increasing number of studies have pointed out the importance of epigenetic factors in the cause of psychiatric diseases. In this study, we endeavor to fill the gap by combining epigenetics (e.g., DNA methylation) with imaging data (e.g., fMRI) to identify biomarkers for schizophrenia (SZ).

METHODS

We propose to combine linear regression with canonical correlation analysis (CCA) in a relaxed yet coupled manner to extract discriminative features for SZ that are co-expressed in the fMRI and DNA methylation data.

RESULT

After validation through simulations, we applied our method to real imaging epigenetics data of 184 subjects from the Mental Illness and Neuroscience Discovery Clinical Imaging Consortium. After significance test, we identified 14 brain regions and 44 cytosine-phosphate-guanine(CpG) sites. Average classification accuracy is [Formula: see text]. By linking the CpG sites to genes, we identified pathways Guanosine ribonucleotides de novo biosynthesis and Guanosine nucleotides de novo biosynthesis, and a GO term Perikaryon.

CONCLUSION

This imaging epigenetics study has identified both brain regions and genes that are associated with neuron development and memory processing. These biomarkers contribute to a good understanding of the mechanism underlying SZ but are overlooked by previous imaging genetics studies.

SIGNIFICANCE

Our study sheds light on the understanding and diagnosis of SZ with a imaging epigenetics approach, which is demonstrated to be effective in extracting novel biomarkers associated with SZ.

Is formal thought disorder in schizophrenia related to structural and functional aberrations in the language network? A systematic review of neuroimaging findings

Formal thought disorder (FTD) is a core feature of schizophrenia, a marker of illness severity and a predictor of outcome. The underlying neural mechanisms are still a matter of debate. This study aimed at 1) reviewing the literature on the neural correlates of FTD in schizophrenia, and 2) testing the hypothesis that FTD correlates with structural and functional aberrations in the language network. Medline, PsychInfo, and Embase were searched for neuroimaging studies, which applied a clinical measure to assess FTD in adults with schizophrenia and were published in English or German in peer-reviewed journals until December 2016. Of 412 articles identified, 61 studies were included in the review. Volumetric studies reported bilateral grey matter deficits (L > R) to be associated with FTD in the inferior frontal gyrus, the superior temporal gyrus and the inferior parietal lobe. The same regions showed hyperactivity in resting state functional magnetic resonance imaging (fMRI) studies and both hyper- and hypoactivity in fMRI studies that employed semantic processing or free speech production tasks. Diffusion tensor imaging studies demonstrated white matter aberrations in fibre tracts that connect the frontal and temporo-parietal regions. FTD in schizophrenia was found to be associated with structural and functional aberrations in the language network. However, there are studies that did not find an association between FTD and neural aberrations of the language network and regions not included in the language network have been associated with FTD. Thus, future research is needed to clarify the specificity of the language network for FTD in schizophrenia.

Orbito-frontal cortex and thalamus volumes in the patients with obsessive-compulsive disorder before and after cognitive behavioral therapy

Background The effect of a variety of treatment modalities including psychopharmacological and cognitive behavioral therapy on the brain volumes and neurochemicals have not been investigated enough in the patients with obsessive-compulsive disorder. Therefore, in the present study, we aimed to investigate the effect of cognitive behavioral therapy on the volumes of the orbito-frontal cortex and thalamus regions which seem to be abnormal in the patients with obsessive-compulsive disorder. We hypothesized that there would be change in the volumes of the orbito-frontal cortex and thalamus. Methods Twelve patients with obsessive-compulsive disorder and same number of healthy controls were included into the study. At the beginning of the study, the volumes of the orbito-frontal cortex and thalamus were compared by using magnetic resonance imaging. In addition, volumes of these regions were measured before and after the cognitive behavioral therapy treatment in the patient group. Results The patients with obsessive-compulsive disorder had greater left and right thalamus volumes and smaller left and right orbito-frontal cortex volumes compared to those of healthy control subjects at the beginning of the study. When we compared baseline volumes of the patients with posttreatment ones, we detected that thalamus volumes significantly decreased throughout the period for both sides and that the orbito-frontal cortex volumes significantly increased throughout the period for only left side. Conclusions In summary, we found that cognitive behavioral therapy might volumetrically affect the key brain regions involved in the neuroanatomy of obsessive-compulsive disorder. However, future studies with larger sample are required.

Pituitary gland volumes in patients with obsessive-compulsive disorder before and after cognitive-behavioral therapy

OBJECTIVE

The beneficial effects of psychopharmacological and cognitive behavioral therapy (CBT) on the brain are not well understood. In a previous study, we found smaller pituitary volumes in patients with obsessive-compulsive disorder (OCD). The purpose of this study was to examine the effect of CBT on pituitary gland volume.

METHODS

A total of 81 patients with various anxiety disorders and the same number of healthy controls underwent magnetic resonance imaging, and their pituitary gland volumes were compared at baseline. Pituitary gland volumes were also measured before and after CBT in the patient group.

RESULTS

OCD patients had smaller pituitary gland volumes at baseline than healthy controls (0.54±0.29 cm3 for OCD patients vs. 0.82±0.30 cm3 for healthy controls; p < 0.001). We found no significant changes in OCD patient pituitary gland volume after the 16-week treatment period, with mean pre- and post-treatment values of 0.54±0.29 cm3 and 0.56±0.32 cm3, respectively (p > 0.05).

CONCLUSION

Our results indicate an absence of post-CBT volumetric changes in the pituitary gland of OCD patients.

Orbito-frontal cortex and thalamus volumes in obsessive-compulsive disorder before and after pharmacotherapy

In the present study, we focused on the key brain regions, OFC and thalamus, to investigate the roles of antiobsessional agents on volume changes of these brain regions after 12 weeks of anti-obsessional treatment in patients with obsessive-compulsive disorder (OCD). Fourteen patients with OCD and the same number of healthy controls were included in the study. At baseline, the volumes of the OFC and thalamus were compared by using magnetic resonance imaging (MRI) between groups. The volumes of OFC and thalamus were evaluated before and after the anti-obsessional drug treatment solely in the patient group. Our study revealed that thalamus volumes were reduced statistically significantly throughout the treatment period. However, we found that OFC volumes did not change statistically significantly throughout the treatment period. In summary, our study found that anti-obsessional drug treatment had an effect on thalamus volumes throughout the treatment period for both sides but not on OFC volumes. However, future studies with larger sample are required.

Hemispheric asymmetries in subcortical visual and auditory relay structures in congenital deafness

Neuroplasticity - the capacity of the brain to change as a response to internal and external pressures - has been studied from a number of different perspectives. Perhaps one of the most powerful models is the study of populations that have been congenitally deprived of a sense. It has been shown that the right Auditory Cortex (AC) of congenitally deaf humans is neuroplastically modified in order to represent visual properties of a stimulus. One unresolved question is how this visual information is routed to the AC of congenitally deaf individuals. Here, we performed volumetric analysis of subcortical auditory and visual brains regions - namely the thalamus (along with three thalamic nuclei: the pulvinar, the lateral geniculate nucleus and the medial geniculate nucleus), and the inferior and superior colliculi - in deaf and hearing participants in order to identify which structures may be responsible for relaying visual information toward the altered AC. Because there is a hemispheric asymmetry in the neuroplastic changes observed in the AC of the congenitally deaf, we reasoned that subcortical structures that also showed a similar asymmetry in their total volume could have been enlisted in the effort of relaying visual information to the neuroplastically altered right AC. We show that for deaf, but not for hearing individuals, the right thalamus, right lateral geniculate nucleus and right inferior colliculus are larger than their left counterparts. These results suggest that these subcortical structures may be responsible for rerouting visual information to the AC in congenital deafness.

Is There a Neuropathology of Schizophrenia? Recent Findings Converge on Altered Thalamic-Prefrontal Cortical Connectivity

Schizophrenia is a serious and chronic brain disorder whose underlying neuropathology has proven difficult to identify. This article reviews the current status of neuropathological studies in terms of how they inform the diagnosis, pathogenesis, pathophysiology, and mechanisms of treatment of schizophrenia. Although additional studies are required, substantial data converge on the hypothesis that the pathophysiology of schizophrenia is associated with alterations in thalamic-prefrontal cortical connectivity.

Using human brain imaging studies as a guide toward animal models of schizophrenia

Schizophrenia is a heterogeneous and poorly understood mental disorder that is presently defined solely by its behavioral symptoms. Advances in genetic, epidemiological and brain imaging techniques in the past half century, however, have significantly advanced our understanding of the underlying biology of the disorder. In spite of these advances clinical research remains limited in its power to establish the causal relationships that link etiology with pathophysiology and symptoms. In this context, animal models provide an important tool for causally testing hypotheses about biological processes postulated to be disrupted in the disorder. While animal models can exploit a variety of entry points toward the study of schizophrenia, here we describe an approach that seeks to closely approximate functional alterations observed with brain imaging techniques in patients. By modeling these intermediate pathophysiological alterations in animals, this approach offers an opportunity to (1) tightly link a single functional brain abnormality with its behavioral consequences, and (2) to determine whether a single pathophysiology can causally produce alterations in other brain areas that have been described in patients. In this review we first summarize a selection of well-replicated biological abnormalities described in the schizophrenia literature. We then provide examples of animal models that were studied in the context of patient imaging findings describing enhanced striatal dopamine D2 receptor function, alterations in thalamo-prefrontal circuit function, and metabolic hyperfunction of the hippocampus. Lastly, we discuss the implications of findings from these animal models for our present understanding of schizophrenia, and consider key unanswered questions for future research in animal models and human patients.

Altered Thalamo-Cortical White Matter Connectivity: Probabilistic Tractography Study in Clinical-High Risk for Psychosis and First-Episode Psychosis

Disrupted thalamo-cortical connectivity is regarded as a core psychopathology in patients diagnosed with schizophrenia. However, whether the thalamo-cortical white matter connectivity is disrupted before the onset of psychosis is still unknown. To determine this gap in knowledge, the strength of thalamo-cortical white matter anatomical connectivity in subjects at clinical-high risk for psychosis (CHR) was compared to that of first-episode psychosis (FEP) and healthy controls. A total of 37 CHR, 21 FEP, and 37 matched healthy controls underwent diffusion-weighted magnetic resonance imaging to examine the number of probabilistic tractography "counts" representing thalamo-cortical white matter connectivity. We also investigated the relationship with psychopathology. For FEP, the connectivity between the thalamus and parietal cortex was significantly increased (F= 5.65,P< .05) compared to that of healthy controls. However, the connectivity between thalamus and orbitofrontal cortex was significantly reduced compared to both healthy controls (F= 11.86,P< .005) and CHR (F= 6.63,P< .05). Interestingly, CHR exhibited a similar pattern as FEP, albeit with slightly reduced magnitude. Compared to healthy controls, there was a significant decrease (F= 4.16,P< .05) in CHR thalamo-orbitofrontal connectivity. Also, the strength of the thalamo-orbitofrontal connectivity was correlated with the Global Assessment of Functioning score in CHR (r= .35,P< .05). This observed pattern of white matter connectivity disruptions in FEP and in CHR suggests that this pattern of disconnectivity not only highlights the involvement of thalamus but also might be useful as an early biomarker for psychosis.

The thalamus as a putative biomarker in neurodegenerative disorders

OBJECTIVE

This review provides a brief account of the clinically relevant functional neuroanatomy of the thalamus, before considering the utility of various modalities utilized to image the thalamus and technical challenges therein, and going on to provide an overview of studies utilizing structural imaging techniques to map thalamic morphology in the spectrum of neurodegenerative disorders.

METHODS

A systematic search was conducted for peer-reviewed studies involving structural neuroimaging modalities investigating the morphology (shape and/or size) of the thalamus in the spectrum of neurodegenerative disorders.

RESULTS

While the precise role of the thalamus in the healthy brain remains unclear, there is a large body of knowledge accumulating which defines more precisely its functional connectivity within the connectome, and a burgeoning literature implicating its involvement in neurodegenerative disorders. It is proposed that correlation of clinical features with thalamic morphology (as a component of a quantifiable subcortical connectome) will provide a better understanding of neuropsychiatric dysfunction in various neurodegenerative disorders, potentially yielding clinically useful endophenotypes and disease biomarkers.

CONCLUSION

Thalamic biomarkers in the neurodegenerative disorders have great potential to provide clinically meaningful knowledge regarding not only disease onset and progression but may yield targets of and perhaps a way of gauging response to future disease-modifying modalities.

A schizophrenia-associated HLA locus affects thalamus volume and asymmetry

Genes of the Major Histocompatibility Complex (MHC) have recently been shown to have neuronal functions in the thalamus and hippocampus. Common genetic variants in the Human Leukocyte Antigens (HLA) region, human homologue of the MHC locus, are associated with small effects on susceptibility to schizophrenia, while volumetric changes of the thalamus and hippocampus have also been linked to schizophrenia. We therefore investigated whether common variants of the HLA would affect volumetric variation of the thalamus and hippocampus. We analysed thalamus and hippocampus volumes, as measured using structural magnetic resonance imaging, in 1.265 healthy participants. These participants had also been genotyped using genome-wide single nucleotide polymorphism (SNP) arrays. We imputed genotypes for single nucleotide polymorphisms at high density across the HLA locus, as well as HLA allotypes and HLA amino acids, by use of a reference population dataset that was specifically targeted to the HLA region. We detected a significant association of the SNP rs17194174 with thalamus volume (nominal P=0.0000017, corrected P=0.0039), as well as additional SNPs within the same region of linkage disequilibrium. This effect was largely lateralized to the left thalamus and is localized within a genomic region previously associated with schizophrenia. The associated SNPs are also clustered within a potential regulatory element, and a region of linkage disequilibrium that spans genes expressed in the thalamus, including HLA-A. Our data indicate that genetic variation within the HLA region influences the volume and asymmetry of the human thalamus. The molecular mechanisms underlying this association may relate to HLA influences on susceptibility to schizophrenia.

Validation of a protocol for manual segmentation of the thalamus on magnetic resonance imaging scans

We present a validated protocol for manual segmentation of the thalamus on T1-weighted magnetic resonance imaging (MRI) scans using brain image analysis software. The MRI scans of five normal control subjects were randomly selected from a larger cohort recruited from Lund University Hospital and Landskrona Hospital, Sweden. MRIs were performed using a 3.0T Philips MR scanner, with an eight-channel head coil, and high resolution images were acquired using a T1-weighted turbo field echo (T1 TFE) pulse sequence, with resulting voxel size 1×1×1 mm3. Manual segmentation of the left and right thalami and volume measurement was performed on 28-30 contiguous coronal slices, using ANALYZE 11.0 software. Reliability of image analysis was performed by measuring intra-class correlations between initial segmentation and random repeated segmentation of the left and right thalami (in total 10 thalami for segmentation); inter-rater reliability was measured using volumes obtained by two other experienced tracers. Intra-class correlations for two independent raters were 0.95 and 0.98; inter-class correlations between the expert rater and two independent raters were 0.92 and 0.98. We anticipate that mapping thalamic morphology in various neuropsychiatric disorders may yield clinically useful disease-specific biomarkers.

Early somatosensory processing in individuals at risk for developing psychoses

Human cortical somatosensory evoked potentials (SEPs) allow an accurate investigation of thalamocortical and early cortical processing. SEPs reveal a burst of superimposed early (N20) high-frequency oscillations around 600 Hz. Previous studies reported alterations of SEPs in patients with schizophrenia. This study addresses the question whether those alterations are also observable in populations at risk for developing schizophrenia or bipolar disorders. To our knowledge to date, this is the first study investigating SEPs in a population at risk for developing psychoses. Median nerve SEPs were investigated using multichannel EEG in individuals at risk for developing bipolar disorders (n = 25), individuals with high-risk status (n = 59) and ultra-high-risk status for schizophrenia (n = 73) and a gender and age-matched control group (n = 45). Strengths and latencies of low- and high-frequency components as estimated by dipole source analysis were compared between groups. Low- and high-frequency source activity was reduced in both groups at risk for schizophrenia, in comparison to the group at risk for bipolar disorders. HFO amplitudes were also significant reduced in subjects with high-risk status for schizophrenia compared to healthy controls. These differences were accentuated among cannabis non-users. Reduced N20 source strengths were related to higher positive symptom load. These results suggest that the risk for schizophrenia, in contrast to bipolar disorders, may involve an impairment of early cerebral somatosensory processing. Neurophysiologic alterations in schizophrenia precede the onset of initial psychotic episode and may serve as indicator of vulnerability for developing schizophrenia.

A review of structural neuroimaging in schizophrenia: from connectivity to connectomics

In patients with schizophrenia neuroimaging studies have revealed global differences with some brain regions showing focal abnormalities. Examining neurocircuitry, diffusion-weighted imaging studies have identified altered structural integrity of white matter in frontal and temporal brain regions and tracts such as the cingulum bundles, uncinate fasciculi, internal capsules and corpus callosum associated with the illness. Furthermore, structural co-variance analyses have revealed altered structural relationships among regional morphology in the thalamus, frontal, temporal and parietal cortices in schizophrenia patients. The distributed nature of these abnormalities in schizophrenia suggests that multiple brain circuits are impaired, a neural feature that may be better addressed with network level analyses. However, even with the advent of these newer analyses, a large amount of variability in findings remains, likely partially due to the considerable heterogeneity present in this disorder.

Disrupted thalamo-cortical connectivity in schizophrenia: a morphometric correlation analysis

Increasing studies have implicated the thalamus in schizophrenia, supporting the view that this structure has an important role in this disorder. Given that extensive reciprocal connections exist between the thalamus and the cerebral cortex, it is believed that disruptions of the thalamo-cortical connections may underlie the multiplicity of schizophrenic symptoms. Therefore, assessing the relationship between the thalamus and the neocortex may provide new insights into the pathophysiology of schizophrenia. We analyzed magnetic resonance images from a sample of 101 schizophrenic patients and 101 healthy controls. By assessing the correlation between the thalamic volume and cortical thickness at each vertex on the cortical surface, a thalamo-cortical network was obtained for each group. We compared the patterns of thalamo-cortical connectivity between the two groups. Compared with healthy controls, less distributed cortical regions were identified in the thalamo-cortical network in patients with schizophrenia. Vertex-wise comparison revealed decreased thalamo-cortical connectivity in bilateral inferior frontal gyrus, the left superior temporal gyrus and the right parieto-occipital region in schizophrenia. The observed disruptions in thalamo-cortical connectivity might be the substrate underlying the wide range of schizophrenic symptoms and provide further evidence to support the notion of schizophrenia as a disorder of brain dysconnectivity.

Imaging structural co-variance between human brain regions

Brain structure varies between people in a markedly organized fashion. Communities of brain regions co-vary in their morphological properties. For example, cortical thickness in one region influences the thickness of structurally and functionally connected regions. Such networks of structural co-variance partially recapitulate the functional networks of healthy individuals and the foci of grey matter loss in neurodegenerative disease. This architecture is genetically heritable, is associated with behavioural and cognitive abilities and is changed systematically across the lifespan. The biological meaning of this structural co-variance remains controversial, but it appears to reflect developmental coordination or synchronized maturation between areas of the brain. This Review discusses the state of current research into brain structural co-variance, its underlying mechanisms and its potential value in the understanding of various neurological and psychiatric conditions.

Post-stroke dementia: the contribution of thalamus and basal ganglia changes

BACKGROUND

The neurobiological basis of increased risk of dementia in stroke patients is unclear, though there are several related pathological changes, including white matter hyperintensities (WMH), and medial temporal atrophy. Subcortical gray matter structures have also been implicated in dementia resulting from vascular pathology, particularly vascular dementia. This study aimed to investigate the contribution of changes in subcortical gray matter structures to post-stroke dementia (PSD).

METHODS

T1- and T2-weighted images and T2-weighted fluid-attenuated inversion recovery (FLAIR) images were obtained on a 3-Tesla magnetic resonance (MR) system, in four groups aged over 75 years: post-stroke with dementia (PSD; 8), post-stroke no dementia (PSnoD; 33), Alzheimer's disease (AD; 26) and controls (30). Automated software was used to measure the volume of thalamus, putamen, caudate nucleus, and hippocampus as well as total WMH volume. The number of subcortical lacunes was also counted.

RESULTS

The number of caudate lacunes was higher in the PSnoD group, compared with AD (p = 0.029) and controls (p = 0.019). The putamen volume was smaller in the stroke and AD groups, when compared with controls. In the whole stroke group, putamen lacunes were correlated with impairment in memory (Rey test; ρ = -0.365; p = 0.031), while WMH and hippocampal volume both correlated with global dysfunction.

CONCLUSION

Our findings implicate a variety of neurobiological substrates of dementia, such as small vessel disease and Alzheimer pathology, which develop after stroke in an old older population, with a contribution from subcortical brain structures.

BrainKnowledge: a human brain function mapping knowledge-base system

Associating fMRI image datasets with the available literature is crucial for the analysis and interpretation of fMRI data. Here, we present a human brain function mapping knowledge-base system (BrainKnowledge) that associates fMRI data analysis and literature search functions. BrainKnowledge not only contains indexed literature, but also provides the ability to compare experimental data with those derived from the literature. BrainKnowledge provides three major functions: (1) to search for brain activation models by selecting a particular brain function; (2) to query functions by brain structure; (3) to compare the fMRI data with data extracted from the literature. All these functions are based on our literature extraction and mining module developed earlier (Hsiao, Chen, Chen. Journal of Biomedical Informatics 42, 912-922, 2009), which automatically downloads and extracts information from a vast amount of fMRI literature and generates co-occurrence models and brain association patterns to illustrate the relevance of brain structures and functions. BrainKnowledge currently provides three co-occurrence models: (1) a structure-to-function co-occurrence model; (2) a function-to-structure co-occurrence model; and (3) a brain structure co-occurrence model. Each model has been generated from over 15,000 extracted Medline abstracts. In this study, we illustrate the capabilities of BrainKnowledge and provide an application example with the studies of affect. BrainKnowledge, which combines fMRI experimental results with Medline abstracts, may be of great assistance to scientists not only by freeing up resources and valuable time, but also by providing a powerful tool that collects and organizes over ten thousand abstracts into readily usable and relevant sources of information for researchers.

Do defense styles of ego relate to volumes of orbito-frontal cortex in patients with obsessive-compulsive disorder?

OBJECTIVE

Although the importance of orbito-frontal cortex (OFC) is established in the pathogenesis of obsessive compulsive disorder (OCD), no study have evaluated its relation to the traditional psychodynamic perspective. In the present study, we aimed to evaluate the relationship between the defense styles consisting of mature, immature and neurotic defenses and OFC volumes of patients with OCD.

METHODS

Subjects were selected among those of our previous study, and so eighteen patients with OCD and same number of healthy controls were took into the study. The patients and controls had underwent magnetic resonance imaging (MRI). In addition, the Defense Style Questionnaire-40 was administered to obtain defense styles of patients and controls.

RESULTS

No significant relationship was found between the right OFC volumes of both the patient and control groups and their scores of mature, neurotic, or immature defense mechanisms. As for the left OFC volumes, the only significant relationship for the scores of immature defense mechanism was found in the patient group.

CONCLUSION

The results of the present study indicated that there was no significant relationship between OFC volumes of the patient group and their scores of mature, neurotic, or immature defense mechanisms, except a significant relation with the scores of immature defense mechanisms.

Serotonin transporter gene polymorphism implicates reduced orbito-frontal cortex in obsessive-compulsive disorder

Although a number of magnetic resonance imaging (MRI) and genetic studies have been performed on obsessive-compulsive disorder (OCD), only limited studies in which genetic and neuroanatomical variables are evaluated concurrently have been performed. Therefore, the aim of our present study is (to understand) better understanding how genetic variation in the promoter region of the 5-HTT gene (5-HTTLPR) is associated with key brain structures in OCD, orbito-frontal cortex (OFC), thalamus and anterior cingulate. 5-HTT genotypes (SS, SL, LL) were determined for 40 patients with OCD and the same number of healthy controls. MRI-derived volumes of the OFC, thalamus, and anterior cingulate were determined by reliable tracing techniques. Volumetric measurements were made with T1-weighted coronal MRI images, with 1.5-mm-thick slices, at 1.5T, and were done blindly. In comparison with controls, OCD patients demonstrated volumes reduction in OFC, increased volumes of thalamus and total white matter volumes, but no difference in total brain volume, total gray matter volumes and anterior cingulate volumes. No significant difference was observed in allelic frequencies between the patients and controls. The stronger effects of 5-HTT polymorphism on brain morphology in OCD than those in controls were determined in the both OFC and thalamus. On the other hand, for the OCD patients, ANCOVA revealed a significant main effect of genotype for both the OFC and thalamus and a significant genotype-by-side interaction for the OFC, demonstrating that the short variants had a smaller right OFC than the long variants. In conclusion, we found a significant genotype-diagnosis interaction effects on key brain structures, with a stronger effects of 5-HTT polymorphism in OFC and thalamus of OCD patients, whereas no morphological changes related to the polymorphism were found in normal individuals.

Correlations of cerebello-thalamo-prefrontal structure and neurological soft signs in patients with first-episode psychosis

OBJECTIVE

This study aimed at determining brain structural imaging correlates of neurological soft signs (NSS) in patients suffering from a first-episode psychosis.

METHOD

Fifty-two patients with a DSMIV diagnosis of first-episode psychosis (schizophrenia or schizophrenia spectrum disorder) were consecutively included. Subjects were assessed using a standardized neurological examination for motor coordination, motor integration and sensory integration. Anatomical magnetic resonance images (MRI) were analysed in the whole brain using optimized voxel-based morphometry.

RESULTS

Neurological soft signs (NSS) total score (P-corrected = 0.013) and motor integration subscore (P-corrected = 0.035) were found to negatively correlate with grey matter structure of the dorsolateral prefrontal cortices. Motor coordination subscore was positively correlated with grey matter structure of the thalami (P-corrected = 0.002) and negatively with white matter structure of the cerebellum (P-corrected = 0.034). The addition of age and gender as covariate yielded similar results. We did not find any correlation between neither sensory integration subscore and grey matter structure nor NSS total score, motor integration subscore and voxel-based morphometry (VBM) white matter structure.

CONCLUSION

Structural alteration in the cerebello-thalamo-prefrontal network is associated with neurological soft signs in schizophrenia, a candidate network for 'cognitive dysmetria'.

Regional volume analysis of the Parkinson disease brain in early disease stage: gray matter, white matter, striatum, and thalamus

BACKGROUND AND PURPOSE

Loss of dopaminergic neurons in the nigrostriatal pathway is well-documented in PD, whereas neuronal changes beyond the nigrostriatal pathway are uncertain. The purpose of our study was to estimate volume changes in the striatum and thalamus, which are areas of the basal ganglia, as well as in GM and WM located beyond the nigrostriatal pathway, in early-stage PD.

MATERIALS AND METHODS

We enrolled 30 participants (15 healthy controls and 15 patients with PDND with H & Y stage I or II). Cognitive function was assessed by using the MMSE. ICV and the volumes of the caudate nucleus, putamen, thalamus, GM, and WM were calculated via 3D volume analysis by using MR imaging.

RESULTS

A comparison of the PD group with the control group revealed an absence of significant differences between them regarding age and MMSE scores. Comparison of the volumes of regional brain structures of patients with PD with those of controls revealed the presence of significant differences in the caudate nucleus, thalamus, and WM (P<.05) between the groups. However, there were no significant differences in the volumes of the putamen and GM or in ICV between patients with PD and controls. The results of ANCOVA by using the covariates of age and ICV showed a significant difference in the caudate nucleus, thalamus, and WM between patients with PD and controls (P<.05).

CONCLUSIONS

We suggest that loss of WM volume may occur in early disease stages and that variation of the volumes of the caudate nucleus and thalamus may be an early phenomenon of disease progression.

Correlations between ventricular enlargement and gray and white matter volumes of cortex, thalamus, striatum, and internal capsule in schizophrenia

Ventricular enlargement is one of the most consistent abnormal structural brain findings in schizophrenia and has been used to infer brain shrinkage. However, whether ventricular enlargement is related to local overlying cortex and/or adjacent subcortical structures or whether it is related to brain volume change globally has not been assessed. We systematically assessed interrelations of ventricular volumes with gray and white matter volumes of 40 Brodmann areas (BAs), the thalamus and its medial dorsal nucleus and pulvinar, the internal capsule, caudate and putamen. We acquired structural MRI ( patients with schizophrenia (n = 64) and healthy controls (n = 56)) and diffusion tensor fractional anisotropy (FA) (untreated schizophrenia n = 19, controls n = 32). Volumes were assessed by manual tracing of central structures and a semi-automated parcellation of BAs. Patients with schizophrenia had increased ventricular size associated with decreased cortical gray matter volumes widely across the brain; a similar but less pronounced pattern was seen in normal controls; local correlations (e.g. temporal horn with temporal lobe volume) were not appreciably higher than non-local correlations (e.g. temporal horn with prefrontal volume). White matter regions adjacent to the ventricles similarly did not reveal strong regional relationships. FA and center of mass of the anterior limb of the internal capsule also appeared differentially influenced by ventricular volume but findings were similarly not regional. Taken together, these findings indicate that ventricular enlargement is globally interrelated with gray matter volume diminution but not directly correlated with volume loss in the immediately adjacent caudate, putamen, or internal capsule.

Updated meta-analyses reveal thalamus volume reduction in patients with first-episode and chronic schizophrenia

OBJECTIVES

Although several structural MRI studies report significant thalamus volume reduction in patients with schizophrenia, many other studies do not. Therefore, the present meta-analyses aimed to clarify whether a reduction in thalamic volume characterizes patients diagnosed with schizophrenia by considering first-episode and chronic phases of the illness and right and left thalamus separately.

METHODS

Using Pubmed databases, we made a detailed literature search for structural MRI studies on patients with schizophrenia that reported physical volumetric measures of the right and left thalamus. Thirteen structural MRI studies were considered eligible for meta-analysis of the entire sample of patients and of the healthy control subjects. Individual meta-analyses were also performed on 6 studies of first-episode patients only and on 7 studies of chronic patients only. These were followed by additional meta-analyses to investigate the role of the factors "illness phase" and "side" on thalamic volume reduction.

RESULTS

Overall, the patient group showed a significant bilateral thalamus volume reduction compared to healthy control subjects. This was found in both first-episode and chronic patients. Furthermore, left thalamus was smaller than right in both patients and healthy control subjects.

CONCLUSIONS

When only studies that used physical volumetric measures were considered, the present meta-analyses confirmed that thalamic volume reduction characterizes patients with schizophrenia, both at the first-episode and chronic phases of the illness.

Anterior thalamic radiation integrity in schizophrenia: a diffusion-tensor imaging study

The anterior limb of the internal capsule (ALIC) is a white matter structure, the medial portion of which includes the anterior thalamic radiation (ATR) carrying nerve fibers between thalamus and prefrontal cortex. ATR abnormalities have a possible link with cognitive abnormalities and negative symptoms in schizophrenia. We aimed to study the fiber integrity of the ATR more selectively by isolating the medial portion of the ALIC using region-of-interest based methodology. Diffusion-tensor imaging was used to measure the anisotropy of total ALIC (tALIC) and medial ALIC (mALIC) in 39 schizophrenia and 33 control participants, matched for age/gender/handedness. Relationships between anisotropy, psychopathology, and cognitive performance were analyzed. Compared with controls, schizophrenia participants had 4.55% lower anisotropy in right tALIC, and 5.38% lower anisotropy in right mALIC. There were no significant group anisotropy differences on the left. Significant correlations were observed between right ALIC integrity and relevant domains of cognitive function (e.g., executive function, working memory). Our study suggests an asymmetric microstructural change in ALIC in schizophrenia involving the right side, which is only minimally stronger in mALIC, and which correlates with cognitive impairment. Microstructural changes in the ALIC may be linked to cognitive dysfunction in schizophrenia.

Clinical correlates of thalamus volume deficits in anti-psychotic-naïve schizophrenia patients: A 3-Tesla MRI study

BACKGROUND

Thalamus, the sensory and motor gateway to the cortex, plays an important role in cognitive and perceptual disturbances in schizophrenia. Studies examining the volume of the thalamus in schizophrenia have reported conflicting findings due to the presence of potential confounding factors such as low-resolution imaging and anti-psychotics. The thalamus volume in anti-psychotic-naïve patients determined using high-resolution 3-Tesla magnetic resonance imaging (MRI) has not yet been examined.

MATERIALS AND METHODS

Using 3-Tesla MRI, this study for the first time examined anti-psychotic-naïve schizophrenia patients (n=18; M:F:11:7) in comparison with healthy controls (n=19;M:F:9:10) group-matched for age, sex, handedness, education, and socioeconomic status. The volume of the thalamus was measured using a three-dimensional, interactive, semi-automated analysis with good inter-rater and intra-rater reliability. Psychopathology was assessed using the Scale for Assessment of Negative Symptoms (SANS) and the Scale for Assessment of Positive Symptoms (SAPS).

RESULTS

Right, left, and total thalamus volumes of patients were significantly smaller than those of controls after controlling for the potential confounding effect of intracranial volume. Thalamus volumes had significant positive correlation with positive symptoms score (SAPS) and significant negative correlation with negative symptoms score (SANS).

CONCLUSIONS

Thalamus volume deficits in anti-psychotic-naïve schizophrenia patients support a neurodevelopmental pathogenesis. The contrasting correlation of thalamus volume deficits with psychopathology scores suggests that contrasting pruning aberrations underlie symptom genesis in schizophrenia.

Brain morphology of patients with body dysmorphic disorder

BACKGROUND

There has been dearth of investigations concerning morphometric magnetic resonance imaging (MRI) study of regional brain volumes in body dysmorphic disorder (BDD). So we performed a volumetric MRI study in patients with BDD focusing on the in vivo neuroanatomy of thalamus, caudate nucleus, anterior cingulate cortex, and orbito-frontal cortex (OFC) concurrently.

METHODS

The whole brain, total gray and white matter volume, thalamus, caudate nucleus, anterior cingulate cortex, and OFC volumes were blindly measured in 12 unmedicated male BDD patients not having any comorbidity and 12 male control subjects matched for age, and gender.

RESULTS

The mean OFC and anterior cingulate volumes were significantly smaller than those of healthy controls. The mean white matter volume was larger than that of controls. There was a trend toward increased thalamic volume in patients compared with that of control subjects. Length of illness was inversely correlated with OFC volumes in the patient group both on the left and right sides.

CONCLUSIONS

These findings may be interpreted as further evidence for the inclusion of BDD among a group of obsessive-compulsive spectrum disorders. Future research is necessary to confirm these preliminary findings, to extend them, and to clarify their significance with respect to the etiology and pathophysiology of BDD.

Thalamic pathology in schizophrenia

The thalamus plays a critical role in the coordination of information as it passes from region to region within the brain. A disruption of that information flow may give rise to some of the cardinal symptoms of schizophrenia. In support of this hypothesis, schizophrenia-like syndromes emerge when illnesses, such as stroke, selectively damage the thalamus while sparing the rest of the brain. Evidence from many sources has implicated thalamic dysfunction in schizophrenia. In postmortem studies, several subregions of the thalamus, including the mediodorsal nucleus and the pulvinar, have been shown to have fewer neurons in schizophrenia. Neurochemical disturbances are also seen, with changes in both the glutamate and dopamine systems; thalamic glutamate receptor expression is altered in schizophrenia, and dopamine appears to be elevated in thalamic subregions, while evidence exists of an imbalance between dopamine and other neurotransmitters. In vivo studies using magnetic resonance imaging have demonstrated smaller thalamic volumes in schizophrenia, as well as shape deformations suggesting changes in those thalamic regions that are most densely connected to the portions of the brain responsible for executive function and sensory integration. These changes seem to be correlated with clinical symptoms. The thalamus is a starting point for several parallel, overlapping networks that extend from thalamic nuclei to the cortex. Evidence is emerging that changes in the thalamic nodes of these networks are echoed by changes at other points along the chain; this suggests that schizophrenia might be a disease of disrupted thalamocortical neural networks. This model distributes the pathology throughout the network, but also concentrates attention on the thalamus as a critical structure, especially because of its role in coordinating the flow of information within and between neural networks.

Modeling "psychosis" in vitro by inducing disordered neuronal network activity in cortical brain slices

INTRODUCTION

Dysregulation of neuronal networks has been suggested to underlie the cognitive and perceptual abnormalities observed schizophrenia.

DISCUSSIONS

An in vitro model of psychosis is proposed based on the two different approaches to cause aberrant network activity in layer V pyramidal cells of prefrontal brain slices: (1) psychedelic hallucinogens such as lysergic acid diethylamide and (2) minimal GABA(A) receptor antagonism, modeling the GABA interneuron deficit in schizophrenia. A test of this model would be to determine if drugs that normalize aberrant networks in brain slices have efficacy in the treatment of schizophrenia. Selective agonists of glutamate mGlu2/3 metabotropic receptors, which are highly effective in suppressing aberrant network activity in slices, are the most advanced toward reaching that clinical endpoint. In accord with the model, a recent phase II clinical trial shows that an mGlu2/3 receptor agonist is equivalent in efficacy to a standard antipsychotic drug for both negative and positive symptoms in schizophrenic patients, but without the usual side effects. D1/5 dopamine receptor agonists are also effective in normalizing aberrant network activity induced by both hallucinogens and minimal GABA(A) antagonism; clinical efficacy remains to be determined. A general model of network regulation is presented, involving astrocytes, GABA interneurons, and glutamatergic pyramidal cells, revealing a wide range of potential sites hitherto not considered as therapeutic targets.

Selective reduction of neuron number and volume of the mediodorsal nucleus of the thalamus in macaques following irradiation at early gestational ages

Neurons in the macaque brain arise from progenitors located near the cerebral ventricles in a temporally segregated manner such that lethal doses of ionizing irradiation, if administered over a discrete time interval, can deplete individual nuclei selectively. A previous study showed that neuron number in the dorsal lateral geniculate nucleus is reduced following early gestational exposure to x-irradiation (Algan and Rakic [1997] J. Comp. Neurol. 12:335-352). Here we examine whether similarly timed irradiation decreases neuron number in three associational thalamic nuclei: mediodorsal (MD), anterior, and pulvinar. Ten macaques were exposed to multiple doses of x-rays (total exposure (175-350 cGy) in early gestation (E33-E42) or midgestation (E70-E90); eight nonirradiated macaques were controls. Only the early-irradiated monkeys, not the midgestationally irradiated animals, exhibited deficits in whole-thalamic neuron (-15%) and glia numbers (-21%) compared with controls. Reduction of neuron number (-26%) and volume (-29%) was particularly pronounced in MD. In contrast, cell number and volume were not significantly decreased in the anterior or pulvinar nuclei following early gestational irradiation. Thus, reduced thalamic neuron number was associated specifically with irradiation in early gestation. Persistence of the thalamic neuronal deficit in adult animals indicates that prenatally deleted neurons had not been replenished during maturation or in adulthood. The selective reduction of MD neuron number also supports the protomap hypothesis that neurons of each thalamic nucleus originate sequentially from separate lines of neuronal stem cells (Rakic [1977a] J. Comp. Neurol. 176:23-52). The early gestationally irradiated macaque is discussed as a potentially useful model for studying the neurodevelopmental pathogenesis of schizophrenia.

Volumetric and shape analysis of the thalamus in first-episode schizophrenia

Thalamic abnormalities have been implicated in the pathogenesis of schizophrenia, although the majority of studies used chronic samples treated extensively with antipsychotics. Moreover, the clinical and neuropsychological correlates of these abnormalities remain largely unknown. Using high-resolution MR imaging and novel methods for shape analysis, we investigated thalamic subregions in 35 (25 M/10 F) first-episode schizophrenia patients compared with 33 (23 M/10 F) healthy volunteers. The right and left thalami were traced bilaterally on coronal brain slices and volumes were compared between groups. In addition, regional abnormalities were identified by comparing distances, measured from homologous thalamic surface points to the central core of each individual's surface model, between groups in 3D space. Patients had significantly less total thalamic volume compared with healthy volunteers. Statistical mapping demonstrated most pronounced shape abnormalities in the pulvinar; however, estimated false discovery rates in these regions were sizable. Smaller thalamus volume was significantly correlated with worse overall neuropsychological functioning and specific deficits were observed in the language, motor, and executive domains. There were no significant associations between thalamus volume and positive or negative symptoms. Our findings suggest that thalamic abnormalities are evident at the onset of a first episode of schizophrenia prior to extensive pharmacologic intervention and that these abnormalities have neuropsychological correlates.

Meta-analysis of brain volume changes in obsessive-compulsive disorder

BACKGROUND

Many neuroimaging studies exploring the volumes of brain structures in obsessive-compulsive disorder (OCD) have been published in the past 2 decades. In this study, we attempted to provide a complete overview of structural alterations in OCD by meta-analyzing magnetic resonance imaging (MRI) data.

METHODS

We conducted a systematic search of MRI studies that reported volumetric measurements in both OCD patients and healthy subjects. Data were entered into the meta-analysis through calculation of the standardized mean differences (SMDs) between the volumes of cerebral regions in OCD patients and the corresponding volumes in control subjects. We then performed a meta-regression to explore the influence of clinical covariates on effect sizes.

RESULTS

Although no volumetric differences were found for the whole brain, intracranial region, gray matter, or prefrontal cortex, OCD patients did show a reduced volume of the left anterior cingulate cortex (ACC) and the left and right orbitofrontal cortex (OFC). No significant volumetric differences within the basal ganglia were observed, although the left and right thalamic volumes were significantly increased in OCD patients. The severity of obsessive or compulsive symptoms correlated significantly with the effect sizes for the left and right thalamus.

CONCLUSIONS

Our findings indicate volumetric differences between OCD patients and control subjects in the cortical and thalamic regions, suggesting that structural alteration of the thalamocortical pathways may contribute to the functional disruptions of frontosubcortical circuits observed in OCD.

Joint segmentation of thalamic nuclei from a population of diffusion tensor MR images

Several recent studies explored the use of unsupervised segmentation methods for segmenting thalamic nuclei from diffusion tensor images. These methods provide a plausible segmentation on individual subjects; however, they do not address the problem of consistently identifying the same functional areas in a population. The lack of correspondence between the segmented nuclei make it more difficult to use the results from the unsupervised segmentation tools for morphometry. In this paper we present a novel segmentation algorithm to automatically segment the gray matter nuclei while ensuring consistency between subjects in a population. This new algorithm, referred to as Consistency Clustering, finds correspondence between the nuclei as the segmentation is achieved through a single model for the whole population, similar to the brain atlases experts use to identify thalamic nuclei.

Diffusion tensor imaging of hemispheric asymmetries in the developing brain

Diffusion tensor imaging (DTI) was performed in 39 right-handed children to examine structural hemispheric differences and the impact of age, socioeconomic status, and sex on these differences. Apparent diffusion coefficient (ADC) values were smaller in the left than in the right temporal, prefrontal, anterior internal capsular and the thalamic regions, and fractional anisotropy (FA) values were larger in the left than in the right internal capsule, thalamus, and cingulate. Significant region-by-sex interactions disclosed that the relation of DTI asymmetries to performance depended on sex including the relation of temporal lobes to reading comprehension and the relation of frontal lobes to solving applied mathematical problems.

Voxel-based morphometry in schizophrenia: implications for neurodevelopmental connectivity models, cognition and affect

Voxel-based morphometry (VBM) studies have provided valuable data on the nature and distribution of gray and white matter abnormalities in schizophrenia relative to the whole brain. Most VBM studies have focused on chronic patients, but there are accumulating studies of first-episode schizophrenia and other high-risk groups such as first-degree relatives. This review outlines the evidence from VBM studies of both chronic and first-episode/high-risk groups. The most consistent reduction revealed in chronic patients is in the superior temporal cortex, and in first-episode/high-risk individuals, in frontal brain regions. These findings are reviewed in relation to complementary evidence for neurodevelopmental deviation, and functional associations with both neuroimaging and behavioral measures of general and social cognition.

Thalamus surface shape deformity in obsessive-compulsive disorder and schizophrenia

The authors performed a three-dimensional shape deformation analysis to clarify the various patterns of specific thalamic nuclei abnormality using three age-matched and sex-matched groups of 22 patients with obsessive-compulsive disorder (OCD), 22 patients with schizophrenia and 22 control participants. Compared with the healthy volunteers, the anterior, lateral outward surface deformities of the thalamus were significant in OCD patients, whereas the posterior, medial outward deformities of the thalamus were prominent in schizophrenia patients. In terms of thalamic asymmetry, both OCD and schizophrenia patients exhibited the loss of a leftward pattern of asymmetry on the posterior, medial surface of the thalamus. Different patterns of shape abnormality of specific thalamic nuclei may be related to the different phenomenology of OCD and schizophrenia.

Limbic structures and networks in children and adolescents with schizophrenia

Studies of adults with schizophrenia provide converging evidence for abnormalities in the limbic system. Limbic structures that show consistent patient/control differences in both postmortem and neuroimaging studies include the anterior cingulate and hippocampus, although differences in the amygdala, parahippocampal gyrus, and fornix have also been observed. Studies of white matter in children and adolescents with schizophrenia tend to show findings that are more focal than those seen in adults. Interestingly, these focal abnormalities in early-onset schizophrenia tend to be more localized to limbic regions. While it is unclear if these early limbic abnormalities are primary in the etiology of schizophrenia, there is evidence that supports a developmental progression with early limbic abnormalities evolving over time to match the neuroimaging profiles seen in adults with schizophrenia. Alternatively, the aberrations in limbic structures may be secondary to a more widespread or global pathological processes occurring with the brain that disrupt neural transmission. The goal of this article is to provide a review of the limbic system and limbic network abnormalities reported in children and adolescents with schizophrenia. These findings are compared with the adult literature and placed within a developmental context. These observations from neuroimaging studies enrich our current understanding of the neurodevelopmental model of schizophrenia and raise further questions about primary vs secondary processes. Additional research within a developmental framework is necessary to determine the putative etiologic roles for limbic and other brain abnormalities in early-onset schizophrenia.