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Mukherjee D, Kanold PO. Changing subplate circuits: Early activity dependent circuit plasticity. Front Cell Neurosci 2023; 16:1067365. [PMID: 36713777 PMCID: PMC9874351 DOI: 10.3389/fncel.2022.1067365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/16/2022] [Indexed: 01/12/2023] Open
Abstract
Early neural activity in the developing sensory system comprises spontaneous bursts of patterned activity, which is fundamental for sculpting and refinement of immature cortical connections. The crude early connections that are initially refined by spontaneous activity, are further elaborated by sensory-driven activity from the periphery such that orderly and mature connections are established for the proper functioning of the cortices. Subplate neurons (SPNs) are one of the first-born mature neurons that are transiently present during early development, the period of heightened activity-dependent plasticity. SPNs are well integrated within the developing sensory cortices. Their structural and functional properties such as relative mature intrinsic membrane properties, heightened connectivity via chemical and electrical synapses, robust activation by neuromodulatory inputs-place them in an ideal position to serve as crucial elements in monitoring and regulating spontaneous endogenous network activity. Moreover, SPNs are the earliest substrates to receive early sensory-driven activity from the periphery and are involved in its modulation, amplification, and transmission before the maturation of the direct adult-like thalamocortical connectivity. Consequently, SPNs are vulnerable to sensory manipulations in the periphery. A broad range of early sensory deprivations alters SPN circuit organization and functions that might be associated with long term neurodevelopmental and psychiatric disorders. Here we provide a comprehensive overview of SPN function in activity-dependent development during early life and integrate recent findings on the impact of early sensory deprivation on SPNs that could eventually lead to neurodevelopmental disorders.
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Affiliation(s)
- Didhiti Mukherjee
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States
| | - Patrick O. Kanold
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States,*Correspondence: Patrick O. Kanold ✉
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King VL, Lahti AC, Maximo JO, ver Hoef LW, John S, Kraguljac NV. Contrasting Frontoparietal Network Connectivity in Antipsychotic Medication-Naive First-Episode Psychosis Patients Who Do and Do Not Display Features of the Deficit Syndrome. Schizophr Bull 2022; 48:1344-1353. [PMID: 35869578 PMCID: PMC9673254 DOI: 10.1093/schbul/sbac081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The deficit syndrome is a clinical subtype of schizophrenia that is characterized by enduring negative symptoms. Several lines of evidence point to frontoparietal involvement, but the frontoparietal control network (FPCN) and its subsystems (FPCNA and FPCNB) proposed by Yeo et al. have not been systematically characterized at rest in patients with the deficit syndrome. METHODS We used resting-state fMRI to investigate the FPCN and its subnetworks in 72 healthy controls and 65 antipsychotic medication-naive, first-episode psychosis patients (22 displayed deficit syndrome features, 43 did not). To assess whole-brain FPCN connectivity, we used the right posterior parietal cortex as the seed region. We then performed region of interest analyses in FPCN subsystems. RESULTS We found that patterns of FPCN dysconnectivity to the whole brain differed in patients who displayed deficit syndrome features compared with those who did not. Examining the FPCN on a more granular level revealed reduced within-FPCN(A) connectivity only in patients displaying deficit features. FPCNB connectivity did not differ between patient groups. DISCUSSION Here, we describe a neurobiological signature of aberrant FPCN connectivity in antipsychotic-naive, first-episode patients who display clinical features of the deficit syndrome. Importantly, frontoparietal subnetwork connectivity differentiated subgroups, where the FPCNA is selectively involved in patients with deficit features. Our findings add to the growing body of literature supporting a neurobiological distinction between two clinical subtypes of schizophrenia, which has the potential to be leveraged for patient stratification in clinical trials and the development of novel treatments.
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Affiliation(s)
- Victoria L King
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Adrienne C Lahti
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jose O Maximo
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lawrence W ver Hoef
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sooraj John
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nina V Kraguljac
- To whom correspondence should be addressed; Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, SC 501, 1720 7th Ave S, Birmingham, AL 35294-0017, USA; tel: 205-996-7171, e-mail:
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3
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Lei D, Suo X, Qin K, Pinaya WHL, Ai Y, Li W, Kuang W, Lui S, Kemp GJ, Sweeney JA, Gong Q. Magnetization transfer imaging alterations and its diagnostic value in antipsychotic-naïve first-episode schizophrenia. Transl Psychiatry 2022; 12:189. [PMID: 35523792 PMCID: PMC9076920 DOI: 10.1038/s41398-022-01939-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/15/2022] [Accepted: 04/20/2022] [Indexed: 02/08/2023] Open
Abstract
Magnetization transfer imaging (MTI) may provide more sensitivity and mechanistic understanding of neuropathological changes associated with schizophrenia than volumetric MRI. This study aims to identify brain magnetization transfer ratio (MTR) changes in antipsychotic-naïve first-episode schizophrenia (FES), and to correlate MTR findings with clinical symptom severity. A total of 143 individuals with antipsychotic-naïve FES and 147 healthy controls (HCs) were included and underwent 3.0 T brain MTI between August 2005 and July 2014. Voxelwise analysis was performed to test for MTR differences with family-wise error corrections. Relationships of these differences to symptom severity were assessed using partial correlations. Exploratory analyses using a support vector machine (SVM) classifier were conducted to discriminate FES from HCs using MTR maps. Model performance was examined using a 10-fold stratified cross-validation. Compared with HCs, individuals with FES exhibited higher MTR values in left thalamus, precuneus, cuneus, and paracentral lobule, that were positively correlated with schizophrenia symptom severity [precuneus (r = 0.34, P = 0.0004), cuneus (r = 0.33, P = 0.0006) and paracentral lobule (r = 0.37, P = 0.001)]. Whole-brain MTR maps identified individuals with FES with overall accuracy 75.5% (219 of 290 individuals) based on SVM approach. In antipsychotic-naïve FES, clinically relevant biophysical abnormalities detected by MTI mainly in the left parieto-occipital regions are informative about local brain pathology, and have potential as diagnostic markers.
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Affiliation(s)
- Du Lei
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, 45227, USA
| | - Xueling Suo
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
| | - Kun Qin
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
| | - Walter H L Pinaya
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, WC2R 2LS, UK
| | - Yuan Ai
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
| | - Wenbin Li
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
| | - Weihong Kuang
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
- Research Unit of Psychoradiology, Chinese Academy of Medical Sciences, Chengdu, Sichuan, 610041, China
| | - Su Lui
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
- Functional and Molecular Imaging Key Laboratory of Sichuan Province, West China Hospital of Sichuan University, Chengdu, Sichuan, 610041, China
| | - Graham J Kemp
- Liverpool Magnetic Resonance Imaging Centre (LiMRIC) and Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L69 3GE, UK
| | - John A Sweeney
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, 45227, USA
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China.
- Department of Radiology, West China Xiamen Hospital of Sichuan University, Xiamen, Fujian, 361022, China.
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Sóki N, Richter Z, Karádi K, Lőrincz K, Horváth R, Gyimesi C, Szekeres-Paraczky C, Horváth Z, Janszky J, Dóczi T, Seress L, Ábrahám H. Investigation of synapses in the cortical white matter in human temporal lobe epilepsy. Brain Res 2022; 1779:147787. [PMID: 35041843 DOI: 10.1016/j.brainres.2022.147787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/27/2021] [Accepted: 01/10/2022] [Indexed: 11/02/2022]
Abstract
Temporal lobe epilepsy (TLE) is one of the most common focal pharmacotherapy-resistant epilepsy in adults. Previous studies have shown significantly higher numbers of neurons in the neocortical white matter in TLE patients than in controls. The aim of this work was to investigate whether white matter neurons are part of the neuronal circuitry. Therefore, we studied the distribution and density of synapses in surgically resected neocortical tissue of pharmacotherapy-resistant TLE patients. Neocortical white matter of temporal lobe from non-epileptic patients were used as controls. Synapses and neurons were visualized with immunohistochemistry using antibodies against synaptophysin and NeuN, respectively. The presence of synaptophysin in presynaptic terminals was verified by electron microscopy. Quantification of immunostaining was performed and the data of the patients' cognitive tests as well as clinical records were compared to the density of neurons and synapses. Synaptophysin density in the white matter of TLE patients was significantly higher than in controls. In TLE, a significant correlation was found between synaptophysin immunodensity and density of white matter neurons. Neuronal as well as synaptophysin density significantly correlated with scores of verbal memory of TLE patients. Neurosurgical outcome of TLE patients did not significantly correlate with histological data, although, higher neuronal and synaptophysin densities were observed in patients with favorable post-surgical outcome. Our results suggest that white matter neurons in TLE patients receive substantial synaptic input and indicate that white matter neurons may be integrated in epileptic neuronal networks responsible for the development or maintenance of seizures.
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Affiliation(s)
- Noémi Sóki
- Department of Medical Biology and Central Electron Microscopic Laboratory, University of Pécs Medical School Szigeti u. 12. Pécs, 7643, Hungary; Neuromorphology and Cellular Neurobiology Research Group, Center for Neuroscience, University of Pécs Ifjúság u. 20. Pécs, 7624, Hungary
| | - Zsófia Richter
- Department of Medical Biology and Central Electron Microscopic Laboratory, University of Pécs Medical School Szigeti u. 12. Pécs, 7643, Hungary
| | - Kázmér Karádi
- Department of Behavioral Sciences, University of Pécs Medical School Szigeti u. 12. Pécs, 7624, Hungary
| | - Katalin Lőrincz
- Department of Neurology, University of Pécs Medical School Rét u. 2. Pécs, 7623, Hungary
| | - Réka Horváth
- Department of Neurology, University of Pécs Medical School Rét u. 2. Pécs, 7623, Hungary
| | - Csilla Gyimesi
- Department of Neurology, University of Pécs Medical School Rét u. 2. Pécs, 7623, Hungary
| | - Cecília Szekeres-Paraczky
- Human Brain Research Laboratory, Institute of Experimental Medicine, ELKH Szigony u. 43. Budapest, 1083, Hungary
| | - Zsolt Horváth
- Department of Neurosurgery, University of Pécs Medical School Rét u. 2. Pécs, 7623, Hungary
| | - József Janszky
- Department of Neurology, University of Pécs Medical School Rét u. 2. Pécs, 7623, Hungary; MTA-PTE Clinical Neuroscience MR Research Group, Center for Neuroscience, University of Pécs Ifjúság u 20. Pécs, 7624, Hungary
| | - Tamás Dóczi
- Department of Neurosurgery, University of Pécs Medical School Rét u. 2. Pécs, 7623, Hungary; MTA-PTE Clinical Neuroscience MR Research Group, Center for Neuroscience, University of Pécs Ifjúság u 20. Pécs, 7624, Hungary
| | - László Seress
- Department of Medical Biology and Central Electron Microscopic Laboratory, University of Pécs Medical School Szigeti u. 12. Pécs, 7643, Hungary; Neuromorphology and Cellular Neurobiology Research Group, Center for Neuroscience, University of Pécs Ifjúság u. 20. Pécs, 7624, Hungary
| | - Hajnalka Ábrahám
- Department of Medical Biology and Central Electron Microscopic Laboratory, University of Pécs Medical School Szigeti u. 12. Pécs, 7643, Hungary; Neuromorphology and Cellular Neurobiology Research Group, Center for Neuroscience, University of Pécs Ifjúság u. 20. Pécs, 7624, Hungary.
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Bryant JE, Lahti AC, Briend F, Kraguljac NV. White Matter Neurometabolic Signatures Support the Deficit and Nondeficit Distinction in Antipsychotic-Naïve First-Episode Psychosis Patients. Schizophr Bull 2021; 47:1068-1076. [PMID: 33693906 PMCID: PMC8266628 DOI: 10.1093/schbul/sbab014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The deficit syndrome is thought to be a more homogenous clinical subgroup within the syndrome of schizophrenia that is characterized by enduring negative symptoms. It is hypothesized that distinct pathophysiological processes underlie the subtypes, where the deficit syndrome reflects an early onset nonprogressive developmental process, and the nondeficit form of the illness is characterized by attenuated neuroplasticity secondary to elevated glutamate levels. We used single-voxel magnetic resonance spectroscopy (PRESS; TE: 30 ms) to measure left frontal white matter neurometabolite levels in 61 antipsychotic-naïve first-episode psychosis patients (39 who did not display deficit features, 22 who did display deficit features, assessed with the Schedule for the Deficit Syndrome) and 59 healthy controls. Metabolite levels were quantified with the LCModel. We used a MANCOVA to determine neurometabolite differences between healthy controls, deficit syndrome patients, and nondeficit patients. We report a significant group difference when all metabolites were considered jointly (F[10,208] = 2.16; P = .02). Post hoc analyses showed that patients presenting without deficit features had higher glutamate levels than patients with deficit features and controls. Patients presenting without deficit features also had significantly higher myoinositol levels than controls; myoinositol levels were trend-level higher in patients presenting with deficit features compared to controls. Our data support the idea that the pathophysiology of patients presenting without deficit features may differ from those presenting with deficit features.
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Affiliation(s)
- James Edward Bryant
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, SC 501, Birmingham, AL, USA
| | - Adrienne Carol Lahti
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, SC 501, Birmingham, AL, USA
| | - Frederic Briend
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, SC 501, Birmingham, AL, USA,UMR1253, iBrain, Université de Tours, Inserm, Tours, France
| | - Nina Vanessa Kraguljac
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, SC 501, Birmingham, AL, USA,To whom correspondence should be addressed; tel: 205-996-7171, e-mail:
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White Matter Interstitial Neurons in the Adult Human Brain: 3% of Cortical Neurons in Quest for Recognition. Cells 2021; 10:cells10010190. [PMID: 33477896 PMCID: PMC7833373 DOI: 10.3390/cells10010190] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 02/03/2023] Open
Abstract
White matter interstitial neurons (WMIN) are a subset of cortical neurons located in the subcortical white matter. Although they were fist described over 150 years ago, they are still largely unexplored and often considered a small, functionally insignificant neuronal population. WMIN are adult remnants of neurons located in the transient fetal subplate zone (SP). Following development, some of the SP neurons undergo apoptosis, and the remaining neurons are incorporated in the adult white matter as WMIN. In the adult human brain, WMIN are quite a large population of neurons comprising at least 3% of all cortical neurons (between 600 and 1100 million neurons). They include many of the morphological neuronal types that can be found in the overlying cerebral cortex. Furthermore, the phenotypic and molecular diversity of WMIN is similar to that of the overlying cortical neurons, expressing many glutamatergic and GABAergic biomarkers. WMIN are often considered a functionally unimportant subset of neurons. However, upon closer inspection of the scientific literature, it has been shown that WMIN are integrated in the cortical circuitry and that they exhibit diverse electrophysiological properties, send and receive axons from the cortex, and have active synaptic contacts. Based on these data, we are able to enumerate some of the potential WMIN roles, such as the control of the cerebral blood flow, sleep regulation, and the control of information flow through the cerebral cortex. Also, there is a number of studies indicating the involvement of WMIN in the pathophysiology of many brain disorders such as epilepsy, schizophrenia, Alzheimer’s disease, etc. All of these data indicate that WMIN are a large population with an important function in the adult brain. Further investigation of WMIN could provide us with novel data crucial for an improved elucidation of the pathophysiology of many brain disorders. In this review, we provide an overview of the current WMIN literature, with an emphasis on studies conducted on the human brain.
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Tsai SH, Tsao CY, Lee LJ. Altered White Matter and Layer VIb Neurons in Heterozygous Disc1 Mutant, a Mouse Model of Schizophrenia. Front Neuroanat 2021; 14:605029. [PMID: 33384588 PMCID: PMC7769951 DOI: 10.3389/fnana.2020.605029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/24/2020] [Indexed: 11/13/2022] Open
Abstract
Increased white matter neuron density has been associated with neuropsychiatric disorders including schizophrenia. However, the pathogenic features of these neurons are still largely unknown. Subplate neurons, the earliest generated neurons in the developing cortex have also been associated with schizophrenia and autism. The link between these neurons and mental disorders is also not well established. Since cortical layer VIb neurons are believed to be the remnant of subplate neurons in the adult rodent brain, in this study, we aimed to examine the cytoarchitecture of neurons in cortical layer VIb and the underlying white matter in heterozygous Disc1 mutant (Het) mice, a mouse model of schizophrenia. In the white matter, the number of NeuN-positive neurons was quite low in the external capsule; however, the density of these cells was found increased (54%) in Het mice compared with wildtype (WT) littermates. The density of PV-positive neurons was unchanged in the mutants. In the cortical layer VIb, the density of CTGF-positive neurons increased (21.5%) in Het mice, whereas the number of Cplx3-positive cells reduced (16.1%) in these mutants, compared with WT mice. Layer VIb neurons can be classified by their morphological characters. The morphology of Type I pyramidal neurons was comparable between genotypes while the dendritic length and complexity of Type II multipolar neurons were significantly reduced in Het mice. White matter neurons and layer VIb neurons receive synaptic inputs and modulate the process of sensory information and sleep/arousal pattern. Aberrances of these neurons in Disc1 mutants implies altered brain functions in these mice.
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Affiliation(s)
- Shin-Hwa Tsai
- School of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Yu Tsao
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan
| | - Li-Jen Lee
- School of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Anatomy and Cell Biology, National Taiwan University, Taipei, Taiwan.,Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan
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Kostović I. The enigmatic fetal subplate compartment forms an early tangential cortical nexus and provides the framework for construction of cortical connectivity. Prog Neurobiol 2020; 194:101883. [PMID: 32659318 DOI: 10.1016/j.pneurobio.2020.101883] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/05/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022]
Abstract
The most prominent transient compartment of the primate fetal cortex is the deep, cell-sparse, synapse-containing subplate compartment (SPC). The developmental role of the SPC and its extraordinary size in humans remain enigmatic. This paper evaluates evidence on the development and connectivity of the SPC and discusses its role in the pathogenesis of neurodevelopmental disorders. A synthesis of data shows that the subplate becomes a prominent compartment by its expansion from the deep cortical plate (CP), appearing well-delineated on MR scans and forming a tangential nexus across the hemisphere, consisting of an extracellular matrix, randomly distributed postmigratory neurons, multiple branches of thalamic and long corticocortical axons. The SPC generates early spontaneous non-synaptic and synaptic activity and mediates cortical response upon thalamic stimulation. The subplate nexus provides large-scale interareal connectivity possibly underlying fMR resting-state activity, before corticocortical pathways are established. In late fetal phase, when synapses appear within the CP, transient the SPC coexists with permanent circuitry. The histogenetic role of the SPC is to provide interactive milieu and capacity for guidance, sorting, "waiting" and target selection of thalamocortical and corticocortical pathways. The new evolutionary role of the SPC and its remnant white matter neurons is linked to the increasing number of associative pathways in the human neocortex. These roles attributed to the SPC are regulated using a spatiotemporal gene expression during critical periods, when pathogenic factors may disturb vulnerable circuitry of the SPC, causing neurodevelopmental cognitive circuitry disorders.
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Affiliation(s)
- Ivica Kostović
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Scientific Centre of Excellence for Basic, Clinical and Translational Neuroscience, Salata 12, 10000 Zagreb, Croatia.
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Kubo KI. Increased densities of white matter neurons as a cross-disease feature of neuropsychiatric disorders. Psychiatry Clin Neurosci 2020; 74:166-175. [PMID: 31788900 DOI: 10.1111/pcn.12962] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 12/12/2022]
Abstract
While neurons of the human cerebral cortex are mainly distributed in the gray matter, the white matter (WM) also contains some excitatory and inhibitory neurons, so-called WM neurons. Studies on the cytoarchitectural alterations in the brains of patients with neuropsychiatric disorders have repeatedly reported increased densities of the WM neurons in a proportion of patients with schizophrenia and autism spectrum disorder. Although some studies have demonstrated increased densities of superficial WM neurons, others have demonstrated increased densities of deep WM neurons and increased WM neuron densities can be considered as one of the cross-disease features of neuropsychiatric disorders. Nevertheless, what actually causes the increase in the densities of the WM neurons still remains under debate, and several hypothetical mechanisms have been proposed. The WM neurons in normal brains are considered as remnants of the subplate neurons, which represent a transient cytoarchitectural zone present during development of the mammalian neocortex; it has been suggested that increased densities of the WM neurons could result from inappropriate apoptosis of the subplate neurons in the brains of patients with neuropsychiatric disorders. On the other hand, recent experimental studies have demonstrated that genetic and environmental factors that enhance the risk of development of neuropsychiatric disorders could cause altered distribution of neurons in the WM. To understand the pathophysiology underlying the increased densities of the WM neurons, it is important to investigate the cellular characteristics of the WM neurons in the brains of both normal subjects and patients with neuropsychiatric disorders.
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Affiliation(s)
- Ken-Ichiro Kubo
- Department of Anatomy, Keio University School of Medicine, Tokyo, Japan.,Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan
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10
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Kirkpatrick B, Gürbüz Oflezer Ö, Delice Arslan M, Hack G, Fernandez-Egea E. An Early Developmental Marker of Deficit versus Nondeficit Schizophrenia. Schizophr Bull 2019; 45:1331-1335. [PMID: 31423529 PMCID: PMC6811833 DOI: 10.1093/schbul/sbz024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
People with schizophrenia and primary negative symptoms (deficit schizophrenia) differ from those without such symptoms (nondeficit schizophrenia) on risk factors, course of illness, other signs and symptoms, treatment response, and biological correlates. These differences suggest that the 2 groups may also have developmental differences. A previous study found that people with schizophrenia have a wider palate than comparison subjects. We tested the hypothesis that those with deficit and nondeficit schizophrenia would differ on palate width. A dentist made blinded measurements of palate shape in deficit (N = 21) and nondeficit (N = 25) patients and control subjects (N = 127), matched for age and gender. The deficit group had significantly wider palates than either nondeficit or control subjects (respective means [standard deviation] 37.5 [3.9], 33.7 [3.1], and 34.0 [2.9]; P < .001 for both deficit/nondeficit and deficit/control comparisons, respective effect sizes 1.08 and 1.01). The nondeficit/control difference in width was not significant (P = .83), and there were no significant group differences in length or depth. The power to detect a nondeficit/control difference in width equal in size to that of the deficit/control difference in width (3.5 mm) was 0.99 and 0.92 for a 2.0-mm difference. This difference in palate width may reflect a divergence in development between deficit and nondeficit patients that occurs by the early second trimester and is consistent with the hypothesis that deficit schizophrenia is a separate disease within the syndrome of schizophrenia.
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Affiliation(s)
- Brian Kirkpatrick
- Department of Psychiatry and Behavioral Sciences, University of Nevada, Reno School of Medicine, Reno, Nevada,To whom correspondence should be addressed; tel: 775-682-8455, fax: 775-784-1428, e-mail:
| | - Özlem Gürbüz Oflezer
- Department of Prosthetic Dentistry, Ministry of Health, Istanbul Bahcelievler Oral and Dental Hospital, Istanbul, Turkey
| | - Mehtap Delice Arslan
- Department of Psychiatry, Bakirkoy Research and Training Hospital for Psychiatry, Neurology and Neurosurgery, Istanbul, Turkey
| | - Gary Hack
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, Maryland
| | - Emilio Fernandez-Egea
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK,Department of Psychiatry and Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK,Centro de Investigación Biomédica en Red, Área de Salud Mental (CIBERSAM), Barcelona, Spain
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11
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Sedmak G, Judaš M. The total number of white matter interstitial neurons in the human brain. J Anat 2019; 235:626-636. [PMID: 31173356 DOI: 10.1111/joa.13018] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2019] [Indexed: 02/06/2023] Open
Abstract
In the adult human brain, the interstitial neurons (WMIN) of the subcortical white matter are the surviving remnants of the fetal subplate zone. It has been suggested that they perform certain important functions and may be involved in the pathogenesis of several neurological and psychiatric disorders. However, many important features of this class of human cortical neurons remain insufficiently explored. In this study, we analyzed the total number, and regional and topological distribution of WMIN in the adult human subcortical white matter, using a combined immunocytochemical (NeuN) and stereological approaches. We found that the average number of WMIN in 1 mm3 of the subcortical white matter is 1.230 ± 549, which translates to the average total number of 593 811 183.6 ± 264 849 443.35 of WMIN in the entire subcortical telencephalic white matter. While there were no significant differences in their regional distribution, the lowest number of WMIN has been consistently observed in the limbic cortex, and the highest number in the frontal cortex. With respect to their topological distribution, the WMIN were consistently more numerous within gyral crowns, less numerous along gyral walls and least numerous at the bottom of cortical sulci (where they occupy a narrow and compact zone below the cortical-white matter border). The topological location of WMIN is also significantly correlated with their morphology: pyramidal and multipolar forms are the most numerous within gyral crowns, whereas bipolar forms predominate at the bottom of cortical sulci. Our results indicate that WMIN represent substantial neuronal population in the adult human cerebral cortex (e.g. more numerous than thalamic or basal ganglia neurons) and thus deserve more detailed morphological and functional investigations in the future.
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Affiliation(s)
- Goran Sedmak
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia.,Center for Excellence in Basic, Clinical and Translational Neuroscience, Zagreb, Croatia
| | - Miloš Judaš
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia.,Center for Excellence in Basic, Clinical and Translational Neuroscience, Zagreb, Croatia
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12
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Serati M, Delvecchio G, Orsenigo G, Mandolini GM, Lazzaretti M, Scola E, Triulzi F, Brambilla P. The Role of the Subplate in Schizophrenia and Autism: A Systematic Review. Neuroscience 2019; 408:58-67. [PMID: 30930130 DOI: 10.1016/j.neuroscience.2019.03.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 03/19/2019] [Accepted: 03/20/2019] [Indexed: 02/07/2023]
Abstract
The subplate (SP) represents a transitory cytoarchitectural fetal compartment containing most subcortical and cortico-cortical afferents, and has a fundamental role in the structural development of the healthy adult brain. There is evidence that schizophrenia and autism may be determined by developmental defects in the cortex or cortical circuitry during the earliest stages of pregnancy. This article provides an overview on fetal SP development, considering its role in schizophrenia and autism, as supported by a systematic review of the main databases. The SP has been described as a cortical amplifier with a role in the coordination of cortical activity, and sensitive growth and migration windows have crucial consequences with respect to cognitive functioning. Although there are not enough studies to draw final conclusions, improved knowledge of the SP's role in schizophrenia and autism spectrum disorders may help to elucidate and possibly prevent the onset of these two severe disorders.
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Affiliation(s)
- Marta Serati
- Department of Mental Health, ASST Rhodense, Rho, Milan, Italy.
| | - Giuseppe Delvecchio
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Giulia Orsenigo
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Italy
| | - Gian Mario Mandolini
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Italy
| | - Matteo Lazzaretti
- Department of Neurosciences and Mental Health, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Italy
| | - Elisa Scola
- Department of Neuroradiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Fabio Triulzi
- Department of Neuroradiology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Paolo Brambilla
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Department of Psychiatry and Behavioural Neurosciences, University of Texas at Houston, TX, USA
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13
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From the microscope to the magnet: Disconnection in schizophrenia and bipolar disorder. Neurosci Biobehav Rev 2019; 98:47-57. [PMID: 30629976 DOI: 10.1016/j.neubiorev.2019.01.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/22/2018] [Accepted: 01/06/2019] [Indexed: 12/15/2022]
Abstract
White matter (WM) abnormalities have implicated schizophrenia (SZ) and bipolar disorder (BD) as disconnection syndromes, yet the extent to which these abnormalities are shared versus distinct remains unclear. Diffusion tensor imaging (DTI) studies yield a putative measure of WM integrity while neuropathological studies provide more specific microstructural information. We therefore systematically reviewed all neuropathological (n = 12) and DTI (n = 11) studies directly comparing patients with SZ and BD. Most studies (18/23) reported no difference between patient groups. Changes in oligodendrocyte density, myelin staining and gene, protein and mRNA expression were found in SZ and/or BD patients as compared to healthy individuals, while DTI studies showed common alterations in thalamic radiations, uncinate fasciculus, corpus callosum, longitudinal fasciculus and corona radiata. Altogether, findings suggest shared disconnectivity in SZ and BD, which are likely related to their considerable overlap. Above all, neuroimaging findings corroborated neuropathological findings in the prefrontal cortex, demonstrating the utility of integrating multiple methodologies. Focusing on clinical dimensions over disease entities will advance our understanding of disconnectivity and help inform preventive medicine.
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Abstract
We previously proposed that people with schizophrenia who have primary, enduring negative symptoms have a disease-deficit schizophrenia (DS)-that is separate from that affecting people with schizophrenia without these features. Additional evidence consistent with the separate disease hypothesis has accumulated in recent years. White matter changes may be widespread in deficit compared to nondeficit patients and may relate to problems in early brain migration. These 2 patient groups also appear to differ on metabolic measures prior to antipsychotic treatment. Studies of reward and defeatist beliefs provide the basis for future treatment trials. The 2 factors or groups within negative symptoms broadly defined (both primary and secondary) have also been found in DS, and recent evidence suggests these 2 symptom groups have different correlates and reflect the existence of 2 groups with in DS. Negative symptoms are found in disorders other than schizophrenia, and excess summer birth, a deficit risk factor, has been found in a non-patient group with deficit-like features. It may be useful in future research to determine whether findings in DS extend to patients with other neuropsychiatric disorders who also have negative symptoms.
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Affiliation(s)
- Brian Kirkpatrick
- Department of Psychiatry and Behavioral Sciences, University of Nevada Reno School of Medicine, Reno, NV
| | - Armida Mucci
- Department of Psychiatry, University of Naples SUN, Naples, Italy
| | - Silvana Galderisi
- Department of Psychiatry, University of Campania Luigi Vanvitelli (SUN); University Hospital SUN, Naples, Italy
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15
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Abstract
Epilepsy is one of the most common neurologic disorders, affecting about 50 million people worldwide. The disease is characterized by recurrent seizures, which are due to aberrant neuronal networks resulting in synchronous discharges. The term epilepsy encompasses a large spectrum of syndromes and diseases with different etiopathogenesis. The recent development of imaging and epilepsy surgery techniques is now enabling the identification of structural abnormalities that are part of the epileptic network, and the removal of these lesions may result in control of seizures. Access of this clinically well-characterized neurosurgical material has provided neuropathologists with the opportunity to study a variety of structural brain abnormalities associated with epilepsy, by combining traditional routine histopathologic methods with molecular genetics and functional analysis of the resected tissue. This approach has contributed greatly to a better diagnosis and classification of these structural lesions, and has provided important new insights into their pathogenesis and epileptogenesis. The present chapter provides a detailed description of the large spectrum of histopathologic findings encountered in epilepsy surgery patients, addressing in particular the nonneoplastic pathologies, including hippocampal sclerosis, malformations of cortical development, Sturge-Weber syndrome, and Rasmussen encephalitis, and reviews current knowledge regarding the underlying molecular pathomechanisms and cellular mechanisms mediating hyperexcitability.
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Affiliation(s)
- Eleonora Aronica
- Department of Neuropathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands; Stichting Epilepsie Instellingen Nederland, the Netherlands.
| | - Angelika Mühlebner
- Department of Neuropathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
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16
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Karlsgodt KH. Diffusion Imaging of White Matter In Schizophrenia: Progress and Future Directions. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2016; 1:209-217. [PMID: 27453952 PMCID: PMC4955654 DOI: 10.1016/j.bpsc.2015.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Diffusion tensor imaging (DTI) is a powerful tool for the in-vivo assessment of white matter microstructure. The application of DTI methodologies to the study of schizophrenia has supported and advanced the hypothesis of schizophrenia as a disorder of disrupted connectivity. In the context of impaired structural connectivity, the extended time frame of white matter development may offer unique opportunities for treatment that can capitalize on the neural flexibility that is still present in the period leading up to and after disease onset. Therefore, it is important to gain a clear understanding of white matter deficits and how they may emerge and change across the illness. However, while there is broad consistency in the findings of white matter deficits in patients with schizophrenia, there is also a great deal of variability in specific findings across studies. In this review, the aim is to move beyond summarizing case-control analyses, to consider the many factors that may impact DTI measures, to explain variability of findings, and to explore future directions for the field. The topics explored include ways to parse DTI patterns associated with different disease subtypes, ways in which novel and established treatments might interact with or enhance white matter, ways of dissociating developmental change from the disease process itself, and understanding the role of emerging analytic methodologies.
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Affiliation(s)
- Katherine H Karlsgodt
- Psychiatry Research Division, Zucker Hillside Hospital and Feinstein Institute for Medical Research; Department of Psychiatry, Hofstra NorthShore LIJ School of Medicine
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17
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Pełka-Wysiecka J, Wroński M, Bieńkowski P, Murawiec S, Samochowiec A, Samochowiec J. Odors identification differences in deficit and nondeficit schizophrenia. Pharmacol Rep 2016; 68:390-5. [DOI: 10.1016/j.pharep.2015.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/05/2015] [Accepted: 11/02/2015] [Indexed: 11/15/2022]
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18
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Halene TB, Kozlenkov A, Jiang Y, Mitchell A, Javidfar B, Dincer A, Park R, Wiseman J, Croxson P, Giannaris EL, Hof PR, Roussos P, Dracheva S, Hemby SE, Akbarian S. NeuN+ neuronal nuclei in non-human primate prefrontal cortex and subcortical white matter after clozapine exposure. Schizophr Res 2016; 170:235-44. [PMID: 26776227 PMCID: PMC4740223 DOI: 10.1016/j.schres.2015.12.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/24/2015] [Accepted: 12/28/2015] [Indexed: 12/01/2022]
Abstract
Increased neuronal densities in subcortical white matter have been reported for some cases with schizophrenia. The underlying cellular and molecular mechanisms remain unresolved. We exposed 26 young adult macaque monkeys for 6 months to either clozapine, haloperidol or placebo and measured by structural MRI frontal gray and white matter volumes before and after treatment, followed by observer-independent, flow-cytometry-based quantification of neuronal and non-neuronal nuclei and molecular fingerprinting of cell-type specific transcripts. After clozapine exposure, the proportion of nuclei expressing the neuronal marker NeuN increased by approximately 50% in subcortical white matter, in conjunction with a more subtle and non-significant increase in overlying gray matter. Numbers and proportions of nuclei expressing the oligodendrocyte lineage marker, OLIG2, and cell-type specific RNA expression patterns, were maintained after antipsychotic drug exposure. Frontal lobe gray and white matter volumes remained indistinguishable between antipsychotic-drug-exposed and control groups. Chronic clozapine exposure increases the proportion of NeuN+ nuclei in frontal subcortical white matter, without alterations in frontal lobe volumes or cell type-specific gene expression. Further exploration of neurochemical plasticity in non-human primate brain exposed to antipsychotic drugs is warranted.
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Affiliation(s)
- Tobias B. Halene
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA,Corresponding author: Tobias B. Halene, MD PhD, Icahn School of Medicine at Mount Sinai, Department of Psychiatry, 1470 Madison Ave, Hess 9-105, New York, NY 10029, Tel: 646 627 5529, Fax: 646-537-9583,
| | - Alexey Kozlenkov
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yan Jiang
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Amanda Mitchell
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Behnam Javidfar
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Aslihan Dincer
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Royce Park
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jennifer Wiseman
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Paula Croxson
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eustathia Lela Giannaris
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Panos Roussos
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA,Department of Genetics and Genomic Science and Institute for Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stella Dracheva
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Scott E. Hemby
- Department of Physiology and Pharmacology, Wake Forest University, Winston-Salem, NC, USA
| | - Schahram Akbarian
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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19
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Iwatani J, Ishida T, Donishi T, Ukai S, Shinosaki K, Terada M, Kaneoke Y. Use of T1-weighted/T2-weighted magnetic resonance ratio images to elucidate changes in the schizophrenic brain. Brain Behav 2015; 5:e00399. [PMID: 26516617 PMCID: PMC4614056 DOI: 10.1002/brb3.399] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 07/27/2015] [Accepted: 08/23/2015] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION One leading hypothesis suggests that schizophrenia (SZ) is a neurodevelopmental disorder caused by genetic defects in association with environmental risk factors that affect synapse and myelin formation. Recent magnetic resonance imaging (MRI) studies of SZ brain showed both gray matter (GM) reduction and white matter (WM) fractional anisotropy reduction. In this study, we used T1-weighted (T1w)/T2-weighted (T2w) MRI ratio images, which increase myelin-related signal contrast and reduce receiver-coil bias. METHODS We measured T1w/T2w ratio image signal intensity in 29 patients with SZ and 33 healthy controls (HCs), and then compared them against bias-corrected T1w images. RESULTS Mean T1w/T2w ratio signal intensity values across all SZ GM and WM voxels were significantly lower than those for the HC values (analysis of covariance with age, gender, handedness, and premorbid intelligence quotient as nuisance covariates). SZ mean WM T1w/T2w ratio values were related to Global Assessment of Functioning (GAF) scores and were inversely related to the positive psychotic symptoms of the Positive and Negative Syndrome Scale. Voxel-based analysis revealed significantly lower T1w/T2w ratio image signal intensity values in the right ventral putamen in SZ GM. T1w image intensities did not differ between the SZ and HC groups. CONCLUSIONS T1-weighted/T2-weighted ratio imaging increased the detectability of SZ pathological changes. Reduced SZ brain signal intensity is likely due to diminished myelin content; therefore, mapping myelin-related SZ brain changes using T1w/T2w ratio images may be useful for studies of SZ brain abnormalities.
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Affiliation(s)
- Jun Iwatani
- Department of Neuropsychiatry Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan
| | - Takuya Ishida
- Department of Neuropsychiatry Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan ; Department of System Neurophysiology Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan
| | - Tomohiro Donishi
- Department of System Neurophysiology Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan
| | - Satoshi Ukai
- Department of Neuropsychiatry Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan
| | - Kazuhiro Shinosaki
- Department of Neuropsychiatry Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan
| | - Masaki Terada
- Wakayama-Minami Radiology Clinic 870-2 Kimiidera Wakayama 641-0012 Japan
| | - Yoshiki Kaneoke
- Department of System Neurophysiology Graduate School of Wakayama Medical University 811-1 Kimiidera Wakayama 641-8509 Japan
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20
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Transcriptional regulation of GAD1 GABA synthesis gene in the prefrontal cortex of subjects with schizophrenia. Schizophr Res 2015; 167:28-34. [PMID: 25458568 PMCID: PMC4417100 DOI: 10.1016/j.schres.2014.10.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 10/08/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022]
Abstract
Expression of GAD1 GABA synthesis enzyme is highly regulated by neuronal activity and reaches mature levels in the prefrontal cortex not before adolescence. A significant portion of cases diagnosed with schizophrenia show deficits in GAD1 RNA and protein levels in multiple areas of adult cerebral cortex, possibly reflecting molecular or cellular defects in subtypes of GABAergic interneurons essential for network synchronization and cognition. Here, we review 20years of progress towards a better understanding of disease-related regulation of GAD1 gene expression. For example, deficits in cortical GAD1 RNA in some cases of schizophrenia are associated with changes in the epigenetic architecture of the promoter, affecting DNA methylation patterns and nucleosomal histone modifications. These localized chromatin defects at the 5' end of GAD1 are superimposed by disordered locus-specific chromosomal conformations, including weakening of long-range promoter-enhancer loopings and physical disconnection of GAD1 core promoter sequences from cis-regulatory elements positioned 50 kilobases further upstream. Studies on the 3-dimensional architecture of the GAD1 locus in neurons, including developmentally regulated higher order chromatin compromised by the disease process, together with exploration of locus-specific epigenetic interventions in animal models, could pave the way for future treatments of psychosis and schizophrenia.
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21
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Lei W, Li N, Deng W, Li M, Huang C, Ma X, Wang Q, Guo W, Li Y, Jiang L, Zhou Y, Hu X, McAlonan GM, Li T. White matter alterations in first episode treatment-naïve patients with deficit schizophrenia: a combined VBM and DTI study. Sci Rep 2015; 5:12994. [PMID: 26257373 PMCID: PMC4530339 DOI: 10.1038/srep12994] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/06/2015] [Indexed: 02/05/2023] Open
Abstract
Categorizing ‘deficit schizophrenia’ (DS) as distinct from ‘non-deficit’ schizophrenia (NDS) may help reduce heterogeneity within schizophrenia. However, it is unknown if DS has a discrete white matter signature. Here we used MRI to compare white matter volume (voxel-based morphometry) and microstructural integrity (fractional anisotropy, FA) in first-episode treatment-naïve patients with DS and NDS and their unaffected relatives to control groups of similar age. We found that white matter disruption was prominent in DS compared to controls; the DS group had lower volumes in the cerebellum, bilateral extra-nuclear and bilateral frontoparietal regions, and lower FA in the body of corpus callosum, posterior superior longitudinal fasciculus and uncinate fasciculus. The DS group also had lower volume in bilateral extra-nuclear regions compared to NDS, and the volume of these clusters was negatively correlated with deficit symptom ratings. NDS patients however, had no significant volume alterations and limited disruption of microstructural integrity compared to controls. Finally, first-degree relatives of those with DS shared volume abnormalities in right extra-nuclear white matter. Thus, white matter pathology in schizophrenia is most evident in the deficit condition, and lower extra-nuclear white matter volumes in both DS patients and their relatives may represent a brain structural ‘endophenotype’ for DS.
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Affiliation(s)
- Wei Lei
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Na Li
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Wei Deng
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Mingli Li
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Chaohua Huang
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Xiaohong Ma
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Qiang Wang
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Wanjun Guo
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Yinfei Li
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Lijun Jiang
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Yi Zhou
- Department of Radiology, Hospital of Chengdu Office of People's Government of Tibetan autonomous Region, Branch Hospital of West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Xun Hu
- Huaxi Biobank, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
| | - Grainne Mary McAlonan
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK
| | - Tao Li
- The Mental Health Center &Psychiatric Laboratory, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu City, Sichuan Province, China
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22
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White matter alterations in first episode treatment-naïve patients with deficit schizophrenia: a combined VBM and DTI study. Sci Rep 2015. [PMID: 26257373 DOI: 10.1038/srep12994.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Categorizing 'deficit schizophrenia' (DS) as distinct from 'non-deficit' schizophrenia (NDS) may help reduce heterogeneity within schizophrenia. However, it is unknown if DS has a discrete white matter signature. Here we used MRI to compare white matter volume (voxel-based morphometry) and microstructural integrity (fractional anisotropy, FA) in first-episode treatment-naïve patients with DS and NDS and their unaffected relatives to control groups of similar age. We found that white matter disruption was prominent in DS compared to controls; the DS group had lower volumes in the cerebellum, bilateral extra-nuclear and bilateral frontoparietal regions, and lower FA in the body of corpus callosum, posterior superior longitudinal fasciculus and uncinate fasciculus. The DS group also had lower volume in bilateral extra-nuclear regions compared to NDS, and the volume of these clusters was negatively correlated with deficit symptom ratings. NDS patients however, had no significant volume alterations and limited disruption of microstructural integrity compared to controls. Finally, first-degree relatives of those with DS shared volume abnormalities in right extra-nuclear white matter. Thus, white matter pathology in schizophrenia is most evident in the deficit condition, and lower extra-nuclear white matter volumes in both DS patients and their relatives may represent a brain structural 'endophenotype' for DS.
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23
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Schmidt MJ, Mirnics K. Neurodevelopment, GABA system dysfunction, and schizophrenia. Neuropsychopharmacology 2015; 40:190-206. [PMID: 24759129 PMCID: PMC4262918 DOI: 10.1038/npp.2014.95] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/03/2014] [Accepted: 04/11/2014] [Indexed: 02/07/2023]
Abstract
The origins of schizophrenia have eluded clinicians and researchers since Kraepelin and Bleuler began documenting their findings. However, large clinical research efforts in recent decades have identified numerous genetic and environmental risk factors for schizophrenia. The combined data strongly support the neurodevelopmental hypothesis of schizophrenia and underscore the importance of the common converging effects of diverse insults. In this review, we discuss the evidence that genetic and environmental risk factors that predispose to schizophrenia disrupt the development and normal functioning of the GABAergic system.
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Affiliation(s)
- Martin J Schmidt
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
| | - Karoly Mirnics
- Department of Psychiatry, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN, USA
- Department of Psychiatry, University of Szeged, Szeged, Hungary
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24
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Mirror neuron dysfunction in schizophrenia and its functional implications: a systematic review. Schizophr Res 2014; 160:9-19. [PMID: 25468183 PMCID: PMC6284797 DOI: 10.1016/j.schres.2014.10.040] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/19/2014] [Accepted: 10/28/2014] [Indexed: 12/25/2022]
Abstract
Dysfunctional mirror neuron activity (MNA) has been posited to underlie diverse symptoms of schizophrenia (e.g., ego-boundary disturbances, negative symptoms, social cognition impairments and catatonic symptoms). In this paper, we systematically review studies that have empirically compared putative MNA in schizophrenia patients and healthy subjects using different neurophysiological probes. Majority of the studies (n=9) reported reduced MNA in patients. Two each reported either increased MNA or mixed (both increased and decreased) results, while only one study reported normal findings. Reduced MNA was associated with greater negative symptoms and theory of mind deficits. The neurophysiological technique, task paradigms used, specific brain regions studied and laterality did not influence these findings. Further, we propose an overarching model to understand the heterogeneous symptom dimensions of schizophrenia, in which an inherent mirror system deficit underlying persistent negative symptoms, social cognition impairments and self-monitoring deficits triggers a pathological metaplastic reorganization of this system resulting in aberrant excessive MNA and the phasic catatonic symptoms, affective instability and hallucinations. Despite being preliminary in nature, evidence of abnormal MNA in schizophrenia reported necessitates more detailed investigation. Future research directions of using this model within the Research Domain Criteria framework of the National Institute of Mental Health are discussed.
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Chen C, Jiang W, Zhong N, Wu J, Jiang H, Du J, Li Y, Ma X, Zhao M, Hashimoto K, Gao C. Impaired processing speed and attention in first-episode drug naive schizophrenia with deficit syndrome. Schizophr Res 2014; 159:478-84. [PMID: 25261044 DOI: 10.1016/j.schres.2014.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 08/11/2014] [Accepted: 09/03/2014] [Indexed: 11/18/2022]
Abstract
Although first-episode drug naive patients with schizophrenia are known to show cognitive impairment, the cognitive performances of these patients, who suffer deficit syndrome, compared with those who suffer non-deficit syndrome is undetermined. The aim of this study was to compare cognitive performances in first-episode drug-naive schizophrenia with deficit syndrome or non-deficit syndrome. First-episode drug naive patients (n=49) and medicated patients (n=108) with schizophrenia, and age, sex, and education matched healthy controls (n=57 for the first-episode group, and n=128 for the medicated group) were enrolled. Patients were divided into deficit or non-deficit syndrome groups, using the Schedule for Deficit Syndrome. Cognitive performance was assessed using the CogState computerized cognitive battery. All cognitive domains in first-episode drug naive and medicated patients showed significant impairment compared with their respective control groups. Furthermore, cognitive performance in first-episode drug naive patients was significantly worse than in medicated patients. Interestingly, the cognitive performance markers of processing speed and attention, in first-episode drug naive patients with deficit syndrome, were both significantly worse than in equivalent patients without deficit syndrome. In contrast, no differences in cognitive performance were found between the two groups of medicated patients. In conclusion, this study found that first-episode drug naive schizophrenia with deficit syndrome showed significantly impaired processing speed and attention, compared with patients with non-deficit syndrome. These findings highlight processing speed and attention as potential targets for pharmacological and psychosocial interventions in first-episode schizophrenia with deficit syndrome, since these domains are associated with social outcomes.
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Affiliation(s)
- Ce Chen
- Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Wenhui Jiang
- Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Na Zhong
- Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jin Wu
- Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Haifeng Jiang
- Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jiang Du
- Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ye Li
- Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiancang Ma
- Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Min Zhao
- Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, China.
| | - Kenji Hashimoto
- Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan.
| | - Chengge Gao
- Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
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Liu JYW, Ellis M, Brooke-Ball H, de Tisi J, Eriksson SH, Brandner S, Sisodiya SM, Thom M. High-throughput, automated quantification of white matter neurons in mild malformation of cortical development in epilepsy. Acta Neuropathol Commun 2014; 2:72. [PMID: 24927775 PMCID: PMC4229809 DOI: 10.1186/2051-5960-2-72] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 06/09/2014] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION In epilepsy, the diagnosis of mild Malformation of Cortical Development type II (mMCD II) predominantly relies on the histopathological assessment of heterotopic neurons in the white matter. The exact diagnostic criteria for mMCD II are still ill-defined, mainly because findings from previous studies were contradictory due to small sample size, and the use of different stains and quantitative systems. Advance in technology leading to the development of whole slide imaging with high-throughput, automated quantitative analysis (WSA) may overcome these differences, and may provide objective, rapid, and reliable quantitation of white matter neurons in epilepsy. This study quantified the density of NeuN immunopositive neurons in the white matter of up to 142 epilepsy and control cases using WSA. Quantitative data from WSA was compared to two other systems, semi-automated quantitation, and the widely accepted method of stereology, to assess the reliability and quality of results from WSA. RESULTS All quantitative systems showed a higher density of white matter neurons in epilepsy cases compared to controls (P = 0.002). We found that, in particular, WSA with user-defined region of interest (manual) was superior in terms of larger sampled size, ease of use, time consumption, and accuracy in region selection and cell recognition compared to other methods. Using results from WSA manual, we proposed a threshold value for the classification of mMCD II, where 78% of patients now classified with mMCD II were seizure-free at the second post-operatively follow up. CONCLUSION This study confirms the potential role of WSA in future quantitative diagnostic histology, especially for the histopathological diagnosis of mMCD.
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Abstract
A selective review of the negative symptoms of schizophrenia is an appropriate article to result from the festschrift honoring William T. Carpenter Jr, as he has made substantial contributions in this area. This review assesses progress in 3 areas in which he has been an important investigator: the distinction between primary vs secondary negative symptoms; the appropriate design for treatment trials; and the nosology of negative symptoms.
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Affiliation(s)
- Brian Kirkpatrick
- *To whom correspondence should be addressed; Department of Psychiatry and Behavioral Sciences, University of Nevada School of Medicine,1664 North Virginia Street, Mail Stop 0354, Reno, NV 89557-0354, US; tel: 775-682-8449, fax: 775-784-1428, e-mail:
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Nenadic I, Yotter RA, Sauer H, Gaser C. Cortical surface complexity in frontal and temporal areas varies across subgroups of schizophrenia. Hum Brain Mapp 2013; 35:1691-9. [PMID: 23813686 DOI: 10.1002/hbm.22283] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 01/09/2013] [Accepted: 02/14/2013] [Indexed: 01/03/2023] Open
Abstract
Schizophrenia is assumed to be a neurodevelopmental disorder, which might involve disturbed development of the cerebral cortex, especially in frontal and medial temporal areas. Based on a novel spherical harmonics approach to measuring complexity of cortical folding, we applied a measure based on fractal dimension (FD) to investigate the heterogeneity of regional cortical surface abnormalities across subgroups of schizophrenia defined by symptom profiles. A sample of 87 patients with DSM-IV schizophrenia was divided into three subgroups (based on symptom profiles) with predominantly negative (n = 31), disorganized (n = 23), and paranoid (n = 33) symptoms and each compared to 108 matched healthy controls. While global FD measures were reduced in the right hemisphere of the negative and paranoid subgroups, regional analysis revealed marked heterogeneity of regional FD alterations. The negative subgroup showed most prominent reductions in left anterior cingulate, superior frontal, frontopolar, as well as right superior frontal and superior parietal cortices. The disorganized subgroup showed reductions in bilateral ventrolateral/orbitofrontal cortices, and several increases in the left hemisphere, including inferior parietal, middle temporal, and midcingulate areas. The paranoid subgroup showed only few changes, including decreases in the right superior parietal and left fusiform region, and increase in the left posterior cingulate cortex. Our findings suggest regional heterogeneity of cortical folding complexity, which might be related to biological subgroups of schizophrenia with differing degrees of altered cortical developmental pathology.
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Affiliation(s)
- Igor Nenadic
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
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Abstract
Between one-third and one-half of the individuals who meet diagnostic criteria for schizophrenia remain actively ill despite optimal pharmacological treatment. These individuals tend to progressively deteriorate in terms of social and vocational functioning despite major public and private investments in their rehabilitation. For patients who do not respond to the first prescribed antipsychotic drug, current clinical practice is to switch to a second and a third drug, and eventually to clozapine, the only antipsychotic drug proven to be effective in treatment-refractory schizophrenia (TRS). Occasionally, two antipsychotics are given concomitantly or psychotropic drugs are added to antipsychotic drugs; however, very few empirical data exist to support this practice. Although there are many exceptions, patients who do not benefit from the first prescribed drug will not benefit from any pharmacological intervention. Therefore, efforts are under way to determine the reason for lack of response to available treatments and devise novel, more effective treatments. To be successful these efforts must result in a more specific definition of TRS, as well as in a better understanding of the illness pathophysiology and the mechanism of action of the drugs.
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Affiliation(s)
- Asaf Caspi
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Dorsolateral prefrontal cortex volume in patients with deficit or nondeficit schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2012; 37:264-9. [PMID: 22349577 DOI: 10.1016/j.pnpbp.2012.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/30/2012] [Accepted: 02/05/2012] [Indexed: 12/28/2022]
Abstract
Deficit schizophrenia (DS) represents a promising putative clinical subtype of schizophrenia and is characterized by the presence of primary and enduring negative symptoms. Previous studies have often reported a reduced amount of gray matter within prefrontal and temporal cortices in schizophrenia subjects with prevailing negative symptoms; however, the evidence concerning brain structural abnormalities in patients with DS remains controversial. The aim of the present study was to investigate whether patients with DS differed from those with nondeficit schizophrenia (NDS) with respect to the volume of the dorsolateral prefrontal cortex (DLPFC) and hippocampus, two brain areas considered as key regions in the pathogenesis of schizophrenia. In the present study a 3D-T1w MR imaging procedure and an extensive clinical assessment was carried out in 18 patients with schizophrenia, (10 DS and 8 NDS). 3D MPRAGE images were preprocessed with SPM software and two regions of interest (hippocampus and DLPFC) were manually traced to obtain their gray matter volumes. We found a significant reduction of DLPFC in the entire schizophrenia group, with respect to healthy subjects. Although the subgroup of patients with DS had a more severe clinical picture and more impaired social functioning, the DLPFC volume reduction was greater in NDS than in DS patients. In conclusion, according to our structural neuroimaging findings, DS patients, although characterized by a more severe clinical picture and a worse outcome, show less neurobiological abnormalities.
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Karlsgodt KH, Jacobson SC, Seal M, Fusar-Poli P. The relationship of developmental changes in white matter to the onset of psychosis. Curr Pharm Des 2012; 18:422-33. [PMID: 22239573 PMCID: PMC7130450 DOI: 10.2174/138161212799316073] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 10/17/2011] [Indexed: 12/17/2022]
Abstract
Schizophrenia is a disorder with a pronounced developmental component. Accordingly, there is a growing interest in characterizing developmental changes in the period leading up to disease onset, in an effort to develop effective preventative interventions. One of the ongoing neurodevelopmental changes known to occur in the late adolescent period that often overlaps with the prodromal phase and time of onset is white matter development and myelination. In this critical review, a disruption in the normal trajectory of white matter development could potentially play an important role in the onset of psychosis. We seek to summarize the existing state of research on white matter development in prodromal subjects, with a particular focus on diffusion tensor imaging (DTI) measures. First, we describe the physiological basis of developmental white matter changes and myelination. Next, we characterize the pattern of white matter changes associated with typical development across adolescence as measured with DTI. Then, we discuss white matter changes observed in adult patients with schizophrenia and in individuals seen in genetic and clinical high risk states. Finally, we discuss the implications of these findings for future research directions and for potential therapeutic interventions.
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Affiliation(s)
- Katherine H Karlsgodt
- Semel Institute for Neuroscience and Behavior, University of California, Los Angeles, CA, USA.
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García-Marín V, Blazquez-Llorca L, Rodriguez JR, Gonzalez-Soriano J, DeFelipe J. Differential distribution of neurons in the gyral white matter of the human cerebral cortex. J Comp Neurol 2011; 518:4740-59. [PMID: 20963826 DOI: 10.1002/cne.22485] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The neurons in the cortical white matter (WM neurons) originate from the first set of postmitotic neurons that migrates from the ventricular zone. In particular, they arise in the subplate that contains the earliest cells generated in the telencephalon, prior to the appearance of neurons in gray matter cortical layers. These cortical WM neurons are very numerous during development, when they are thought to participate in transient synaptic networks, although many of these cells later die, and relatively few cells survive as WM neurons in the adult. We used light and electron microscopy to analyze the distribution and density of WM neurons in various areas of the adult human cerebral cortex. Furthermore, we examined the perisomatic innervation of these neurons and estimated the density of synapses in the white matter. Finally, we examined the distribution and neurochemical nature of interneurons that putatively innervate the somata of WM neurons. From the data obtained, we can draw three main conclusions: first, the density of WM neurons varies depending on the cortical areas; second, calretinin-immunoreactive neurons represent the major subpopulation of GABAergic WM neurons; and, third, the somata of WM neurons are surrounded by both glutamatergic and GABAergic axon terminals, although only symmetric axosomatic synapses were found. By contrast, both symmetric and asymmetric axodendritic synapses were observed in the neuropil. We discuss the possible functional implications of these findings in terms of cortical circuits.
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Affiliation(s)
- V García-Marín
- Laboratorio de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain.
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Karlsgodt KH, Bachman P, Winkler AM, Bearden CE, Glahn DC. Genetic influence on the working memory circuitry: behavior, structure, function and extensions to illness. Behav Brain Res 2011; 225:610-22. [PMID: 21878355 DOI: 10.1016/j.bbr.2011.08.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/07/2011] [Indexed: 10/17/2022]
Abstract
Working memory is a highly heritable complex cognitive trait that is critical for a number of higher-level functions. However, the neural substrates of this behavioral phenotype are intricate and it is unknown through what precise biological mechanism variation in working memory is transmitted. In this review we explore different functional and structural components of the working memory circuitry, and the degree to which each of them is contributed to by genetic factors. Specifically, we consider dopaminergic function, glutamatergic function, white matter integrity and gray matter structure all of which provide potential mechanisms for the inheritance of working memory deficits. In addition to discussing the overall heritability of these measures we also address specific genes that may play a role. Each of these heritable components has the potential to uniquely contribute to the working memory deficits observed in genetic disorders, including 22q deletion syndrome, fragile X syndrome, phenylketonuria (PKU), and schizophrenia. By observing the individual contributions of disruptions in different components of the working memory circuitry to behavioral performance, we highlight the concept that there may be many routes to a working memory deficit; even though the same cognitive measure may be a valid endophenotype across different disorders, the underlying cause of, and treatment for, the deficit may differ. This has implications for our understanding of the transmission of working memory deficits in both healthy and disordered populations.
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Affiliation(s)
- Katherine H Karlsgodt
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, Los Angeles, CA, USA.
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Berretta S. Extracellular matrix abnormalities in schizophrenia. Neuropharmacology 2011; 62:1584-97. [PMID: 21856318 DOI: 10.1016/j.neuropharm.2011.08.010] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/05/2011] [Accepted: 08/08/2011] [Indexed: 02/06/2023]
Abstract
Emerging evidence points to the involvement of the brain extracellular matrix (ECM) in the pathophysiology of schizophrenia (SZ). Abnormalities affecting several ECM components, including Reelin and chondroitin sulfate proteoglycans (CSPGs), have been described in subjects with this disease. Solid evidence supports the involvement of Reelin, an ECM glycoprotein involved in corticogenesis, synaptic functions and glutamate NMDA receptor regulation, expressed prevalently in distinct populations of GABAergic neurons, which secrete it into the ECM. Marked changes of Reelin expression in SZ have typically been reported in association with GABA-related abnormalities in subjects with SZ and bipolar disorder. Recent findings from our group point to substantial abnormalities affecting CSPGs, a main ECM component, in the amygdala and entorhinal cortex of subjects with schizophrenia, but not bipolar disorder. Striking increases of glial cells expressing CSPGs were accompanied by reductions of perineuronal nets, CSPG- and Reelin-enriched ECM aggregates enveloping distinct neuronal populations. CSPGs developmental and adult functions, including neuronal migration, axon guidance, synaptic and neurotransmission regulation are highly relevant to the pathophysiology of SZ. Together with reports of anomalies affecting several other ECM components, these findings point to the ECM as a key component of the pathology of SZ. We propose that ECM abnormalities may contribute to several aspects of the pathophysiology of this disease, including disrupted connectivity and neuronal migration, synaptic anomalies and altered GABAergic, glutamatergic and dopaminergic neurotransmission.
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Affiliation(s)
- Sabina Berretta
- Translational Neuroscience Laboratory, Mclean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
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35
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Keller WR, Fischer BA, Carpenter WT. Revisiting the diagnosis of schizophrenia: where have we been and where are we going? CNS Neurosci Ther 2011; 17:83-8. [PMID: 21199450 PMCID: PMC6493851 DOI: 10.1111/j.1755-5949.2010.00229.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Appropriate and reliable classification of mental illness is crucial for advancing the field of psychiatry as agreement on diagnosis has broad implications for treatment of mental disorders and research into the etiopathophysiology of mental disorders. Since schizophrenia was first recognized by Kraepelin (as dementia praecox), there has been much discussion about what does and does not diagnostically constitute the disorder. The importance placed upon different symptoms and course types associated with schizophrenia has been as heterogeneous as the disorder itself. This article focuses upon the classification of schizophrenia over the last 100 years, the current diagnosis of schizophrenia, changes for schizophrenia planned in the upcoming DSM 5, future directions for improving the diagnosis of schizophrenia, and the implications of a new diagnostic paradigm for the illness.
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Affiliation(s)
- William R Keller
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA
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Somerville SM, Conley RR, Roberts RC. Mitochondria in the striatum of subjects with schizophrenia. World J Biol Psychiatry 2011; 12:48-56. [PMID: 20698738 DOI: 10.3109/15622975.2010.505662] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Schizophrenia is a severe mental illness that manifests pathology in many brain regions, including the striatum. Among the abnormalities in schizophrenia are those related to mitochondria. The present study sought to determine whether the number of mitochondria was affected at the level of the synapse. METHODS Human postmortem striatum from schizophrenia subjects and controls was examined at the ultrastructural level. The density of mitochondria and synapses were tabulated using stereology. RESULTS There were similar overall numbers of mitochondria in the caudate nucleus and putamen of schizophrenia subjects vs. controls, but a differential distribution of existing mitochondria. Schizophrenia subjects had 26?30% fewer mitochondria per synapse compared to controls. This may contribute to the pathophysiology of the illness, may be a medication effect, or an adaptive response to normalize the high number of striatal synapses we have previously found. The higher density of mitochondria in dendrites in the caudate nucleus in certain subgroups of schizophrenia vs. controls (>34%) may be related to more synaptic inputs. CONCLUSIONS The role of mitochondria in the various symptoms of schizophrenia is still unclear. A comparison of schizophrenia subjects with differing symptoms or treatment response might shed light on whether differences in mitochondrial density are abnormal or adaptive.
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Affiliation(s)
- Shahza M Somerville
- Neuroscience and Cognitive Sciences, University of Maryland, Baltimore County, Catonsville, MD, USA
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Abstract
The developing mammalian cerebral cortex contains a distinct class of cells, subplate neurons (SPns), that play an important role during early development. SPns are the first neurons to be generated in the cerebral cortex, they reside in the cortical white matter, and they are the first to mature physiologically. SPns receive thalamic and neuromodulatory inputs and project into the developing cortical plate, mostly to layer 4. Thus SPns form one of the first functional cortical circuits and are required to relay early oscillatory activity into the developing cortical plate. Pathophysiological impairment or removal of SPns profoundly affects functional cortical development. SPn removal in visual cortex prevents the maturation of thalamocortical synapses, the maturation of inhibition in layer 4, the development of orientation selective responses and the formation of ocular dominance columns. SPn removal also alters ocular dominance plasticity during the critical period. Therefore, SPns are a key regulator of cortical development and plasticity. SPns are vulnerable to injury during prenatal stages and might provide a crucial link between brain injury in development and later cognitive malfunction.
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Affiliation(s)
- Patrick O Kanold
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA.
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38
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Yang Y, Fung SJ, Rothwell A, Tianmei S, Weickert CS. Increased interstitial white matter neuron density in the dorsolateral prefrontal cortex of people with schizophrenia. Biol Psychiatry 2011; 69:63-70. [PMID: 20974464 PMCID: PMC3005941 DOI: 10.1016/j.biopsych.2010.08.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 08/04/2010] [Accepted: 08/05/2010] [Indexed: 11/27/2022]
Abstract
BACKGROUND Interstitial white matter neurons (IWMNs) may reflect immature neurons that migrate tangentially to the neocortex from the ganglionic eminence to form cortical interneurons. Alterations of interneuron markers have been detected in gray matter of dorsolateral prefrontal cortex in schizophrenia, and IWMNs are also reported to be altered in schizophrenia. In this study, we considered whether a potential link exists between these two pathological findings. METHODS From a cohort of 29 schizophrenia subjects and 37 control subjects, IWMN densities were determined in the dorsolateral prefrontal cortex by counting neuronal nuclear antigen (NeuN) and somatostatin (SST)-positive cells. Double-label immunofluorescence was carried out to determine the overlap between SST+/NeuN+ and SST+/neuropeptide Y + neurons. RESULTS We found that density of NeuN + IWMNs in superficial white matter is significantly increased in schizophrenia subjects compared with control subjects. There was a significant negative correlation between SST mRNA expression in gray matter and NeuN + IWMN density. In schizophrenic patients with increased NeuN IWMN density, the density of SST-expressing neurons in white matter was also higher compared with control subjects. A subpopulation of SST immunopositive cells also show coexpression of neuropeptide Y. CONCLUSIONS Our study confirmed previous results indicating that the density of NeuN + IWMNs is increased in superficial white matter in schizophrenia. We provide the first evidence that increased IWMN density correlates with a gray matter interneuron deficit, suggesting that migration of interneurons from white matter to the cortex may be deficient in some patients with schizophrenia, consistent with an interneuron deficit in schizophrenia.
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Affiliation(s)
- Yang Yang
- Schizophrenia Research Institute, Sydney, NSW, Australia
,School of Psychiatry University of New South Wales, Sydney, NSW, Australia
,Neuroscience Research Australia, Sydney, NSW, Australia
,Peking University Institute of Mental Health, Beijing, China
| | - Samantha J Fung
- Schizophrenia Research Institute, Sydney, NSW, Australia
,Neuroscience Research Australia, Sydney, NSW, Australia
,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
,Corresponding Author: Dr Samantha Fung, Schizophrenia Research Laboratory, Neuroscience Research Australia, Corner of Barker and Easy Streets, Randwick, NSW 2031 Australia, Phone: +61 02 9399 1141, Fax: +61 02 9399 1005,
| | - Alice Rothwell
- Schizophrenia Research Institute, Sydney, NSW, Australia
,School of Psychiatry University of New South Wales, Sydney, NSW, Australia
,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Si Tianmei
- Peking University Institute of Mental Health, Beijing, China
| | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney, NSW, Australia
,School of Psychiatry University of New South Wales, Sydney, NSW, Australia
,Neuroscience Research Australia, Sydney, NSW, Australia
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Judaš M, Sedmak G, Pletikos M. Early history of subplate and interstitial neurons: from Theodor Meynert (1867) to the discovery of the subplate zone (1974). J Anat 2010; 217:344-67. [PMID: 20979585 PMCID: PMC2992413 DOI: 10.1111/j.1469-7580.2010.01283.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2010] [Indexed: 12/29/2022] Open
Abstract
In this historical review, we trace the early history of research on the fetal subplate zone, subplate neurons and interstitial neurons in the white matter of the adult nervous system. We arrive at several general conclusions. First, a century of research clearly testifies that interstitial neurons, subplate neurons and the subplate zone were first observed and variously described in the human brain - or, in more general terms, in large brains of gyrencephalic mammals, characterized by an abundant white matter and slow and protracted prenatal and postnatal development. Secondly, the subplate zone cannot be meaningfully defined using a single criterion - be it a specific population of cells, fibres or a specific molecular or genetic marker. The subplate zone is a highly dynamic architectonic compartment and its size and cellular composition do not remain constant during development. Thirdly, it is important to make a clear distinction between the subplate zone and the subplate (and interstitial) neurons. The transient existence of the subplate zone (as a specific architectonic compartment of the fetal telencephalic wall) should not be equated with the putative transient existence of subplate neurons. It is clear that in rodents, and to an even greater extent in humans and monkeys, a significant number of subplate cells survive and remain functional throughout life.
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Affiliation(s)
- Miloš Judaš
- University of Zagreb School of Medicine, Croatian Institute for Brain Research, Salata 12, Zagreb, Croatia.
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Kostović I, Judaš M, Sedmak G. Developmental history of the subplate zone, subplate neurons and interstitial white matter neurons: relevance for schizophrenia. Int J Dev Neurosci 2010; 29:193-205. [PMID: 20883772 DOI: 10.1016/j.ijdevneu.2010.09.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 09/18/2010] [Accepted: 09/20/2010] [Indexed: 12/22/2022] Open
Abstract
The subplate zone is a transient cytoarchitectonic compartment of the fetal telencephalic wall and contains a population of subplate neurons which are the main neurons of the fetal neocortex and play a key role in normal development of cerebral cortical structure and connectivity. While the subplate zone disappears during the perinatal and early postnatal period, numerous subplate neurons survive and remain embedded in the superficial (gyral) white matter of adolescent and adult brain as so-called interstitial neurons. In both fetal and adult brain, subplate/interstitial neurons belong to two major classes of cortical cells: (a) projection (glutamatergic) neurons and (b) local circuit (GABAergic) interneurons. As interstitial neurons remain strategically positioned at the cortical/white matter interface through which various cortical afferent systems enter the deep cortical layers, they probably serve as auxiliary interneurons involved in differential "gating" of cortical input systems. It is widely accepted that prenatal lesions which alter the number of surviving subplate neurons (i.e., the number of interstitial neurons) and/or the nature of their involvement in cortical circuitry represent an important causal factor in pathogenesis of at least some types of schizophrenia--e.g., in the subgroup of patients with cognitive impairment and deficits of frontal lobe functions. The abnormal functioning of cortical circuitry in schizophrenia becomes manifest during the adolescence, when there is an increased demand for proper functioning of the prefrontal cortex. In this review, we describe developmental history of subplate zone, subplate neurons and surviving interstitial neurons, as well as presumed consequences of the increased number of GABAergic interstitial neurons in the prefrontal cortex. We propose that the increased number of GABAergic interstitial neurons leads to the increased inhibition of prefrontal cortical neurons. This inhibitory action of GABAergic interstitial neurons is facilitated by their strategic position at the cortical/white matter interface where limbic and modulatory afferent pathways enter the prefrontal cortex. Thus, enlarged population of inhibitory interstitial neurons (even if they represent a minor fraction of total neuron number, as in the cerebral cortex itself) may alter the differential "gating" of limbic and modulatory inputs (as well as other cortical and subcortical inputs) and cause a functional disconnectivity between the prefrontal and limbic cortex in the adolescent brain. In conclusion, fetal subplate neurons and surviving postnatal interstitial neurons are important modulators of cortical functions in both normal and schizophrenic cerebral cortex.
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Affiliation(s)
- Ivica Kostović
- Section of Developmental Neuroscience, Croatian Institute for Brain Research, Department of Neuroscience, University of Zagreb School of Medicine, Šalata 12, 10000 Zagreb, Croatia.
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White matter neuron alterations in schizophrenia and related disorders. Int J Dev Neurosci 2010; 29:325-34. [PMID: 20691252 DOI: 10.1016/j.ijdevneu.2010.07.236] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/23/2010] [Accepted: 07/26/2010] [Indexed: 12/15/2022] Open
Abstract
Increased density and altered spatial distribution of subcortical white matter neurons (WMNs) represents one of the more well replicated cellular alterations found in schizophrenia and related disease. In many of the affected cases, the underlying genetic risk architecture for these WMN abnormalities remains unknown. Increased density of neurons immunoreactive for Microtubule-Associated Protein 2 (MAP2) and Neuronal Nuclear Antigen (NeuN) have been reported by independent studies, though there are negative reports as well; additionally, group differences in some of the studies appear to be driven by a small subset of cases. Alterations in markers for inhibitory (GABAergic) neurons have also been described. For example, downregulation of neuropeptide Y (NPY) and nitric oxide synthase (NOS1) in inhibitory WMN positioned at the gray/white matter border, as well as altered spatial distribution, have been reported. While increased density of WMN has been suggested to reflect disturbance of neurodevelopmental processes, including neuronal migration, neurogenesis, and cell death, alternative hypotheses--such as an adaptive response to microglial activation in mature CNS, as has been described in multiple sclerosis--should also be considered. We argue that larger scale studies involving hundreds of postmortem specimens will be necessary in order to clearly establish the subset of subjects affected. Additionally, these larger cohorts could make it feasible to connect the cellular pathology to environmental and genetic factors implicated in schizophrenia, bipolar disorder, and autism. These could include the 22q11 deletion (Velocardiofacial/DiGeorge) syndrome, which in some cases is associated with neuronal ectopias in white matter.
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Association between myelin basic protein expression and left entorhinal cortex pre-alpha cell layer disorganization in schizophrenia. Brain Res 2009; 1301:126-34. [DOI: 10.1016/j.brainres.2009.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 09/02/2009] [Accepted: 09/03/2009] [Indexed: 11/19/2022]
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Luhmann HJ, Kilb W, Hanganu-Opatz IL. Subplate cells: amplifiers of neuronal activity in the developing cerebral cortex. Front Neuroanat 2009; 3:19. [PMID: 19862346 PMCID: PMC2766272 DOI: 10.3389/neuro.05.019.2009] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 09/04/2009] [Indexed: 02/04/2023] Open
Abstract
Due to their unique structural and functional properties, subplate cells are ideally suited to function as important amplifying units within the developing neocortical circuit. Subplate neurons have extensive dendritic and axonal ramifications and relatively mature functional properties, i.e. their action potential firing can exceed frequencies of 40 Hz. At earliest stages of corticogenesis subplate cells receive functional synaptic inputs from the thalamus and from other cortical and non-cortical sources. Glutamatergic and depolarizing GABAergic inputs arise from cortical neurons and neuromodulatory inputs arise from the basal forebrain and other sources. Activation of postsynaptic metabotropic receptors, i.e. muscarinic receptors, elicits in subplate neurons oscillatory burst discharges which are transmitted via electrical and chemical synapses to neighbouring subplate cells and to immature neurons in the cortical plate. The tonic non-synaptic release of GABA from GABAergic subplate cells facilitates the generation of burst discharges. These cellular bursts are amplified by prominent gap junction coupling in the subplate and cortical plate, thereby eliciting 10–20 Hz oscillations in a local columnar network. Thus, we propose that neuronal networks are organized at earliest stages in a gap junction coupled columnar syncytium. We postulate that the subplate does not only serve as a transient relay station for afferent inputs, but rather as an active element amplifying the afferent and intracortical activity.
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Affiliation(s)
- Heiko J Luhmann
- Institute of Physiology and Pathophysiology, University Medical Center, Johannes Gutenberg University Mainz Mainz, Germany
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Clancy B, Teague-Ross TJ, Nagarajan R. Cross-species analyses of the cortical GABAergic and subplate neural populations. Front Neuroanat 2009; 3:20. [PMID: 19936319 PMCID: PMC2779099 DOI: 10.3389/neuro.05.020.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 09/04/2009] [Indexed: 01/26/2023] Open
Abstract
Cortical GABAergic (gamma-aminobutyric acidergic) neurons include a recently identified subset whose projections extend over relatively long distances in adult rodents and primates. A number of these inhibitory projection neurons are located in and above the conventionally identified white matter, suggesting their persistence from, or a correspondence with, the developmental subplate. GABAergic and subplate neurons share some unique properties unlike those of the more prevalent pyramidal neurons. To better understand the GABAergic and subplate populations, we constructed a database of neural developmental events common to the three species most frequently used in experimental studies: rat, mouse, and macaque, using data from the online database www.translatingtime.net as well as GABAergic and subplate developmental data from the empirical literature. We used a general linear model to test for similarities and differences, a valid approach because the sequence of most neurodevelopmental events is remarkably conserved across mammalian species. Similarities between the two rodent populations are striking, permitting us to identify developmental dates for GABAergic and subplate neural events in rats that were previously identified only in mice, as well as the timing in mouse development for events previously identified in rats. Primate comparative data are also compelling, although slight variability in statistical error measurement indicates differences in primate GABAergic and subplate events when compared to rodents. Although human extrapolations are challenging because fewer empirical data points are available, and because human data display more variability, we also produce estimates of dates for GABAergic and subplate neural events that have not yet been, or cannot be, determined empirically in humans.
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Affiliation(s)
- Barbara Clancy
- Department of Biology, University of Central Arkansas Conway, AR, USA
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Connor CM, Guo Y, Akbarian S. Cingulate white matter neurons in schizophrenia and bipolar disorder. Biol Psychiatry 2009; 66:486-93. [PMID: 19559403 PMCID: PMC2725195 DOI: 10.1016/j.biopsych.2009.04.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Revised: 04/27/2009] [Accepted: 04/29/2009] [Indexed: 12/16/2022]
Abstract
BACKGROUND Increased neuronal density in prefrontal, parietal, and temporal white matter of schizophrenia subjects is thought to reflect disordered neurodevelopment; however, it is not known if this cellular alteration affects the cingulate cortex and whether similar changes exist in bipolar disorder. METHOD Eighty-two postmortem specimens (bipolar 15, schizophrenia 22, control 45) were included in this clinical study. Densities for two neuronal markers, neuron-specific nuclear protein (NeuN) and neuregulin 1 alpha (NRG), were determined in white matter up to 2.5 mm beneath the anterior cingulate cortex; density of NeuN immunopositive neurons (NeuN+) was also determined for a subset of cases in prefrontal cortex. Changes during normal development were monitored in a separate cohort of 14 brains. RESULTS Both the schizophrenia and bipolar cohorts demonstrated a twofold increase in NeuN+ density in cingulate white matter; this effect could be attributed to approximately 25% of cases that exceeded the second standard deviation from control subjects. Similar changes were observed in prefrontal cortex. In contrast density of NRG expressing neurons was unaltered. Cases with increased NeuN+ densities in two-dimensional (2-D) counts also showed a pronounced, > fivefold elevation in NeuN+ nuclei per cubic millimeter. Additionally, the developmental cohort demonstrated a 75% decline in NeuN+ neuronal density during the first postnatal year but was stable thereafter. CONCLUSIONS Increased neuronal density in white matter of cingulate cortex in schizophrenia provides further evidence that this alteration occurs in multiple cortical areas. Similar changes in some cases with bipolar illness suggest that the two disorders may share a common underlying defect in late prenatal or early postnatal neurodevelopment.
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Affiliation(s)
- Caroline M. Connor
- Program in Neurobiology, Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester MA 01604, Department of Psychiatry, University of Massachusetts Medical School, Worcester MA 01604
| | - Yin Guo
- Department of Psychiatry, University of Massachusetts Medical School, Worcester MA 01604
| | - Schahram Akbarian
- Department of Psychiatry, University of Massachusetts Medical School, Worcester MA 01604,corresponding author: Schahram Akbarian, Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, 303 Belmont Street, University of Massachusetts Medical School, Worcester MA 01604, , Phone 508 8562674 Fax 508 8563937
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Abstract
Kraepelin proposed dementia praecox and manic-depressive illness as the two major psychotic disorders. This paradigm is still prevalent, but observations of overlapping boundaries between bipolar disorder and schizophrenia challenge this dichotomy. However, the concept of schizophrenia has been radically altered from the original Kraepelinian proposal. We defend the two psychoses positions, but suggest two flaws in the heuristic application: (1) overlapping features, such as psychotic symptoms, are not decisive in differential diagnosis; and (2) each disorder is a syndrome, not a disease entity. An alternative paradigm based on domains of pathology is more powerful for studies of etiology, pathophysiology, and therapeutic discovery.
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Mice with altered myelin proteolipid protein gene expression display cognitive deficits accompanied by abnormal neuron-glia interactions and decreased conduction velocities. J Neurosci 2009; 29:8363-71. [PMID: 19571127 DOI: 10.1523/jneurosci.3216-08.2009] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Conduction velocity (CV) of myelinated axons has been shown to be regulated by oligodendrocytes even after myelination has been completed. However, how myelinating oligodendrocytes regulate CV, and what the significance of this regulation is for normal brain function remain unknown. To address these questions, we analyzed a transgenic mouse line harboring extra copies of the myelin proteolipid protein 1 (plp1) gene (plp1(tg/-) mice) at 2 months of age. At this stage, the plp1(tg/-) mice have an unaffected myelin structure with a normally appearing ion channel distribution, but the CV in all axonal tracts tested in the CNS is greatly reduced. We also found decreased axonal diameters and slightly abnormal paranodal structures, both of which can be a cause for the reduced CV. Interestingly the plp1(tg/-) mice showed altered anxiety-like behaviors, reduced prepulse inhibitions, spatial learning deficits and working memory deficit, all of which are schizophrenia-related behaviors. Our results implicate that abnormalities in the neuron-glia interactions at the paranodal junctions can result in reduced CV in the CNS, which then induces behavioral abnormalities related to schizophrenia.
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Roberts RC, Roche JK, Conley RR, Lahti AC. Dopaminergic synapses in the caudate of subjects with schizophrenia: relationship to treatment response. Synapse 2009; 63:520-30. [PMID: 19226604 DOI: 10.1002/syn.20623] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The typical symptoms of schizophrenia (SZ) are psychotic symptoms (hallucinations, delusions, disorders of thought or speech, grossly disorganized behavior) as well as cognitive impairments and negative symptoms. Not all patients respond to treatment and in those who do, only psychotic symptoms are usually improved. Imaging studies have shown that SZ subjects with high striatal dopamine release are far more responsive to antipsychotic drugs than those patients who have dopamine levels lower than or comparable to that of normal controls. In the present study we hypothesized that there was a link between psychosis and the number of dopaminergic synapses in the caudate nucleus in SZ. We examined dopaminergic synapses at the electron microscopic level in postmortem caudate from cases obtained from the Maryland Brain Collection. SZs were subdivided based on treatment response or resistance. The tissue was processed for the immunocytochemical localization of tyrosine hydroxylase (TH), the synthesizing enzyme for dopamine, and prepared for electron microscopy. The density of all TH labeled synapses was 43% greater in treatment responders than in controls and 62% greater in than in treatment resistant SZ. Axodendritic, but not axospinous, TH-labeled synapses showed this increase. TH-labeled axodendritic synapses in treatment responders were elevated in density (1.95 +/- 0.093/10 microm(3)) compared to treatment resistant SZ (0.04 +/- 0.017/10 microm(3)) and controls (0.11 +/- 0.044/10 microm(3)). The results of the present study suggest that one anatomical underpinning of good treatment response may be a higher density of dopaminergic synapses and support a biological basis to treatment response and resistance. Moreover, these data have important implications for linking specific neuropathology with particular symptoms.
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Affiliation(s)
- Rosalinda C Roberts
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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Galderisi S, Maj M. Deficit schizophrenia: an overview of clinical, biological and treatment aspects. Eur Psychiatry 2009; 24:493-500. [PMID: 19553087 DOI: 10.1016/j.eurpsy.2009.03.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 03/18/2009] [Accepted: 03/19/2009] [Indexed: 10/20/2022] Open
Abstract
The concept of deficit schizophrenia is regarded as one of the most promising attempts to reduce heterogeneity within schizophrenia. This paper summarizes the clinical, neurocognitive, brain imaging and electrophysiological correlates of this subtype of schizophrenia. Attempts to identify genetic and non-genetic risk factors are reviewed. Methodological limitations of studies supporting the efficacy of atypical antipsychotics in the treatment of the syndrome are highlighted. Two decades of research on deficit schizophrenia have failed to prove that it represents the extreme end of a severity continuum in schizophrenia, while some findings support the claim that it may be a separate disease entity.
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Affiliation(s)
- S Galderisi
- Department of Psychiatry, Medical School, University of Naples SUN, Largo Madonna delle Grazie, Naples, Italy.
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Suárez-Solá ML, González-Delgado FJ, Pueyo-Morlans M, Medina-Bolívar OC, Hernández-Acosta NC, González-Gómez M, Meyer G. Neurons in the white matter of the adult human neocortex. Front Neuroanat 2009; 3:7. [PMID: 19543540 PMCID: PMC2697018 DOI: 10.3389/neuro.05.007.2009] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 05/23/2009] [Indexed: 11/13/2022] Open
Abstract
The white matter (WM) of the adult human neocortex contains the so-called “interstitial neurons”. They are most numerous in the superficial WM underlying the cortical gyri, and decrease in density toward the deep WM. They are morphologically heterogeneous. A subgroup of interstitial neurons display pyramidal-cell like morphologies, characterized by a polarized dendritic tree with a dominant apical dendrite, and covered with a variable number of dendritic spines. In addition, a large contingent of interstitial neurons can be classified as interneurons based on their neurochemical profile as well as on morphological criteria. WM- interneurons have multipolar or bipolar shapes and express GABA and a variety of other neuronal markers, such as calbindin and calretinin, the extracellular matrix protein reelin, or neuropeptide Y, somatostatin, and nitric oxide synthase. The heterogeneity of interstitial neurons may be relevant for the pathogenesis of Alzheimer disease and schizophrenia. Interstitial neurons are most prominent in human brain, and only rudimentary in the brain of non-primate mammals. These evolutionary differences have precluded adequate experimental work on this cell population, which is usually considered as a relict of the subplate, a transient compartment proper of development and without a known function in the adult brain. The primate-specific prominence of the subplate in late fetal stages points to an important role in the establishment of interstitial neurons. Neurons in the adult WM may be actively involved in coordinating inter-areal connectivity and regulation of blood flow. Further studies in primates will be needed to elucidate the developmental history, adult components and activities of this large neuronal system.
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