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Pilon F, Boisvert M, Potvin S. Losing the chain of thought: A meta-analysis of functional neuroimaging studies using verbal tasks in schizophrenia. J Psychiatr Res 2024; 169:238-246. [PMID: 38048673 DOI: 10.1016/j.jpsychires.2023.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 10/30/2023] [Accepted: 11/15/2023] [Indexed: 12/06/2023]
Abstract
BACKGROUND Disorganization symptoms are a main feature of schizophrenia, which include illogical and incoherent thinking, circumstantiality, tangentiality and loose associations. As these symptoms entail language deficits, several functional neuroimaging studies have been performed in schizophrenia using verbal tasks, producing somewhat heterogenous results. Hence, we performed a meta-analysis seeking to identify the most reliable neural alterations observed in schizophrenia patients during such tasks. METHODS Web of Sciences, PubMed, and EMBASE were searched for functional neuroimaging studies during verbal tasks (e.g. verbal fluency and semantic processing) in schizophrenia. Out of 795 screened articles, 33 were eligible for this meta-analysis. A coordinated-based meta-analysis was performed with the activation likelihood estimation (ALE) approach, using the cluster-level family-wise error (FWE) correction set at p < 0.05. RESULTS In schizophrenia, hyperactivations were observed in the left inferior frontal gyrus (IFG) and middle frontal gyrus (MFG) and hypoactivations were observed in the right IFG, the precentral gyrus and the left caudate nucleus. Another analysis pooling hyper- and hypoactivations revealed altered activations, firstly, in the left IFG and MFG, secondly, in the left precentral gyrus, IFG and insula, and, thirdly, in the left angular gyrus and precuneus. In the light of these results, not only classic language-related regions are abnormally activated during verbal tasks in schizophrenia, but also brain regions involved in executive functions, autobiographical memory and, unexpectedly, in motor functions. Further functional neuroimaging studies are needed to investigate the role of the striatum in linguistic sequencing in schizophrenia.
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Affiliation(s)
- Florence Pilon
- Centre de Recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montreal, Quebec, Canada; Department of Psychiatry and Addiction, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Mélanie Boisvert
- Centre de Recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montreal, Quebec, Canada; Department of Psychiatry and Addiction, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Stéphane Potvin
- Centre de Recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montreal, Quebec, Canada; Department of Psychiatry and Addiction, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada.
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Briggs RG, Pryor DP, Conner AK, Nix CE, Milton CK, Kuiper JK, Palejwala AH, Sughrue ME. The Artery of Aphasia, A Uniquely Sensitive Posterior Temporal Middle Cerebral Artery Branch that Supplies Language Areas in the Brain: Anatomy and Report of Four Cases. World Neurosurg 2019; 126:e65-e76. [PMID: 30735868 DOI: 10.1016/j.wneu.2019.01.159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Arterial disruption during brain surgery can cause devastating injuries to wide expanses of white and gray matter beyond the tumor resection cavity. Such damage may occur as a result of disrupting blood flow through en passage arteries. Identification of these arteries is critical to prevent unforeseen neurologic sequelae during brain tumor resection. In this study, we discuss one such artery, termed the artery of aphasia (AoA), which when disrupted can lead to receptive and expressive language deficits. METHODS We performed a retrospective review of all patients undergoing an awake craniotomy for resection of a glioma by the senior author from 2012 to 2018. Patients were included if they experienced language deficits secondary to postoperative infarction in the left posterior temporal lobe in the distribution of the AoA. The gross anatomy of the AoA was then compared with activation likelihood estimations of the auditory and semantic language networks using coordinate-based meta-analytic techniques. RESULTS We identified 4 patients with left-sided posterior temporal artery infarctions in the distribution of the AoA on diffusion-weighted magnetic resonance imaging. All 4 patients developed substantial expressive and receptive language deficits after surgery. Functional language improvement occurred in only 2/4 patients. Activation likelihood estimations localized parts of the auditory and semantic language networks in the distribution of the AoA. CONCLUSIONS The AoA is prone to blood flow disruption despite benign manipulation. Patients seem to have limited capacity for speech recovery after intraoperative ischemia in the distribution of this artery, which supplies parts of the auditory and semantic language networks.
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Affiliation(s)
- Robert G Briggs
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Dillon P Pryor
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Andrew K Conner
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Cameron E Nix
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Camille K Milton
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Joseph K Kuiper
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Ali H Palejwala
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Michael E Sughrue
- Department of Neurosurgery, Prince of Wales Private Hospital, Sydney, Australia.
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Tecelão D, Mendes A, Martins D, Fu C, Chaddock CA, Picchioni MM, McDonald C, Kalidindi S, Murray R, Prata DP. The effect of psychosis associated CACNA1C, and its epistasis with ZNF804A, on brain function. GENES BRAIN AND BEHAVIOR 2018; 18:e12510. [PMID: 30079586 DOI: 10.1111/gbb.12510] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 07/23/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022]
Abstract
CACNA1C-rs1006737 and ZNF804A-rs1344706 polymorphisms are among the most robustly associated with schizophrenia (SCZ) and bipolar disorder (BD), and recently with brain phenotypes. As these patients show abnormal verbal fluency (VF) and related brain activation, we asked whether the latter was affected by these polymorphisms (alone and in interaction)-to better understand how they might induce risk. We recently reported effects on functional VF-related (for ZNF804A-rs1344706) and structural (for both) connectivity. We genotyped and fMRI-scanned 54 SCZ, 40 BD and 80 controls during VF. With SPM, we assessed the main effect of CACNA1C-rs1006737, and its interaction with ZNF804A-rs1344706, and their interaction with diagnosis, on regional brain activation and functional connectivity (psychophysiological interactions-PPI). Using public data, we reported effects of CACNA1C-rs1006737 and diagnosis on brain expression. The CACNA1C-rs1006737 risk allele was associated with increased activation, particularly in the bilateral prefronto-temporal cortex and thalamus; decreased PPI, especially in the left temporal cortex; and gene expression in white matter and the cerebellum. We also found unprecedented evidence for epistasis (interaction between genetic polymorphisms) in the caudate nucleus, thalamus, and cingulate and temporal cortical activation; and CACNA1C up-regulation in SCZ and BD parietal cortices. Some effects were dependent on BD/SCZ diagnosis. All imaging results were whole-brain, voxel-wise, and familywise-error corrected. Our results support evidence implicating CACNA1C and ZNF804A in BD and SCZ, adding novel imaging evidence in clinical populations, and of epistasis-which needs further replication. Further scrutiny of the inherent neurobiological mechanisms may disclose their potential as putative drug targets.
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Affiliation(s)
- Diogo Tecelão
- Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Lisbon, Portugal
| | - Ana Mendes
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa
| | - Daniel Martins
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Cynthia Fu
- School of Psychology, The University of East London, London, UK
| | - Christopher A Chaddock
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Marco M Picchioni
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,St. Andrew's Academic Department, St Andrew's Healthcare, Northampton, UK
| | - Colm McDonald
- Centre for Neuroimaging and Cognitive Genomics (NICOG) & NCBES Galway Neuroscience Centre, College of Medicine, Nursing and Health Sciences, National University of Ireland Galway, Galway, Ireland
| | - Sridevi Kalidindi
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Robin Murray
- Department of Psychosis Studies, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Diana P Prata
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa.,Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,Instituto Universitário de Lisboa (ISCTE-IUL), Cis-IUL, Lisbon, Portugal
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Analysis of LINE-1 Elements in DNA from Postmortem Brains of Individuals with Schizophrenia. Neuropsychopharmacology 2017; 42:2602-2611. [PMID: 28585566 PMCID: PMC5686486 DOI: 10.1038/npp.2017.115] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/10/2017] [Accepted: 05/31/2017] [Indexed: 11/08/2022]
Abstract
Whereas some rare genetic variants convey high risk for schizophrenia (SZ), common alleles conveying even moderate risk remain elusive. Long interspersed element-1s (L1) are mobile retrotransposons comprising ~17% of the human genome. L1 retrotransposition can cause somatic mosaicism during neurodevelopment by insertional mutagenesis. We hypothesized that, compared to controls, patients diagnosed with schizophrenia (PDS) may have increased numbers of deleterious L1 insertions, perhaps occurring de novo, in brain-expressed genes of dorsolateral prefrontal cortex (DLPFC) neurons. Neuronal and non-neuronal nuclei were separated by fluorescence-activated cell sorting from postmortem DLPFC of 36 PDS and 26 age-matched controls. Genomic sequences flanking the 3'-side of L1s were amplified from neuronal DNA, and neuronal L1 libraries were sequenced. Aligned sequences were analyzed for L1 insertions using custom bioinformatics programs. Ontology and pathway analyses were done on lists of genes putatively disrupted by L1s in PDS and controls. Cellular or population allele frequencies of L1s were assessed by droplet digital PCR or Taqman genotyping. We observed a statistically significant increase in the proportion of intragenic novel L1s in DLPFC of PDS. We found over-representation of L1 insertions within the gene ontologies 'cell projection' and 'postsynaptic membrane' in the gene lists derived from PDS samples, but not from controls. Cellular allele frequencies of examined L1 insertions indicated heterozygosity in genomes of DLPFC cells. An L1 within ERI1 exoribonuclease family member 3 (ERI3) was found to associate with SZ. These results extend prior work documenting increased L1 genetic burden in the brains of PDS and also identify unique genes that may provide new insight into the pathophysiology of schizophrenia.
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Horwitz B. Identifying suicidal young adults. Nat Hum Behav 2017; 1:860-861. [PMID: 31024174 DOI: 10.1038/s41562-017-0239-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Barry Horwitz
- Chief of the Brain Imaging and Modeling Section at the National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, USA.
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Wu S, Wang H, Chen C, Zou J, Huang H, Li P, Zhao Y, Xu Q, Zhang L, Wang H, Pandit S, Dahal S, Chen J, Zhou Y, Jiang T, Wang G. Task Performance Modulates Functional Connectivity Involving the Dorsolateral Prefrontal Cortex in Patients with Schizophrenia. Front Psychol 2017; 8:56. [PMID: 28289394 PMCID: PMC5326798 DOI: 10.3389/fpsyg.2017.00056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 01/10/2017] [Indexed: 01/25/2023] Open
Abstract
Previous studies have suggested that patients with schizophrenia and healthy controls exhibit differential activation of and connectivity involving the dorsolateral prefrontal cortex (DLPFC) during working memory tasks, though their findings remain inconsistent. The functional integration perspective further suggests that working memory performance also modulates differences in functional interactions of the DLPFC between patients and controls. To explore this possibility, 45 healthy controls and 45 patients with schizophrenia were recruited to perform a 2-back task during functional magnetic resonance imaging (fMRI). Each group was further divided into two subgroups based on task performance to examine the modulatory effect of performance on functional interactions of the DLPFC, as measured via psychophysiological interaction (PPI) analyses. We observed that, in patients with schizophrenia who exhibited impaired working memory capacity and decreased brain activation/deactivation, functional interactions between the right/left DLPFC and angular cortex were decreased relative to those of healthy controls. Furthermore, we observed an interaction effect of working memory performance and diagnosis on functional connectivity between the right/left DLPFC seed region and posterior regions such as the angular cortex, fusiform gyrus, and middle occipital gyrus. This interaction effect was mainly driven by the negative correlation between functional connectivity and performance in healthy controls, and by the positive correlation in patients with schizophrenia. These results demonstrate the effects of inter-individual differences in working memory performance on functional interactions between the DLPFC and posterior regions in patients with schizophrenia as well as healthy controls, which may shed new light on the neural basis of working memory.
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Affiliation(s)
- Shihao Wu
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Huiling Wang
- Department of Psychiatry, Renmin Hospital of Wuhan UniversityWuhan, China; Hubei Provincial Key Laboratory of Developmentally Originated DiseaseWuhan, China
| | - Cheng Chen
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Jilin Zou
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Huan Huang
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Peifu Li
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Yilin Zhao
- Department of Radiology, Renmin Hospital of Wuhan University Wuhan, China
| | - Qizhong Xu
- Department of Radiology, Renmin Hospital of Wuhan University Wuhan, China
| | - Liang Zhang
- Department of Radiology, Renmin Hospital of Wuhan University Wuhan, China
| | - Hesheng Wang
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Sanjib Pandit
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Subodh Dahal
- Department of Psychiatry, Renmin Hospital of Wuhan University Wuhan, China
| | - Jun Chen
- Department of Radiology, Renmin Hospital of Wuhan University Wuhan, China
| | - Yuan Zhou
- CAS Key Laboratory of Behavioral Science, Institute of PsychologyBeijing, China; Department of Psychology, University of Chinese Academy of SciencesBeijing, China
| | - Tianzi Jiang
- Brainnetome Center, Institute of Automatuon, Chinese Academy of SciencesBeijing, China; Key Laboratory for NeuroInformation of the Ministry of Education, School of Life Science and Technology of ChinaChengdu, China
| | - Gaohua Wang
- Department of Psychiatry, Renmin Hospital of Wuhan UniversityWuhan, China; Hubei Institute of Neurology and Psychiatry ResearchWuhan, China; Hubei University of Science and TechnologyXianning, China
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Coupled neural systems underlie the production and comprehension of naturalistic narrative speech. Proc Natl Acad Sci U S A 2014; 111:E4687-96. [PMID: 25267658 DOI: 10.1073/pnas.1323812111] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Neuroimaging studies of language have typically focused on either production or comprehension of single speech utterances such as syllables, words, or sentences. In this study we used a new approach to functional MRI acquisition and analysis to characterize the neural responses during production and comprehension of complex real-life speech. First, using a time-warp based intrasubject correlation method, we identified all areas that are reliably activated in the brains of speakers telling a 15-min-long narrative. Next, we identified areas that are reliably activated in the brains of listeners as they comprehended that same narrative. This allowed us to identify networks of brain regions specific to production and comprehension, as well as those that are shared between the two processes. The results indicate that production of a real-life narrative is not localized to the left hemisphere but recruits an extensive bilateral network, which overlaps extensively with the comprehension system. Moreover, by directly comparing the neural activity time courses during production and comprehension of the same narrative we were able to identify not only the spatial overlap of activity but also areas in which the neural activity is coupled across the speaker's and listener's brains during production and comprehension of the same narrative. We demonstrate widespread bilateral coupling between production- and comprehension-related processing within both linguistic and nonlinguistic areas, exposing the surprising extent of shared processes across the two systems.
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Rao NP, Remington G. Targeting the dopamine receptor in schizophrenia: investigational drugs in Phase III trials. Expert Opin Pharmacother 2013; 15:373-83. [DOI: 10.1517/14656566.2014.873790] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Leroux E, Delcroix N, Alary M, Razafimandimby A, Brazo P, Delamillieure P, Dollfus S. Functional and white matter abnormalities in the language network in patients with schizophrenia: a combined study with diffusion tensor imaging and functional magnetic resonance imaging. Schizophr Res 2013; 150:93-100. [PMID: 23916391 DOI: 10.1016/j.schres.2013.07.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 06/14/2013] [Accepted: 07/05/2013] [Indexed: 01/14/2023]
Abstract
BACKGROUND Schizophrenia is a mental disorder characterized by functional abnormalities in the language network. Anatomical white matter (WM) abnormalities (volume and integrity) have also been reported for this pathology. Nevertheless, few studies have investigated anatomo-functional relationships in schizophrenia, and none has focused on the language comprehension network in relation to various diffusion parameters. We hypothesized that the WM abnormalities that are reflected by several diffusion parameters underlie functional deficits in the language network. METHODS Eighteen DSM-IV patients with schizophrenia and 18 healthy controls without any significant differences in sex, age, or level of education were included. First, functional brain activation within the language network was estimated. Then, using diffusion tensor imaging, fractional anisotropy (FA), radial diffusivity (RD), and mean diffusivity (MD) values were extracted within WM regions adjacent to this network and their anatomo-functional relationships were investigated. RESULTS Compared with healthy participants, both functional and diffusion deficits were observed in patients with schizophrenia. Primarily, an altered diffusion-functional relationship was observed in patients in the left middle temporal region: functional activations were positively correlated with FA, but were negatively correlated with RD. CONCLUSIONS Our findings indicate a close relationship between diffusion and functional deficits in patients with schizophrenia, suggesting that WM integrity disturbance might be one cause of functional alterations in the language network in patients with schizophrenia. Thus, the present multimodal study improves our understanding of the pathophysiology of schizophrenia.
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Affiliation(s)
- Elise Leroux
- CHU de Caen, Service de Psychiatrie, Centre Esquirol, Caen, F-14000, France; CNRS, UMR 6301 ISTCT, ISTS team, GIP CYCERON, Bd Henri Becquerel, BP5229, F-14074 Caen cedex, France.
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Rao NP, Remington G. Investigational drugs for schizophrenia targeting the dopamine receptor: Phase II trials. Expert Opin Investig Drugs 2013; 22:881-94. [DOI: 10.1517/13543784.2013.795945] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Liakakis G, Nickel J, Seitz R. Diversity of the inferior frontal gyrus—A meta-analysis of neuroimaging studies. Behav Brain Res 2011; 225:341-7. [DOI: 10.1016/j.bbr.2011.06.022] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 06/16/2011] [Accepted: 06/18/2011] [Indexed: 11/16/2022]
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Smee C, Krabbendam L, O'Daly O, Prins AM, Nalesnik N, Morley L, Samson G, Shergill S. An fMRI study of prefrontal dysfunction and symptomatic recovery in schizophrenia. Acta Psychiatr Scand 2011; 123:440-50. [PMID: 21083650 DOI: 10.1111/j.1600-0447.2010.01632.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Prefrontal cortical dysfunction has been implicated in the pathophysiology of schizophrenia but it is unclear to what extent these are related to changes in symptomatology as well as task demand. METHOD We examined the neural correlates of symptom change and task demand during a longitudinal functional magnetic resonance imaging (fMRI) study using a verbal fluency task with differential task demands in patients with schizophrenia and matched healthy control subjects. The fMRI data were acquired using clustered acquisition technique, enabling ongoing monitoring of behavioural responses, in the patient group on two occasions separated by 6-8 weeks, and the control group at baseline. RESULTS Positive psychotic symptoms were significantly reduced over the 6-8-week duration of the study. This change was associated with increased activation within the left middle frontal gyrus and decreased activation of the left precuneus. An interaction between symptom change and task demand was evident in the activation of the left middle frontal gyrus. The decrease in positive symptoms was associated with normalisation of activation in the dorsolateral prefrontal cortex and a decrease in parietal activation during the verbal fluency task. CONCLUSION The data supports the role of dysfunctional prefronto-parietal relationships in the genesis of positive psychotic symptoms.
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Affiliation(s)
- C Smee
- Psychological Medicine, King's College London Institute of Psychiatry, UK
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Daumann J, Wagner D, Heekeren K, Neukirch A, Thiel CM, Gouzoulis-Mayfrank E. Neuronal correlates of visual and auditory alertness in the DMT and ketamine model of psychosis. J Psychopharmacol 2010; 24:1515-24. [PMID: 19304859 DOI: 10.1177/0269881109103227] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Deficits in attentional functions belong to the core cognitive symptoms in schizophrenic patients. Alertness is a nonselective attention component that refers to a state of general readiness that improves stimulus processing and response initiation. The main goal of the present study was to investigate cerebral correlates of alertness in the human 5HT(2A) agonist and N-methyl-D-aspartic acid (NMDA) antagonist model of psychosis. Fourteen healthy volunteers participated in a randomized double-blind, cross-over event-related functional magnetic resonance imaging (fMRI) study with dimethyltryptamine (DMT) and S-ketamine. A target detection task with cued and uncued trials in both the visual and the auditory modality was used. Administration of DMT led to decreased blood oxygenation level-dependent response during performance of an alertness task, particularly in extrastriate regions during visual alerting and in temporal regions during auditory alerting. In general, the effects for the visual modality were more pronounced. In contrast, administration of S-ketamine led to increased cortical activation in the left insula and precentral gyrus in the auditory modality. The results of the present study might deliver more insight into potential differences and overlapping pathomechanisms in schizophrenia. These conclusions must remain preliminary and should be explored by further fMRI studies with schizophrenic patients performing modality-specific alertness tasks.
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Affiliation(s)
- J Daumann
- Department of Psychiatry and Psychotherapy, University of Cologne, Germany.
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Nagels A, Kirner-Veselinovic A, Krach S, Kircher T. Neural correlates of S-ketamine induced psychosis during overt continuous verbal fluency. Neuroimage 2010; 54:1307-14. [PMID: 20727411 DOI: 10.1016/j.neuroimage.2010.08.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 08/09/2010] [Accepted: 08/10/2010] [Indexed: 10/19/2022] Open
Abstract
The glutamatergic N-methyl-D-aspartate (NMDA) receptor has been implicated in the pathophysiology of schizophrenia. Administered to healthy volunteers, a subanesthetic dose of the non-competitive NMDA receptor antagonist ketamine leads to psychopathological symptoms similar to those observed in schizophrenia. In patients with schizophrenia, ketamine exacerbates the core symptoms of illness, supporting the hypothesis of a glutamatergic dysfunction. In a counterbalanced, placebo-controlled, double-blind study design, healthy subjects were administered a continuous subanesthetic S-ketamine infusion while differences in BOLD responses measured with fMRI were detected. During the scanning period, subjects performed continuous overt verbal fluency tasks (phonological, lexical and semantic). Ketamine-induced psychopathological symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Ketamine elicited psychosis like psychopathology. Post-hoc t-tests revealed significant differences between placebo and ketamine for the amounts of words generated during lexical and semantic verbal fluency, while the phonological domain remained unaffected. Ketamine led to enhanced cortical activations in supramarginal and frontal brain regions for phonological and lexical verbal fluency, but not for semantic verbal fluency. Ketamine induces activation changes in healthy subjects similar to those observed in patients with schizophrenia, particularly in frontal and temporal brain regions. Our results provide further support for the hypothesis of an NMDA receptor dysfunction in the pathophysiology of schizophrenia.
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Affiliation(s)
- Arne Nagels
- Department of Psychiatry and Psychotherapy, Philipps-University Marburg, Marburg, Germany.
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Abstract
After decades of research aimed at elucidating the pathophysiology and etiology of schizophrenia, it has become increasingly apparent that it is an illness knowing few boundaries. Psychopathological manifestations extend across several domains, impacting multiple facets of real-world functioning for the affected individual. Even within one such domain, arguably the most enduring, difficult to treat, and devastating to long-term functioning-executive impairment-there are not only a host of disrupted component processes, but also a complex underlying dysfunctional neural architecture. Further, just as implicated brain structures (eg, dorsolateral prefrontal cortex) through postmortem and neuroimaging techniques continue to show alterations in multiple, interacting signaling pathways, so too does evolving understanding of genetic risk factors suggest multiple molecular entry points to illness liability. With this expansive network of interactions in mind, the present chapter takes a systems-level approach to executive dysfunction in schizophrenia, by identifying key regions both within and outside of the frontal lobes that show changes in schizophrenia and are important in cognitive control neural circuitry, summarizing current knowledge of their relevant functional interactions, and reviewing emerging links between schizophrenia risk genetics and characteristic executive circuit aberrancies observed with neuroimaging methods.
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Ikezawa K, Iwase M, Ishii R, Azechi M, Canuet L, Ohi K, Yasuda Y, Iike N, Kurimoto R, Takahashi H, Nakahachi T, Sekiyama R, Yoshida T, Kazui H, Hashimoto R, Takeda M. Impaired regional hemodynamic response in schizophrenia during multiple prefrontal activation tasks: a two-channel near-infrared spectroscopy study. Schizophr Res 2009; 108:93-103. [PMID: 19157786 DOI: 10.1016/j.schres.2008.12.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 12/01/2008] [Accepted: 12/04/2008] [Indexed: 10/21/2022]
Abstract
In schizophrenia, dysfunction of the prefrontal cortex (PFC), regarded as a core feature of the disease, has been investigated by different neuroimaging methods. Near infrared spectroscopy (NIRS), a novel neurophysiological method, is being increasingly used in the investigation of frontal dysfunction in schizophrenia. However, NIRS measurements during multiple frontal activation tasks have been rarely reported. The purpose of this study was to compare hemodynamic changes in the PFC between patients with schizophrenia and healthy controls during four different types of frontal lobe tasks using a 2-channel NIRS system. Thirty patients with schizophrenia and thirty age- and gender-matched healthy controls were enrolled in this study. In both groups, changes in oxygenated hemoglobin concentration (Delta[oxyHb]) at the bilateral forehead were measured during Verbal fluency test letter version (VFT-letter), VFT category version, Tower of Hanoi (TOH), the Sternberg and Stroop tasks. Regarding Delta[oxyHb] in PFC, a diagnosis group effect was found for VFT-letter and TOH. Significant negative correlation was found between left Delta[oxyHb] during TOH and negative and cognitive symptom scores in schizophrenia patients. Right Delta[oxyHb] during TOH also showed significant negative correlation with cognitive symptoms scores. No significant correlation between Delta[oxyHb] and clinical characteristics were observed during VFT-letter. These findings suggest that among a battery of frontal lobe tasks administered to schizophrenia patients, VFT-letter and TOH are more sensitive to detect PFC activation, as indicated by Delta[oxyHb] using a 2-channel NIRS. Taken together, these findings and those of previous neuroimaging studies suggest that VFT-letter and TOH might represent possible candidate physiological markers of prefrontal dysfunction in schizophrenia, though extensive testing in clinical settings will be necessary.
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Affiliation(s)
- Koji Ikezawa
- Department of Psychiatry, Osaka University Graduate School of Medicine, D3, 2-2 Yamadaoka, Suita, Osaka, 565-0871 Japan.
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17
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Wynn JK, Green MF, Engel S, Korb A, Lee J, Glahn D, Nuechterlein KH, Cohen MS. Increased extent of object-selective cortex in schizophrenia. Psychiatry Res 2008; 164:97-105. [PMID: 18938066 PMCID: PMC2683746 DOI: 10.1016/j.pscychresns.2008.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 11/26/2007] [Accepted: 01/08/2008] [Indexed: 11/28/2022]
Abstract
Schizophrenia patients exhibit deficits in various stages of visual information processing. Despite recent informative efforts to examine visual processing in schizophrenia with functional magnetic resonance imaging (fMRI), much remains unknown about the basic function, structure, and organization of key early visual processing areas in schizophrenia. This study examined magnitude and topography of regional brain activity in three early visual processing areas: early retinotopically organized areas (V1-V4), motion-sensitive areas (human area MT, hMT+), and object-recognition areas (lateral occipital complex, LO). Using visual stimuli that are known to preferentially activate each respective region, we compared responses in these areas in 22 schizophrenia patients and 19 normal controls. Activity in all three regions was of similar amplitude in schizophrenia patients and normal controls. Activity in retinotopically organized areas and hMT+ showed good spatial overlap between groups. However, activation of LO was more widely distributed in patients compared with normal controls. The findings of abnormal spatial organization of LO in schizophrenia patients may converge with behavioral evidence of deficits in schizophrenia patients for object-recognition tasks that are believed to be mediated by LO activity.
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Affiliation(s)
- Jonathan K. Wynn
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles; Los Angeles, CA, USA,VA Greater Los Angeles Healthcare System; Los Angeles, CA, USA,Corresponding Author: Jonathan K. Wynn, Ph.D., VA Greater Los Angeles Healthcare System, MIRECC, Bldg. 210, 11301 Wilshire Blvd., Los Angeles, CA 90073, USA, Phone: (310) 478-3711 x44957, Fax: (310) 268-4056,
| | - Michael F. Green
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles; Los Angeles, CA, USA,VA Greater Los Angeles Healthcare System; Los Angeles, CA, USA
| | - Stephen Engel
- Department of Psychology, University of California, Los Angeles; Los Angeles, CA, USA
| | - Alex Korb
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles; Los Angeles, CA, USA
| | - Junghee Lee
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles; Los Angeles, CA, USA,VA Greater Los Angeles Healthcare System; Los Angeles, CA, USA
| | - David Glahn
- Department of Psychiatry, The University of Texas Health Science Center at San Antonio; San Antonio, TX, USA
| | - Keith H. Nuechterlein
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles; Los Angeles, CA, USA,Department of Psychology, University of California, Los Angeles; Los Angeles, CA, USA
| | - Mark S. Cohen
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles; Los Angeles, CA, USA,Department of Psychology, University of California, Los Angeles; Los Angeles, CA, USA
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18
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Andreasen NC, Calage CA, O'Leary DS, O'Leary DS. Theory of mind and schizophrenia: a positron emission tomography study of medication-free patients. Schizophr Bull 2008; 34:708-19. [PMID: 18559406 PMCID: PMC2632446 DOI: 10.1093/schbul/sbn034] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND "Theory of mind" (TOM) refers to the ability to attribute mental states (ie, beliefs and goals) to one's self and others and to recognize that behaviors are guided by these mental states. This capacity, critical for social competence, is impaired in schizophrenia. We undertook a study of TOM in a group of patients with schizophrenia and healthy controls. METHOD We used positron emission tomography to identify the neural circuits recruited during a verbal task that required participants to attribute mental states to a character in a story of their creation. The comparison task consisted of reading aloud a neutral story, controlling for the speech component of the task. RESULTS Patients and controls generated the same percentage of TOM utterances. However, the two groups had markedly different patterns of brain activation. Compared with controls, patients had a lower blood flow in multiple regions in the left hemisphere including the frontal and visual association cortices, posterior hippocampus, and insula. The flow was also lower in contralateral areas in the lateral cerebellum and vermis, thalamus, and posterior insula. On the other hand, the flow was higher in the patients predominantly in the right hemisphere, including multiple frontal and parietal regions, insula, visual association cortex, and pulvinar. DISCUSSION The areas of lower flow are consistent with previous studies indicating impairment in recruiting cortical-cerebellar circuitry in schizophrenia. The areas of higher flow may reflect a need to draw on the right hemisphere to compensate for deficits in left hemisphere networks that include frontal cortex, anterior cingulate, cerebellum, and thalamus.
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Affiliation(s)
- Nancy C. Andreasen
- Andrew H. Woods Chair of Psychiatry,To whom correspondence should be addressed; Department of Psychiatry, The University of Iowa Carver College of Medicine, 200 Hawkins Drive, Room W278GH, Iowa City, IA 52242-1057; tel: 319-356-1553, fax: 319-353-8300, e-mail:
| | - Chadi A. Calage
- Department of Psychiatry, The University of Iowa Carver College of Medicine, Iowa City, IA 52242-1057
| | - Daniel S. O'Leary
- Department of Psychiatry, The University of Iowa Carver College of Medicine, Iowa City, IA 52242-1057
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19
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Dollfus S, Razafimandimby A, Maiza O, Lebain P, Brazo P, Beaucousin V, Lecardeur L, Delamillieure P, Mazoyer B, Tzourio-Mazoyer N. Functional deficit in the medial prefrontal cortex during a language comprehension task in patients with schizophrenia. Schizophr Res 2008; 99:304-11. [PMID: 18178386 DOI: 10.1016/j.schres.2007.11.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 10/30/2007] [Accepted: 11/02/2007] [Indexed: 11/15/2022]
Abstract
OBJECTIVE We and others have observed that patients with schizophrenia commonly presented a reduced left recruitment in language semantic brain regions. However, most studies include patients with leftward and rightward lateralizations for language. We investigated whether a cohort comprised purely of patients with typical lateralization (leftward) presented a reduced left recruitment in semantic regions during a language comprehension task. The goal was to reduce the inter-subject variability and thus improve the resolution for studying functional abnormalities in the language network. METHODS Twenty-three patients with schizophrenia (DSM-IV) were matched with healthy subjects in age, sex, level of education and handedness. All patients exhibited leftward lateralization for language. Functional MRI was performed as subjects listened to a story comprising characters and social interactions. Functional MRI signal variations were analyzed individually and compared among groups. RESULTS Although no differences were observed in the recruitment of the semantic language network, patients with schizophrenia presented significantly lower signal variations compared to controls in the medial part of the left superior frontal gyrus (MF1) (x=-6, y=58, z=20; Z(score)=5.6; p<0.001 uncorrected). This region corresponded to the Theory of Mind (ToM) network. Only 5 of the 23 patients (21.7%) and 21 of the 23 (91.3%) control subjects demonstrated a positive signal variation in this area. CONCLUSIONS A left functional deficit was observed in a core region of the ToM network in patients with schizophrenia and typical lateralizations for language. This functional defect could represent a neural basis for impaired social interaction and communication in patients with schizophrenia.
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Affiliation(s)
- Sonia Dollfus
- Groupe d'Imagerie Neurofonctionnelle, UMR 6194 CNRS/CEA/Université de Caen, Université Paris 5, Centre Cyceron, Bl H. Becquerel, Caen, 14000, France.
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20
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Tan HY, Callicott JH, Weinberger DR. Dysfunctional and compensatory prefrontal cortical systems, genes and the pathogenesis of schizophrenia. Cereb Cortex 2007; 17 Suppl 1:i171-81. [PMID: 17726000 DOI: 10.1093/cercor/bhm069] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cognitive deficits are critical determinants of schizophrenia morbidity. In this review, we offer a mechanistic perspective regarding schizophrenia-related changes observed in prefrontal cortical networks engaged in working memory. A body of earlier work converges on aberrations in putative macrocircuit stability and functional efficiency as the underlying pathophysiology of the cognitive deficits in schizophrenia. In parsing the dysfunctional prefrontal cortical dynamics of schizophrenia, recent functional magnetic resonance imaging and electoencephalography works suggest that in the context of reduced capacity for executive aspects of working memory, patients engage a larger network of cortical regions consistent with an interplay between reduced signal-to-noise components and the recruitment of compensatory networks. The genetic programming underlying these systems-level cortical interactions has been examined under the lens of certain schizophrenia susceptibility genes, especially catechol-o-methyltransferase (COMT) and GRM3. Variation in COMT, which presumably impacts on cortical dopamine signaling, translates into variable neural strategies for working memory and altering patterns of intracortical functional correlations. GRM3, which impacts on synaptic glutamate, interacts with COMT and exaggerates the genetic dissection of cortical processing strategies. These findings reveal novel insights into the modulation and parcellation of working memory processing in cortical assemblies and provide a mechanistic link between susceptibility genes and cortical pathophysiology related to schizophrenia.
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Affiliation(s)
- Hao-Yang Tan
- Genes, Cognition and Psychosis Program, Clinical Brain Disorders Branch, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
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21
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Ehlis AC, Herrmann MJ, Plichta MM, Fallgatter AJ. Cortical activation during two verbal fluency tasks in schizophrenic patients and healthy controls as assessed by multi-channel near-infrared spectroscopy. Psychiatry Res 2007; 156:1-13. [PMID: 17587553 DOI: 10.1016/j.pscychresns.2006.11.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 07/10/2006] [Accepted: 11/25/2006] [Indexed: 11/20/2022]
Abstract
Near-infrared spectroscopy (NIRS) is an optical imaging method that allows non-invasive in-vivo measurements of changes in the concentration of oxygenated (O(2)Hb) and deoxygenated (HHb) hemoglobin in brain tissue. For the present study, we examined 12 schizophrenic patients and 12 age- and gender-matched healthy controls by means of multi-channel NIRS (Optical Topography; ETG-100, Hitachi Medical Co., Japan) during performance of two versions of the Verbal Fluency Test (VFT; letter and category version). The results indicate that the verbal fluency tasks generally led to clear frontal activation in healthy controls, which was significantly reduced in schizophrenic patients. The letter version of the VFT induced overall stronger activation than the category version, the group difference being particularly pronounced for phonological fluency. Moreover, significant positive correlations between task-related activation effects in prefrontal and temporal NIRS channels were found in both schizophrenic patients and healthy controls. The results confirm functional deficits within the frontal lobe in patients suffering from schizophrenic illnesses, but do not confirm previous findings on abnormal fronto-temporal correlations or increased temporal activation in this group of patients. The data furthermore underline the usefulness of functional NIRS in monitoring hemodynamic responses associated with cognitive processes in healthy controls and patients with neuro-psychiatric disorders.
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Affiliation(s)
- Ann-Christine Ehlis
- Laboratory for Psychophysiology and Functional Imaging, Department of Psychiatry and Psychotherapy, University Hospital Wüerzburg, Füechsleinstrasse 15, 97080 Wüerzburg, Germany.
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22
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Palomo T, Kostrzewa RM, Beninger RJ, Archer T. Treatment consideration and manifest complexity in comorbid neuropsychiatric disorders. Neurotox Res 2007; 12:43-60. [PMID: 17513199 DOI: 10.1007/bf03033900] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Psychiatric disorders may co-occur in the same individual. These include, for example, substance abuse or obsessive-compulsive disorder with schizophrenia, and movement disorders or epilepsy with affective dysfunctional states. Medications may produce iatrogenic effects, for example cognitive impairments that co-occur with the residual symptoms of the primary disorder being treated. The observation of comorbid disorders in some cases may reflect diagnostic overlap. Impulsivity, impulsiveness or impulsive behaviour is implicated in a range of diagnostic conditions including substance abuse, affective disorder and obsessive-compulsive disorder. These observations suggest a need to re-evaluate established diagnostic criteria and disorder definitions, focusing instead on symptoms and symptom-profiles.
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Affiliation(s)
- Tomas Palomo
- Psychiatry Service, 12 de Octubre, University Hospital, Madrid 28041, Spain
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23
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Apud JA, Weinberger DR. Treatment of cognitive deficits associated with schizophrenia: potential role of catechol-O-methyltransferase inhibitors. CNS Drugs 2007; 21:535-57. [PMID: 17579498 DOI: 10.2165/00023210-200721070-00002] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In the last two decades, understanding of the dynamics of dopamine function in the prefrontal cortex and its role in prefrontal cortex physiology has opened up new avenues for therapeutic interventions in conditions in which prefrontal cortex function is compromised. Neuropsychological and imaging studies of prefrontal information processing have confirmed specific cognitive and neurophysiological abnormalities in individuals with schizophrenia. Because such findings are also observed in the healthy siblings of patients with schizophrenia, they may represent intermediate phenotypes related to schizophrenia susceptibility genes.Catechol-O-methyltransferase (COMT) represents an important candidate as a susceptibility gene for cognitive dysfunction in schizophrenia because of the unique role this enzyme plays in regulating prefrontal dopaminergic function. A functional COMT polymorphism (Val158Met) predicts performance in tasks of prefrontal executive function and the neurophysiological response measured with electroencephalography and functional magnetic resonance imaging in tasks assessing working memory. In fact, individuals with the Val/Val genotype, which encodes for the high-activity enzyme resulting in lower dopamine concentrations in the prefrontal cortex, perform less well and are less efficient physiologically than Met/Met individuals. These findings raise the possibility of new pharmacological interventions for the treatment of prefrontal cortex dysfunction and of predicting outcome based on COMT genotype. One strategy consists of the use of CNS-penetrant COMT inhibitors such as tolcapone. A second strategy is to increase extracellular dopamine concentrations in the frontal cortex by blocking the noradrenaline (norepinephrine) reuptake system, a secondary mechanism responsible for the disposal of dopamine from synaptic clefts in the prefrontal cortex. A third possibility involves the use of modafinil, a drug with an unclear mechanism of action but with positive effects on working memory in rodents. The potential of these drugs to improve executive cognitive function by selectively increasing dopamine load in the frontal cortex but not in subcortical territories, and the possibility that response to them may be modified by a COMT polymorphism, provides a novel genotype-based targeted pharmacological approach without abuse potential for the treatment of cognitive disorder in schizophrenia and in other conditions involving prefrontal cortex dysfunction.
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Affiliation(s)
- José A Apud
- Clinical Brain Disorders Branch, Genes, Cognition and Psychosis Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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24
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Schneider F, Habel U, Reske M, Kellermann T, Stöcker T, Shah NJ, Zilles K, Braus DF, Schmitt A, Schlösser R, Wagner M, Frommann I, Kircher T, Rapp A, Meisenzahl E, Ufer S, Ruhrmann S, Thienel R, Sauer H, Henn FA, Gaebel W. Neural correlates of working memory dysfunction in first-episode schizophrenia patients: an fMRI multi-center study. Schizophr Res 2007; 89:198-210. [PMID: 17010573 DOI: 10.1016/j.schres.2006.07.021] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 07/16/2006] [Accepted: 07/23/2006] [Indexed: 11/17/2022]
Abstract
Working memory dysfunction is a prominent impairment in patients with schizophrenia. Our aim was to determine cerebral dysfunctions by means of functional magnetic resonance imaging (fMRI) in a large sample of first-episode schizophrenia patients during a working memory task. 75 first-episode schizophrenia patients and 81 control subjects, recruited within a multi-center study, performed 2- and 0-back tasks while brain activation was measured with fMRI. In order to guarantee comparability between data quality from different scanners, we developed and adopted a standardized, fully automated quality assurance of scanner hard- and software as well as a measure for in vivo data quality. After these quality-control measures had been implemented, 48 patients and 57 controls were included in the final analysis. During attention-related processes, even when the performance between patients and controls was comparable, there was a recognizable emergence of cerebral dysfunctions with hypoactivations in the ventrolateral prefrontal cortex (VLPFC), in the superior temporal cortex and in the thalamus. During working memory performance, parietal hypoactivations, especially in the precuneus, were prominent and were accompanied by poorer performance in patients. A hyperfrontality emerged in the ventrolateral prefrontal cortex. Hence, results point to a dysfunctional ventrolateral prefrontal-parietal network during working memory in patients, suggesting impairments in basic functions such as retrieval, storage and maintenance. The brain activation pattern of this large and significant sample of first-episode schizophrenia patients indicates an imbalanced system failing to adjust the amount of brain activity required in the cerebral network involved in attention and working memory.
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Affiliation(s)
- Frank Schneider
- Department of Psychiatry and Psychotherapy, RWTH Aachen University, Pauwelsstr. 30, 52074 Aachen, Germany.
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25
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Brown GG, Eyler LT. Methodological and Conceptual Issues in Functional Magnetic Resonance Imaging: Applications to Schizophrenia Research. Annu Rev Clin Psychol 2006; 2:51-81. [PMID: 17716064 DOI: 10.1146/annurev.clinpsy.2.022305.095241] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Functional magnetic resonance imaging (MRI) is a noninvasive, highly repeatable, and increasingly available method to study disordered brain activity among patients with psychological or neurological disorders. In this chapter the biophysical principles underlying functional MRI are presented, and methodological limitations of the method are discussed. Artifacts related to the biophysical basis of the functional MRI signal or associated with image acquisition methods are presented, as are artifacts related to baseline effects-especially those associated with medication, caffeine, and nicotine use. The difficulties associated with the comparison of groups of subjects differing in performance receive special attention. The limitations of cognitive subtraction designs for functional MRI are also discussed. Functional MRI studies of schizophrenia patients are used to illustrate these points.
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Affiliation(s)
- Gregory G Brown
- Psychology Service, Veterans Administration San Diego Healthcare System, and Psychiatry Department, University of California, San Diego, California 92161, USA.
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26
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Abstract
OBJECTIVES There is evidence for differential neural alterations within the prefrontal cortex (PFC) in bipolar disorder I (BDI) and schizophrenia that may translate into different cognitive deficits. Our objective was to compare the cognitive profile of stable BDI and schizophrenic patients using neuropsychological tasks which utilize frontal systems but differ in terms of the exact neural circuits and cognitive processes involved. METHODS We studied 43 patients with BDI, 54 with schizophrenia and 46 matched healthy participants. All participants completed (i) the Wisconsin Card Sorting Test (WCST) which is known to recruit the dorsal and ventral PFC, (ii) the verbal fluency task (VFT), which engages frontal-temporal regions, and (iii) the Stroop Colour Word Test (SWCT) which depends on the integrity of the cingulo-frontal network. A series of multivariate analyses examined differences between the cognitive profiles of BD and schizophrenic patients relative to that of healthy participants controlling for general intellectual ability and gender. RESULTS Bipolar disorder I patients showed minimal verbal fluency impairment while schizophrenic patients demonstrated marked deficits on this task relative to the control and BDI groups. The two patient groups had comparable performance on the WCST. In the SWCT, schizophrenic patients showed impairment in both congruent and incongruent conditions while BD patients had deficits only in the latter. CONCLUSIONS Absence of significant verbal fluency abnormalities and by inference dysfunction in the associated fronto-temporal circuitry may distinguish BDI from schizophrenia. Both disorders may show impairment in tasks involving cingulo-frontal networks with evidence of greater cingulate dysfunction in schizophrenia.
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Affiliation(s)
- S Frangou
- Section of Neurobiology of Psychosis, Institute of Psychiatry, King's Coillege London, London, UK.
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27
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Sommer IEC, Oranje B, Ramsey NF, Klerk FA, Mandl RCW, Westenberg HGM, Kahn RS. The influence of amphetamine on language activation: an fMRI study. Psychopharmacology (Berl) 2006; 183:387-93. [PMID: 16284750 DOI: 10.1007/s00213-005-0176-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Accepted: 09/13/2004] [Indexed: 10/25/2022]
Abstract
RATIONALE Amphetamine administration has been found to affect the degree of cerebral dominance for motor control in animals. In humans, cerebral dopamine neurotransmission is also correlated to motor dominance. Since language dominance is related to motor dominance, amphetamine might also affect cerebral dominance for language. METHODS To test this hypothesis, language activation was measured twice with functional magnetic resonance imaging in ten healthy right-handed men in a double-blind crossover design 2 h after amphetamine or placebo administration. RESULTS Language-related activation increased significantly in task-related areas, but the individual lateralization index was not affected in the amphetamine condition as compared to placebo. CONCLUSIONS This finding suggests that short-termed alterations in the dopaminergic neurotransmission do not affect language dominance.
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Affiliation(s)
- Iris E C Sommer
- Rudolf Magnus Institute of Neuroscience Psychiatry Department, University Medical Center Utrecht, Heidelberglaan 100, 3584CX, Utrecht, The Netherlands.
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28
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Fu CHY, Abel KM, Allin MPG, Gasston D, Costafreda SG, Suckling J, Williams SCR, McGuire PK. Effects of ketamine on prefrontal and striatal regions in an overt verbal fluency task: a functional magnetic resonance imaging study. Psychopharmacology (Berl) 2005; 183:92-102. [PMID: 16228196 DOI: 10.1007/s00213-005-0154-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Accepted: 06/23/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Glutamatergic dysfunction at N-methyl-D: -aspartate (NMDA) receptors has been proposed as a neurochemical model for schizophrenia. A key feature of this disorder is impairments in cognitive function. OBJECTIVE The present study sought to investigate the effects of ketamine, an NMDA antagonist, on the performance and neural correlates of verbal fluency, a task that engages executive function. METHODS Ten healthy dextral male volunteers received intravenous placebo normal saline or ketamine (bolus of 0.23 mg/kg and infusion of 0.65 mg/kg), administered in a double-blind, randomized order, during two functional magnetic resonance imaging sessions. During scanning, subjects performed a verbal fluency task. Two levels of cognitive load were examined in the task, and overt responses were acquired in order to measure subject performance on-line. RESULTS Ketamine induced symptoms in the healthy individuals comparable to an acute psychotic state. Although ketamine did not significantly impair task performance relative to placebo, an interaction of task demand with ketamine was observed in the anterior cingulate, prefrontal, and striatal regions. CONCLUSIONS The behavioural and functional effects of ketamine during verbal fluency in healthy individuals were comparable to those evident in patients with schizophrenia. The findings support a role for glutamatergic dysfunction in the pathophysiology of schizophrenia.
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Affiliation(s)
- Cynthia H Y Fu
- Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK.
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29
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Kubota Y, Toichi M, Shimizu M, Mason RA, Coconcea CM, Findling RL, Yamamoto K, Calabrese JR. Prefrontal activation during verbal fluency tests in schizophrenia--a near-infrared spectroscopy (NIRS) study. Schizophr Res 2005; 77:65-73. [PMID: 16005386 DOI: 10.1016/j.schres.2005.01.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2004] [Revised: 01/16/2005] [Accepted: 01/17/2005] [Indexed: 10/25/2022]
Abstract
Letter- or semantically-cued verbal fluency tests (VFT) induce different, but overlapping activities in the prefrontal cortex (PFC) in healthy subjects. Functional differences between letter and semantic VFT may be important in elucidating the nature of language-related problems in schizophrenia since more profound impairment in semantically-cued retrieval may be suggestive of semantic system dysfunction specific to this disorder. However, the functional differences between the letter vs. semantic VFT on prefrontal metabolism in the subjects with schizophrenia have not been described. In the present study, we used near-infrared spectroscopy (NIRS) to assess hemoglobin concentration changes in the bilateral PFCs in subjects and controls. Sixteen subjects with schizophrenia and 19 healthy controls performed letter and semantic VFTs. Prefrontal hemodynamic changes were simultaneously monitored by NIRS. While healthy subjects performed both tasks equivalently, the subjects with schizophrenia showed more compromised performance in the semantic VFTs compared to the letter VFTs. NIRS measurement revealed that the pattern of PFC activation was greater during the letter VFT when compared to the semantic VFT in the healthy subjects, suggesting more prominent PFC involvement in letter-cued retrieval. In contrast, the subjects with schizophrenia showed the opposite pattern of activation, implying that the semantic mode of lexical access might impose greater cognitive demands on the PFC. The present study is the first to detect abnormal patterns of PFC activation in adults with schizophrenia in response to the distinct cognitive demands associated with letter and semantic VFT.
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Affiliation(s)
- Yasutaka Kubota
- Mood Disorders Program, Department of Psychiatry, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH, USA.
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Risterucci C, Jeanneau K, Schöppenthau S, Bielser T, Künnecke B, von Kienlin M, Moreau JL. Functional magnetic resonance imaging reveals similar brain activity changes in two different animal models of schizophrenia. Psychopharmacology (Berl) 2005; 180:724-34. [PMID: 15726331 DOI: 10.1007/s00213-005-2204-8] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Accepted: 02/06/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE AND OBJECTIVES In schizophrenia research, most of the functional imaging studies have been performed in psychotic patients, but little is known about brain areas involved in the expression of psychotic-like symptoms in animal models. The objective of this study was to visualize and compare brain activity abnormalities in a neurodevelopmental and a pharmacological animal model of schizophrenia. METHODS Blood perfusion of specific brain areas, taken as indirect measure of brain activity, was investigated in adult rats following either neonatal ventral hippocampal lesion or acute administration of phencyclidine. Quantitative perfusion magnetic resonance imaging was performed on five frontal brain slices using the continuous arterial spin labeling technique. The mean perfusion was calculated in several brain structures, which were identified on anatomical images. RESULTS Lesioned animals exhibiting deficits in prepulse inhibition of the startle reflex showed a significant blood perfusion increase in the nucleus accumbens, basolateral amygdala, ventral pallidum, entorhinal-piriform cortex, orbital prefrontal cortex, and in the bed nucleus of the stria terminalis, and a decrease of perfusion in the temporal cortex. Similar effects were seen following acute phencyclidine administration in naïve animals. CONCLUSION Our data point out specific cortical and subcortical brain areas involved in the development of psychotic-like symptoms in two different animal models of schizophrenia. The observed brain activity abnormalities are reminiscent of classical neuroimaging findings described in schizophrenic patients.
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Affiliation(s)
- Céline Risterucci
- CNS Research, F. Hoffmann-La Roche Ltd., PRBD-N, Bldg 72/129, 4070, Basel, Switzerland.
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Thermenos HW, Goldstein JM, Buka SL, Poldrack RA, Koch JK, Tsuang MT, Seidman LJ. The effect of working memory performance on functional MRI in schizophrenia. Schizophr Res 2005; 74:179-94. [PMID: 15721998 DOI: 10.1016/j.schres.2004.07.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2004] [Revised: 07/16/2004] [Accepted: 07/23/2004] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Studies of prefrontal cortical (PFC) function in schizophrenia have been inconsistent, with studies showing both increased and decreased PFC activation compared to healthy controls. Discrepant findings may be due to task performance effects or demographic differences between samples. We report functional magnetic resonance imaging (fMRI) data comparing subjects with schizophrenia and healthy controls performing a 2-back working memory (WM) task, addressing the effects of task performance. METHODS Twenty-two controls and 14 patients with DSM-IV schizophrenia, scanned on a Siemens 1.5 T scanner, performed a visual letter 2-back task and control task (CPT-X) during fMRI. Data were analyzed using Statistical Parametric Mapping (SPM)-99. RESULTS After statistical adjustment for performance differences, persons with schizophrenia showed significantly greater activation than controls in the right medial frontal gyrus and left inferior parietal lobule/medial temporal gyrus region (BA 39/40), and a trend toward greater activation in the left ventrolateral PFC. This pattern was also observed in demographically matched subgroups of participants. CONCLUSIONS Data are consistent with findings reported in recent studies showing increased PFC and parietal activation in schizophrenia when the effects of reduced WM task performance in patients with schizophrenia are addressed. Further studies are needed to clarify the pathophysiological basis of WM load sensitivity in schizophrenia and its relationship to genes.
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Affiliation(s)
- Heidi W Thermenos
- Harvard Medical School, Department of Psychiatry, Massachusetts Mental Health Center, Boston, MA 02115, USA.
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Molina V, Sanz J, Sarramea F, Benito C, Palomo T. Prefrontal atrophy in first episodes of schizophrenia associated with limbic metabolic hyperactivity. J Psychiatr Res 2005; 39:117-27. [PMID: 15589559 DOI: 10.1016/j.jpsychires.2004.06.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Revised: 05/03/2004] [Accepted: 06/09/2004] [Indexed: 01/09/2023]
Abstract
Reduced volume and activity of the prefrontal (PF) cortical gray matter (GM) and hippocampal hypermetabolism are repeated findings in schizophrenia. There is still an information deficit about the significance of reduction of PF GM in schizophrenia, and a simultaneous study of PF anatomy and activity and limbic metabolism can contribute to fill that deficit. In order to do so, we used positron emission tomography (PET) with 18-fluoro-deoxy-glucose (FDG) during an attention task and magnetic resonance imaging (MRI) to study a sample of first episodes of psychosis. We included 21 first episodes (FE) of psychosis and 16 healthy controls. A diagnosis of schizophrenia was confirmed in the follow-up in eleven of these patients and ruled out in the remaining 10 cases. Volumes of PF GM were determined and also activity in the same region and in the hippocampus. Residual GM was estimated in the PF region as a quantitative measurement of the degree of atrophy in each individual, using age and intracranial volume data from a set of 45 healthy controls and linear regression. Patients with schizophrenia had lower PF metabolic activation and greater hippocampal activity than controls. FE patients without schizophrenia were no different in any parameter as compared to controls. Patients with schizophrenia presented an inverse and significant association between GM deficit and hippocampal activity that was not observed in controls or in patients without schizophrenia. The same association was previously described by our group using PET in the resting state in recent-onset and chronic patients with schizophrenia. These findings support a loss in PF inhibitory capacity as a possible link between anatomical and functional alterations in schizophrenia.
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Affiliation(s)
- Vicente Molina
- Department of Psychiatry, Hospital Clínico Universitario, Paseo de San Vicente, 58-182, E-37007 Salamanca, Spain.
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Ragland JD, Gur RC, Valdez J, Turetsky BI, Elliott M, Kohler C, Siegel S, Kanes S, Gur RE. Event-related fMRI of frontotemporal activity during word encoding and recognition in schizophrenia. Am J Psychiatry 2004; 161:1004-15. [PMID: 15169688 PMCID: PMC4332807 DOI: 10.1176/appi.ajp.161.6.1004] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Neuropsychological studies have demonstrated verbal episodic memory deficits in schizophrenia during word encoding and retrieval. This study examined neural substrates of memory in an analysis that controlled for successful retrieval. METHOD Event-related blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to measure brain activation during word encoding and recognition in 14 patients with schizophrenia and 15 healthy comparison subjects. An unbiased multiple linear regression procedure was used to model the BOLD response, and task effects were detected by contrasting the signal before and after stimulus onset. RESULTS Patients attended during encoding and had unimpaired reaction times and normal response biases during recognition, but they had lower recognition discriminability scores, compared with the healthy subjects. Analysis of contrasts was restricted to correct items. Previous findings of a deficit in bilateral prefrontal cortex activation during encoding in patients were reproduced, but patients showed greater parahippocampal activation rather than deficits in temporal lobe activation. During recognition, left dorsolateral prefrontal cortex activation was lower in the patients and right anterior prefrontal cortex activation was preserved, as in the authors' previous study using positron emission tomography. Successful retrieval was associated with greater right dorsolateral prefrontal cortex activation in the comparison subjects, whereas orbitofrontal, superior frontal, mesial temporal, middle temporal, and inferior parietal regions were more active in the patients during successful retrieval. CONCLUSIONS The pattern of prefrontal cortex underactivation and parahippocampal overactivation in the patients suggests that functional connectivity of dorsolateral prefrontal and temporal-limbic structures is disrupted by schizophrenia. This disruption may be reflected in the memory strategies of patients with schizophrenia, which include reliance on rote rehearsal rather than associative semantic processing.
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Affiliation(s)
- J Daniel Ragland
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Thermenos HW, Seidman LJ, Breiter H, Goldstein JM, Goodman JM, Poldrack R, Faraone SV, Tsuang MT. Functional magnetic resonance imaging during auditory verbal working memory in nonpsychotic relatives of persons with schizophrenia: a pilot study. Biol Psychiatry 2004; 55:490-500. [PMID: 15023577 DOI: 10.1016/j.biopsych.2003.11.014] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Revised: 11/18/2003] [Accepted: 11/20/2003] [Indexed: 11/26/2022]
Abstract
BACKGROUND First-degree relatives of persons with schizophrenia carry elevated genetic risk for the illness and show deficits on high-load information processing tasks. We used functional magnetic resonance imaging (fMRI) to test whether nonpsychotic relatives show altered functional activation in the prefrontal cortex (PFC), thalamus, hippocampus, and anterior cingulate during a working memory task requiring interference resolution. METHODS Twelve nonpsychotic relatives of persons with schizophrenia and 12 healthy control subjects were administered an auditory, verbal working memory version of the Continuous Performance Test during fMRI. An asymmetric, spin-echo, T2*-weighted sequence (15 contiguous, 7-mm axial slices) was acquired on a full-body MR scanner. Data were analyzed by Statistical Parametric Mapping (SPM). RESULTS Compared with control subjects, relatives showed greater task-elicited activation in the PFC and the anterior and dorsomedial thalamus. When task performance was controlled, relatives showed significantly greater activation in the anterior cingulate. When effects of other potentially confounding variables were controlled, relatives generally showed significantly greater activation in the dorsomedial thalamus and anterior cingulate. CONCLUSIONS This pilot study suggests that relatives of persons with schizophrenia have subtle differences in brain function in the absence of psychosis. These differences add to the growing literature identifying neurobiological vulnerabilities to schizophrenia.
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Affiliation(s)
- Heidi W Thermenos
- Department of Psychology and Brain Research Institute (RP), University of California, Los Angeles, Los Angeles, California, USA
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Kubicki M, McCarley RW, Nestor PG, Huh T, Kikinis R, Shenton ME, Wible CG. An fMRI study of semantic processing in men with schizophrenia. Neuroimage 2004; 20:1923-33. [PMID: 14683698 PMCID: PMC2806220 DOI: 10.1016/s1053-8119(03)00383-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
As a means toward understanding the neural bases of schizophrenic thought disturbance, we examined brain activation patterns in response to semantically and superficially encoded words in patients with schizophrenia. Nine male schizophrenic and 9 male control subjects were tested in a visual levels of processing (LOP) task first outside the magnet and then during the fMRI scanning procedures (using a different set of words). During the experiments visual words were presented under two conditions. Under the deep, semantic encoding condition, subjects made semantic judgments as to whether the words were abstract or concrete. Under the shallow, nonsemantic encoding condition, subjects made perceptual judgments of the font size (uppercase/lowercase) of the presented words. After performance of the behavioral task, a recognition test was used to assess the depth of processing effect, defined as better performance for semantically encoded words than for perceptually encoded words. For the scanned version only, the words for both conditions were repeated in order to assess repetition-priming effects. Reaction times were assessed in both testing scenarios. Both groups showed the expected depth of processing effect for recognition, and control subjects showed the expected increased activation of the left inferior prefrontal cortex (LIPC) under semantic encoding relative to perceptual encoding conditions as well as repetition priming for semantic conditions only. In contrast, schizophrenics showed similar patterns of fMRI activation regardless of condition. Most striking in relation to controls, patients showed decreased LIFC activation concurrent with increased left superior temporal gyrus activation for semantic encoding versus shallow encoding. Furthermore, schizophrenia subjects did not show the repetition priming effect, either behaviorally or as a decrease in LIPC activity. In patients with schizophrenia, LIFC underactivation and left superior temporal gyrus overactivation for semantically encoded words may reflect a disease-related disruption of a distributed frontal temporal network that is engaged in the representation and processing of meaning of words, text, and discourse and which may underlie schizophrenic thought disturbance.
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Affiliation(s)
- M Kubicki
- Clinical Neuroscience Division, Laboratory of Neuroscience, Boston VA Healthcare System-Brockton Division, Department of Psychiatry, Harvard Medical School, Brockton, MA 02301, USA.
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Sommer IEC, Ramsey NF, Mandl RCW, van Oel CJ, Kahn RS. Language activation in monozygotic twins discordant for schizophrenia. Br J Psychiatry 2004; 184:128-35. [PMID: 14754824 DOI: 10.1192/bjp.184.2.128] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND In previous functional magnetic resonance imaging (fMRI) studies, participants with schizophrenia showed decreased language lateralisation, resulting from increased activation of the right hemisphere compared with controls. AIM To determine whether decreased lateralisation and increased right cerebral language activation constitute genetic predispositions for schizophrenia. METHOD Language activation was measured using fMRI in 12 right-handed monozygotic twin pairs discordant for schizophrenia and 12 healthy right-handed monozygotic twin pairs who were twin pairs who were matched for gender, age and education. RESULTS Language lateralisation was decreased in discordant twin pairs compared with the healthy twin pairs. The groups did not differ in activation of the language-related areas of the left hemisphere, but language-related activation in the right hemisphere was activation in the significantly higher in the discordant twin pairs than in the healthy pairs. Within the discordant twin pairs, language lateralisation was not significantly different between patients with schizophrenia and their co-twins. CONCLUSIONS Decreased language lateralisation may constitute a genetic predisposition for schizophrenia.
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Affiliation(s)
- Iris E C Sommer
- Rudolf Magnus Institute of Neuroscience Psychiatry Department, University Medical Center, Utrecht, The Netherlands.
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Shinba T, Nagano M, Kariya N, Ogawa K, Shinozaki T, Shimosato S, Hoshi Y. Near-infrared spectroscopy analysis of frontal lobe dysfunction in schizophrenia. Biol Psychiatry 2004; 55:154-64. [PMID: 14732595 DOI: 10.1016/s0006-3223(03)00547-x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Previous studies have shown that near-infrared spectroscopy (NIRS) has high temporal resolution, requires little restraint, and is suitable for examining the effect of psychological tasks on brain circulation. In the present study, frontal function in schizophrenic patients was analyzed by NIRS during random number generation (RNG), ruler-catching (RC), and sequential finger-to-thumb (SFT) tasks. METHODS Two sets of NIRS probes were attached to the foreheads of 13 schizophrenic patients and 10 control subjects approximately at Fp1-F7 and Fp2-F8. Near-infrared spectroscopy was conducted at a sampling rate of 1 Hz, with the pathlength being determined by time-resolved spectroscopy with differential pathlength factor measurements. The absolute changes in oxygenated (oxy-Hb) and deoxygenated (deoxy-Hb) hemoglobin concentrations in response to each task were measured, and total hemoglobin (total-Hb) concentration was calculated as the sum of the two. RESULTS During RNG task, total- and oxy-Hb concentrations increased, and deoxy-Hb decreased, but the responses were significantly smaller in schizophrenic patients. During RC task, oxy-Hb in schizophrenic patients tended to decrease, in contrast to the mostly increasing response in control subjects. No group difference was observed during SFT task. CONCLUSIONS Task-dependent profile of functional abnormalities was observed in schizophrenic frontal brain metabolism. These results support the usefulness of NIRS data in investigating frontal lobe dysfunction and evaluating psychopathologic condition in schizophrenic patients.
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Affiliation(s)
- Toshikazu Shinba
- Department of Stress Disorders Research and Integrative Neuroscience, Tokyo Institute of Psychiatry, Tokyo, Japan
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Sharma T. Insights and treatment options for psychiatric disorders guided by functional MRI. J Clin Invest 2003; 112:10-8. [PMID: 12840052 PMCID: PMC162300 DOI: 10.1172/jci19166] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Tonmoy Sharma
- Clinical Neuroscience Research Center, Kent, United Kingdom.
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Abstract
Schizophrenia is a highly heritable, neurobehavioral disorder; however, the mode of inheritance is complex, and linkage findings have been difficult to replicate. Some consistent linkage findings have emerged on chromosomes 1, 6, 8, 11, 13, 15, and 22. New methods are being developed for candidate gene identification, including the use of neurobiologic phenotypes observed in relatives of persons with schizophrenia. Neuroimaging studies of relatives implicate abnormal hippocampal structure and inefficient prefrontal network functioning, probably representing mild variants of the abnormalities observed in schizophrenia. These characteristics may represent stable markers of vulnerability to schizophrenia, because they are not confounded by effects of antipsychotic drugs or psychosis. Recent studies provide evidence for a small role of the catechol-O-methyltransferase gene on 22q, and the serotonin receptor transporter gene on 17q11-q12 in the development of schizophrenia. Linking genes and brain regions or networks is an important step in identification of the pathophysiology of schizophrenia.
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MESH Headings
- Brain/abnormalities
- Brain/physiopathology
- Brain-Derived Neurotrophic Factor/genetics
- Carrier Proteins/genetics
- Catechol O-Methyltransferase/genetics
- Chromosomes, Human, Pair 1/genetics
- Chromosomes, Human, Pair 11/genetics
- Chromosomes, Human, Pair 13/genetics
- Chromosomes, Human, Pair 15/genetics
- Chromosomes, Human, Pair 17/genetics
- Chromosomes, Human, Pair 22/genetics
- Chromosomes, Human, Pair 6/genetics
- Chromosomes, Human, Pair 8/genetics
- Hippocampus/abnormalities
- Hippocampus/physiopathology
- Humans
- Membrane Glycoproteins/genetics
- Membrane Transport Proteins
- Nerve Tissue Proteins
- Prefrontal Cortex/abnormalities
- Prefrontal Cortex/physiopathology
- Schizophrenia/genetics
- Schizophrenia/physiopathology
- Serotonin Plasma Membrane Transport Proteins
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Affiliation(s)
- Larry J Seidman
- Neuropsychology Laboratory, Massachusetts Mental Health Center, 74 Fenwood Road, Boston, MA 02115, USA.
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Jeannerod M. [Problems in recognizing the self: a neuropsychological approach to the positive symptoms of schizophrenia]. Med Sci (Paris) 2003; 19:621-4. [PMID: 12836397 DOI: 10.1051/medsci/2003195621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This article present a review of recent work on cognitive neuroscience approaches of schizophrenia. Some of the symptoms displayed by schizophrenic patients can be reconsidered within the framework of disorganization of well identified cognitive functions, like self-recognition. Neuroimaging techniques can reveal in these patients disruption of neural networks normally involved in such functions.
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Affiliation(s)
- Marc Jeannerod
- Cnrs UMR 5015, Institut des Sciences Cognitives, 67, boulevard Pinel, 69675 Bron, France.
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Weiss EM, Golaszewski S, Mottaghy FM, Hofer A, Hausmann A, Kemmler G, Kremser C, Brinkhoff C, Felber SR, Fleischhacker WW. Brain activation patterns during a selective attention test-a functional MRI study in healthy volunteers and patients with schizophrenia. Psychiatry Res 2003; 123:1-15. [PMID: 12738340 DOI: 10.1016/s0925-4927(03)00019-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Functional magnetic resonance imaging was used to compare cortical activation patterns in healthy volunteers with those in patients with schizophrenia during a modified verbal Stroop task. Healthy subjects (n=13) and patients with schizophrenia (n=13) on stable antipsychotic treatment, matched on demographic variables, were included. Patients were preselected on the basis of good performance on a selective attention test. Patients with schizophrenia showed a significantly increased pattern of activation in the left and right inferior frontal cortex and the anterior cingulate cortex. A significant negative correlation between activation of the left prefrontal cortex and accuracy in the modified Stroop test was observed for healthy controls but not schizophrenia patients. Although both groups recruited the prefrontal cortex during the modified Stroop task, for the schizophrenia patients this activation was bilateral, whereas for the controls this activation was primarily in the left hemisphere, suggesting that patients with schizophrenia recruited more prefrontal regions to perform the task with the same accuracy as healthy controls. Our findings of increased activity across multiple areas of the brain, including dorsolateral frontal cortex and anterior cingulate, in patients with schizophrenia who perform relatively well on a task of selective attention give further evidence that task performance may be a confounding factor in the interpretation of neuroimaging results.
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Affiliation(s)
- Elisabeth M Weiss
- Department of Biological Psychiatry, Innsbruck University Clinics, Anichstrasse 35, A-6020 Innsbruck, Austria.
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Winterer G, Weinberger DR. Cortical signal-to-noise ratio: insight into the pathophysiology and genetics of schizophrenia. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1566-2772(03)00019-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Fresquet N, Yamamoto J, Sandner G. Frontal lesions do not alter the differential extinction of taste aversion conditioning in rats, when using two methods of sucrose delivery. Behav Brain Res 2003; 141:25-34. [PMID: 12672556 DOI: 10.1016/s0166-4328(02)00317-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The frontal cortex is involved in the planning of behavioural responses and in the processing of their outcomes. Thus it contributes to several learning mechanisms, including those of conditioned taste aversion (CTA). A solution of sucrose drunk freely by a rat from a drinking tube-self-drinking protocol (SD)-was used as a conditioned stimulus in CTA. The intake of this solution was followed by gastric malaise. It produced an aversion to sucrose that withstood extinction over a week of repetitive tests. But, when the sucrose was perfused intra-orally (IO), i.e. not depending on any specific action by the rat, the extinction of aversion was much faster. Several factors may explain this differential extinction including the contribution of contextual factors linked to the achievement of an action and/or the enhancement of the attention towards the outcome of the action (the taste). The processing of such factors is usually believed to require the prefrontal cortex or the cingulate cortex (CgC). In our first experiment, the frontal cortex was totally transected. In the second experiment, the CgC was removed by aspiration. None of these lesions elicited any change in CTA, either in IO or in SD conditions, meaning that the differential extinction remained. The surprising absence of a frontal lesion effect was thought to indicate the low attentional demand required in both CTA protocols.
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Affiliation(s)
- Nadine Fresquet
- U 405 INSERM, Faculty of Medicine, Department of Physiology, University Louis Pasteur, 11 Rue Humann, 67085 Strasbourg, France
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Sommer IEC, Ramsey NF, Mandl RCW, Kahn RS. Language lateralization in female patients with schizophrenia: an fMRI study. Schizophr Res 2003; 60:183-90. [PMID: 12591582 DOI: 10.1016/s0920-9964(02)00300-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Gender differences in schizophrenia are among the most consistently reported findings in schizophrenia research. However, the biological substrate underlying these gender differences is still largely unknown. Differences in language lateralization between men and women may underlie some gender differences in schizophrenia. In previous functional imaging studies, language lateralization was found to be decreased in male schizophrenia patients as compared to healthy males, which was due to enhanced language activation of the right hemisphere as compared to the healthy males. It could be hypothesized that decreased language lateralization in schizophrenia is gender specific, i.e. decreased lateralization in male patients and normal lateralization in female patients. To test this hypothesis, language activation was measured in 12 right-handed female patients with schizophrenia and 12 healthy females, and compared to findings in 12 male patients and 12 male controls of an earlier study. Language lateralization was significantly lower in the female patients (0.44) as compared to the female controls (0.75), which was due to increased activation of the right-sided language areas (patients: 19 voxels; controls: 8 voxels), while left hemisphere activation was similar in patients and controls. When these data are compared to the male patients and controls, both patient groups had lower lateralization than their healthy counterparts, but there was no difference between male and female patients. In both sexes, decreased lateralization resulted from increased right hemispheric language activation, which suggests a failure to inhibit nondominant language areas in schizophrenia. These findings indicate that lower language lateralization in women is not likely to underlie gender differences in schizophrenia.
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Affiliation(s)
- I E C Sommer
- Department of Neuroscience, University Medical Center Utrecht, Heidelberglaan 100, 3584CX, Utrecht, The Netherlands.
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Paulus MP, Frank L, Brown GG, Braff DL. Schizophrenia subjects show intact success-related neural activation but impaired uncertainty processing during decision-making. Neuropsychopharmacology 2003; 28:795-806. [PMID: 12655327 DOI: 10.1038/sj.npp.1300108] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Decision-making is a complex process that is important for everyday life. This study examined the effect of the degree of success, and outcome uncertainty, on decision-making and associated neural substrate activation in schizophrenia subjects (SZS) and normal comparison subjects (NCS). A total of 15 subjects with a diagnosis of schizophrenia and 15 age- and education-matched NCS participated in this study. These subjects completed the two-choice prediction task during functional magnetic resonance imaging. Decision-making characteristics and activation of neural substrates were obtained at 20, 50, or 80% error rate. Success and uncertainty influenced the behavioral characteristics on the two-choice prediction task, and the task-related activation in SZS and NCS. Neither success nor uncertainty differentially affected the behavioral characteristics of SZS relative to NCS during the two-choice prediction task. Nonetheless, there was a significant interaction between group and error rate in bilateral parietal cortex. The activation in NCS was the highest when the outcome was most uncertain. In contrast, task-related activation in SZS was not modulated by the degree of uncertainty. Thus, SZS failed to utilize the parietal cortex to process decision-making situations with highly uncertain outcomes.
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Affiliation(s)
- Martin P Paulus
- Laboratory of Biological Dynamics and Theoretical Medicine, University of California at San Diego, La Jolla, CA, USA.
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Quintana J, Wong T, Ortiz-Portillo E, Kovalik E, Davidson T, Marder SR, Mazziotta JC. Prefrontal-posterior parietal networks in schizophrenia: primary dysfunctions and secondary compensations. Biol Psychiatry 2003; 53:12-24. [PMID: 12513941 DOI: 10.1016/s0006-3223(02)01435-x] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Working memory (WM) deficits are well known in schizophrenia and have been associated with abnormal activation patterns of the prefrontal cortex (PFC) during cognitive performance. The magnitude and particularly the direction of the PFC activation -- i.e., increased (hyperfrontality) or decreased (hypofrontality) -- in schizophrenia, as well as its pathophysiological implications, remain controversial. Working memory is supported by a distributed neural network, whose main components are the PFC and the posterior parietal (PPC) cortices. Monkey studies indicate that, during WM performance, PFC functional lesions may be compensated by the PPC if task demands center mainly on anticipating responses, but not if they center on remembering cues. We hypothesized that a primarily dysfunctional PFC in schizophrenia might show hypofrontality or hyperfrontality as a result, respectively, of efficient or inefficient PPC compensation, as dictated by task demands. To test our proposition, we biased the demands of WM tasks toward anticipating responses or remembering cues and measured its impact on the PFC-PPC functional balance in a group of schizophrenic patients and one of normal control subjects. METHODS We used functional magnetic resonance imaging to measure correlates of neuronal activity in the PFC and PPC of schizophrenic patients and control subjects performing WM tasks that either demanded information retention or allowed for response anticipation. RESULTS When compared to control subjects, schizophrenic patients exhibited decreased PFC activation and increased PPC activation during anticipatory WM performance, and increased PFC activation during mnemonic WM performance. CONCLUSIONS In schizophrenia, a PFC dysfunction results in hypo- or hyperfrontality as a function of whether other alternate areas of a PFC-PPC network for WM are available and efficacious in supporting specific task demands.
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Affiliation(s)
- Javier Quintana
- West Los Angeles Department of Veterans Affairs Health Care Center and Department of Psychiatry, University of California at Los Angeles, School of Medicine, USA
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Matsui M, Yoneyama E, Sumiyoshi T, Noguchi K, Nohara S, Suzuki M, Kawasaki Y, Seto H, Kurachi M. Lack of self-control as assessed by a personality inventory is related to reduced volume of supplementary motor area. Psychiatry Res 2002; 116:53-61. [PMID: 12426034 DOI: 10.1016/s0925-4927(02)00070-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study was performed to examine the relationship between schizophrenia-related personality and brain morphometry. Magnetic resonance (MR) imaging and schizophrenia-related personality scales extracted from the Minnesota Multiphasic Personality Inventory (MMPI) were administered to 42 university students. Analysis of the relationships between the gray matter segmented from the MR images on a voxel-by-voxel basis through the use of the statistical parametric mapping technique and the schizophrenia-related personality subscale scores from the MMPI revealed that lack of self-control subscale scores were negatively related to the gray matter volume of the supplementary motor area (SMA). Furthermore, it was suggested that self-control including self-inhibition is associated with the density of the SMA, the precuneous and the cerebellar vermis, which govern voluntary movements and motor imagery. These results provide important clues to the neural basis for the disturbance of self commonly observed in schizophrenia spectrum disorders.
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Affiliation(s)
- Mié Matsui
- Department of Psychology, School of Medicine, Toyama Medical and Pharmaceutical University, Toyama, Japan.
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48
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Welchew DE, Honey GD, Sharma T, Robbins TW, Bullmore ET. Multidimensional scaling of integrated neurocognitive function and schizophrenia as a disconnexion disorder. Neuroimage 2002; 17:1227-39. [PMID: 12414263 DOI: 10.1006/nimg.2002.1246] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Multidimensional scaling (MDS) is a multivariate statistical technique that can be used to define subsystems of functionally connected brain regions based on the analysis of functional magnetic resonance imaging (fMRI) data. Here we introduce three-way multidimensional scaling as a method for the analysis of a group of fMRI data, which yields both a generic interregional configuration in low-dimensional space and a measure of each individual's deviation from the generic configuration. The distance between two generic interregional configurations obtained by MDS of two groups of data can be minimized by generalized Procrustes analysis, and the probability under the null hypothesis (that the two groups are sampled from the same population) of any residual group difference in interregional configurations can be assessed by a permutation test. These methods are developed and applied to activated fMRI time series acquired from 19 patients with schizophrenia and 20 normal comparison subjects during the performance of a semantic categorization and subvocal rehearsal task. The first three scaling dimensions are interpretable in terms of the major anatomical or functional subsystems of the activated system: "left-right," "input processing-other," and "subvocal output-other". We found no significant global or local differences between groups in interregional configurations in this 3D space. However, there was significantly greater variability of interregional configurations within the group of patients with schizophrenia. The implications for schizophrenia as a disconnexion disorder are discussed.
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Affiliation(s)
- D E Welchew
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
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49
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Audenaert K, Goethals I, Van Laere K, Lahorte P, Brans B, Versijpt J, Vervaet M, Beelaert L, Van Heeringen K, Dierckx R. SPECT neuropsychological activation procedure with the Verbal Fluency Test in attempted suicide patients. Nucl Med Commun 2002; 23:907-16. [PMID: 12195096 DOI: 10.1097/00006231-200209000-00015] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Performance on the Verbal Fluency Test, as a measure of the ability of initiating processes, is reduced in depressed suicidal patients. The hampered results in this prefrontal executive task parallel the reduction in prefrontal blood perfusion and metabolism in depressed subjects. A neuropsychological activation study with the verbal fluency paradigm could evaluate a possible blunted increase in perfusion in the prefrontal cortex in depressed suicidal patients. Twenty clinically depressed patients who had recently attempted suicide and 20 healthy volunteers were included in a single photon emission computed tomography (SPECT) split-dose activation study following a verbal fluency paradigm. Statistical parametric mapping was used to determine voxelwise significant changes. Differences in regional cortical activation between the letter fluency and category fluency tasks in attempted suicide patients were found. These patients showed a blunted increase in perfusion in the prefrontal cortex. Methodological restrictions concerning group uniformity, medication bias and subjective effort of the participants are discussed. Our findings indicate a blunted increase in prefrontal blood perfusion as a possible biological reason for reduced drive and loss of initiative in attempted suicide patients.
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Affiliation(s)
- Kurt Audenaert
- Department of Nuclear Medicine, Ghent University Hospital, Ghent University, 185 De Pintelaan, B-9000 Ghent, Belgium.
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50
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Wykes T, Brammer M, Mellers J, Bray P, Reeder C, Williams C, Corner J. Effects on the brain of a psychological treatment: cognitive remediation therapy: functional magnetic resonance imaging in schizophrenia. Br J Psychiatry 2002; 181:144-52. [PMID: 12151286 DOI: 10.1017/s0007125000161872] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The results of one randomised control trial testing a psychological rehabilitation programme aimed at information processing strategies showed improvements in cognition post-treatment. AIMS To determine whether there are concomitant brain activation changes as a result of engaging in cognitive remediation therapy (CRT). METHOD Three groups (patients receiving control therapy or CRT and a healthy control group) were investigated in a repeated measures design using the two-back test. Functional magnetic resonance imaging (fMRI) data and a broad assessment of executive functioning were completed at baseline and post-treatment. Brain activation changes were identified after accounting for possible task-correlated motion artefact. RESULTS fMRI analyses indicate that the control group showed decreased activation but the two patient groups showed an increase in activation over time. The patient group that received successful CRT had significantly increased brain activation in regions associated with working memory, particularly the frontocortical areas. CONCLUSIONS This is the first time that brain activation changes in a seriously disabled group of patients with schizophrenia can be associated clearly with psychological rather than pharmacological therapy.
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Affiliation(s)
- Til Wykes
- Department of Psychiatry, Institute of Psychiatry, London, UK.
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