2 Ak Malhotra, D. Goldman, N. Ozaki, et al., Lack of association between polymorphisms in the 5HT2 receptor gene and the antipsychotic response to clozapine, Am J Psychiatry ((in press)). ... Visit SciVerse ScienceDirect to see if you... more
2 Ak Malhotra, D. Goldman, N. Ozaki, et al., Lack of association between polymorphisms in the 5HT2 receptor gene and the antipsychotic response to clozapine, Am J Psychiatry ((in press)). ... Visit SciVerse ScienceDirect to see if you have access via your institution.
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Research Interests: Computer Science, Neuroimaging, Magnetic Resonance Imaging, Functional MRI, Medicine, and 15 moreAutobiographical Memory, Hippocampus, Humans, Emergency Room, Female, Neuroimage, Male, Aged, Middle Aged, Oxygen, Adult, Control Group, Functional Laterality, Functional brain imaging, and Medical and Health Sciences
This paper reviews recent empirical findings related to prefrontal and executive function in unipolar depression. While a number of reviews have dealt with either the neuropsychological literature or findings from imaging studies, the... more
This paper reviews recent empirical findings related to prefrontal and executive function in unipolar depression. While a number of reviews have dealt with either the neuropsychological literature or findings from imaging studies, the present review addresses both, as well as findings from studies that have combined brain-imaging techniques with neuropsychological measures. This combined approach is of great interest as the performance of a structured task may act to load the areas of interest and reduce variance, thus making the imaging evidence more valuable; while the use of imaging provides a check that the neuropsychological tasks are indeed engaging the structures whose performance they are intended to assess. Prominent models of the neurobiology of depression implicate involvement of the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC). The evidence from combined imaging and neuropsychological studies supports the involvement of the ACC, but is less clear in the case of the DLPFC. However, the limited number of such studies conducted to date means that conclusions must be tentative and further studies employing this combined approach may be of great value.
Research Interests: Neuroscience, Cognitive Science, Neuropsychology, Brain Imaging, Prefrontal Cortex, and 11 moreExecutive Function, Humans, Animals, Depressive Disorder, Diagnostic Imaging, Neurosciences, Area of Interest, Cognition disorders, Anterior cingulate cortex, Dorsolateral Prefrontal Cortex, and Neuropsychological Tests
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Abstract: Monitoring one’s thoughts (in the verbal modality) is thought to be critically dependent on the interaction between areas that generate and perceive inner speech in the frontal and temporal cortex,... more
Abstract: Monitoring one’s thoughts (in the verbal modality) is thought to be critically dependent on the interaction between areas that generate and perceive inner speech in the frontal and temporal cortex, respectively.Weusedfunctionalmagneticresonanceimaging(fMRI)toexaminetherelationshipbetween activity in these areas while the rate of inner speech generation was varied experimentally. The faster rate wasassociatedwithactivationintheleftinferiorfrontalgyrus,therightpre-andpostcentralgyriandboth superiortemporalgyri.Thus,temporalcorticalactivationwasassociatedwithincreasingtherateofcovert articulation, in the absence of external auditory input, suggesting that there is effective fronto-temporal connectivity. Furthermore, this may provide support for the existence of feed forward models, which suggest that activity in regions responsible for verbal perception is modulated by activity in areas that
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Research Interests: Genetics, Human Genetics, Polymorphism, Complementary and Alternative Medicine, Family history, and 15 moreDNA, Dopamine, Humans, Female, Male, Polymerase Chain Reaction, Middle Aged, Genotype, Adult, Genetic Association, Allele Frequency, Age of Onset, alleles, Gene frequency, and Paediatrics and reproductive medicine
OBJECTIVE Small Japanese studies have suggested that patients with schizophrenia have higher rates of the HLA-DR1 gene than normal subjects. The authors' goal in the present study was to confirm this finding in a larger number of... more
OBJECTIVE Small Japanese studies have suggested that patients with schizophrenia have higher rates of the HLA-DR1 gene than normal subjects. The authors' goal in the present study was to confirm this finding in a larger number of Japanese subjects. They also investigated the rate of DR4 in Japanese patients with schizophrenia because it has been reported that Caucasian patients with schizophrenia have higher rates of DR4. METHOD They studied the occurrence of the HLA-DRB1 gene in 233 unrelated Japanese patients with schizophrenia compared with the occurrence of the gene in a group of 493 healthy Japanese volunteers. RESULTS A larger proportion of the patients with schizophrenia (15.9%) than the comparison subjects (10.5%) were found to have DR1 (DRB1*0101). The proportion of patients (36.9%) and comparison subjects (40.6%) with DR4 did not differ significantly. CONCLUSIONS Consistent with the findings of three other Japanese studies, the findings of the present study suggest tha...
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Research Interests: Magnetic Resonance Imaging, Adolescent, Medicine, Brain development, Humans, and 15 moreCorpus Callosum, Hallucinations, Male, Asymmetry, Dichotic Listening, Agenesis of the Corpus Callosum, Adult, Degeneration, Auditory verbal hallucinations, Brain Structure, Functional Laterality, Magnetic resonance image, Dichotic Listening tests, Medical and Health Sciences, and Macho
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Research Interests: Psychology, Cognitive Science, Schizophrenia, Magnetic Resonance Imaging, Creatine, and 15 moreMagnetic Resonance Spectroscopy, Medicine, Emotions, Humans, MR spectroscopy, Female, Male, Volume, Middle Aged, Adult, Choline, Nuclear Magnetic Resonance Imaging, Neurosciences, Gray Matter, and Anterior cingulate cortex
Although there have been many studies surveying the prevalence of specific viral antibodies in a large cohort of patients with schizophrenia, changes in antibody levels during the course of acute illness have not been fully investigated.... more
Although there have been many studies surveying the prevalence of specific viral antibodies in a large cohort of patients with schizophrenia, changes in antibody levels during the course of acute illness have not been fully investigated. We conducted a preliminary study investigating levels of antibodies to 5 herpesviruses (herpes simplex virus type 1, cytomegalovirus, Epstein-Barr virus, varicella-zoster virus and human herpesvirus type 6) and 6 other viruses (measles, rubella, mumps, influenza A and B and Japanese encephalitis viruses) in paired sera of 8 patients with acute onset or exacerbation of schizophrenia. Assay for specific immunoglobulin M (IgM) antibody was also performed for herpesviruses and mumps. Neither any relevant change in antibody levels nor appearance of specific IgM antibody was observed for any of the viruses in any of the patients investigated. It is unlikely that the active infection or reactivation of these viruses has direct causal relationship to schizo...
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Chronic excessive alcohol intake results in alcohol-related brain damage. Many previous reports have documented alcohol-related global or local brain shrinkage or diffusional abnormalities among alcoholics and heavy to moderate drinkers;... more
Chronic excessive alcohol intake results in alcohol-related brain damage. Many previous reports have documented alcohol-related global or local brain shrinkage or diffusional abnormalities among alcoholics and heavy to moderate drinkers; however, the influence of relatively low levels of alcohol consumption on brain structural or diffusional abnormality is unclear. We investigated structural or diffusional abnormalities related to lifetime alcohol consumption (LAC) using voxel-based morphometry (VBM) among Japanese non-alcohol-dependent individuals (114 males, 97 females). High-resolution three-dimensional magnetic resonance images and diffusion tensor imaging were acquired in all subjects. The collected images were normalized, segmented, and smoothed using SPM 5. Gray matter volume (GMV) and white matter volume (WMV) were normalized for each total intracranial volume (TIV), and partial correlation coefficients were estimated between normalized GMV or WMV and lifetime alcohol consumption (LAC) adjusted for age. To investigate regional GMV or WMV abnormalities related to LAC, multiple regression analyses were performed among regional GMV or WMV and LAC, age, and TIV. To investigate subtle regional abnormalities, multiple regression analyses were performed among fractional anisotropy (FA) or mean diffusivity (MD), and LAC and age. No LAC-related global or regional GMV or WMV abnormality or LAC-related regional FA abnormality was found among male or female subjects. Significant LAC-related MD increase was found in the right amygdala among female subjects only. The current results suggest female brain vulnerability to alcohol, and a relation between subtle abnormality in the right amygdala and alcohol misuse.
Research Interests: Computer Science, Brain, Humans, Female, Alcohol Drinking, and 15 moreMale, Alcohol Consumption, Aged, High Resolution, Alcohol dependence, Adult, Fractional Anisotropy, Brain Structure, Gray Matter, Brain Damage, Brain Diseases, Mean Diffusivity, Magnetic resonance image, Diffusion magnetic resonance imaging, and Medical and Health Sciences
Research Interests: Genetics, Bipolar Disorder, Biology, Comparative Study, Cardiovascular disease, and 15 moreBiological Sciences, Association study, Female, Depressive Disorder, Genetic determinism, Gene, Aged, Gen, Genotype, Adult, Age Factors, Asian Continental Ancestry Group, Affective Disorder, alleles, and Gene frequency
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BackgroundThe neurocognitive basis of auditory hallucinations is unclear, but there is increasing evidence implicating abnormalities in processing inner speech. Previous studies have shown that people with schizophrenia who were prone to... more
BackgroundThe neurocognitive basis of auditory hallucinations is unclear, but there is increasing evidence implicating abnormalities in processing inner speech. Previous studies have shown that people with schizophrenia who were prone to auditory hallucinations demonstrated attenuated activation of brain areas during the monitoring of inner speech.AimsTo investigate whether the same pattern of functional abnormalities would be evident as the rate of inner speech production was varied.MethodEight people with schizophrenia who had a history of prominent auditory hallucinations and eight control participants were studied using functional magnetic resonance imaging while the rate of inner speech generation was varied experimentally.ResultsWhen the rate of inner speech generation was increased, the participants with schizophrenia showed a relatively attenuated response in the right temporal, parietal, parahippocampal and cerebellar cortex.ConclusionsIn people with schizophrenia who are p...
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Research Interests: Schizophrenia, Biology, Adolescent, Medicine, Biological Sciences, and 12 moreBiological Psychiatry, Humans, Female, Male, Karyotyping, Genetic linkage analysis, Middle Aged, Adult, Chromosome Banding, Psychiatric Status Rating Scales, Psychology and Cognitive Sciences, and Medical and Health Sciences
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ABSTRACT
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The recent possible neurodevelopmental etiology of schizophrenia makes the neurotrophin-3 (NT-3) gene an interesting candidate locus. We studied the allelic distributions of dinucleotide repeat polymorphism at the NT-3 gene locus in 70... more
The recent possible neurodevelopmental etiology of schizophrenia makes the neurotrophin-3 (NT-3) gene an interesting candidate locus. We studied the allelic distributions of dinucleotide repeat polymorphism at the NT-3 gene locus in 70 patients with schizophrenia and in 70 controls. A highly significant difference between the two groups was observed at the allele A3. Even Bonferroni's correction was used, the difference was still significant. Individuals with homozygous or heterozygous for the allele A3 had a 2.4-fold increased risk of schizophrenia. Determination of NT-3 genotype may help to identify those at greater risk of schizophrenia. Furthermore, this finding supports evidence implicating neurodevelopmental deficit in the pathogenesis of this disorder.
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MRI studies using the manual tracing method have shown a smaller-than-normal hippocampal volume in patients with posttraumatic stress disorder (PTSD). However, these studies have yielded inconsistent results, and brain structures other... more
MRI studies using the manual tracing method have shown a smaller-than-normal hippocampal volume in patients with posttraumatic stress disorder (PTSD). However, these studies have yielded inconsistent results, and brain structures other than the hippocampus have not been well investigated. A recently developed, fully automated method called voxel-based morphometry enables an exploration of structural changes throughout the brain by applying statistical parametric mapping to high-resolution MRI. Here we first used this technology in patients with PTSD. Participants were 9 victims of the Tokyo subway sarin attack with PTSD and 16 matched victims of the same traumatic event without PTSD. The voxel-based morphometry showed a significant gray-matter volume reduction in the left anterior cingulate cortex (ACC) in trauma survivors with PTSD compared with those without PTSD. The severity of the disorder was negatively correlated with the gray-matter volume of the left ACC in PTSD subjects. T...
Research Interests: Anterior Cingulate, Magnetic Resonance Imaging, Emotion Regulation, Medicine, Multidisciplinary, and 15 moreHippocampus, Humans, Posttraumatic stress disorder, Female, Male, Structural Change, Middle Aged, High Resolution, Adult, Functional Neuroimaging, Brain Structure, Gray Matter, Anterior cingulate cortex, Case Control Studies, and Sarin
Research Interests: Schizophrenia, Magnetoencephalography, Magnetic Resonance Imaging, Brain Mapping, Humans, and 15 moreFemale, Neuroimage, Male, Regression Analysis, Mismatch Negativity, High Resolution, Adult, Left Hemisphere, Reference Values, Gray Matter, Functional Laterality, Magnetic resonance image, PLANUM TEMPORALE, Psychology and Cognitive Sciences, and Medical and Health Sciences
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Functional and structural abnormalities of the anterior cingulate gyrus (ACG) in patients with schizophrenia have been repeatedly reported. However, one remaining issue is whether gray matter volume reduction in ACG exists to an extent... more
Functional and structural abnormalities of the anterior cingulate gyrus (ACG) in patients with schizophrenia have been repeatedly reported. However, one remaining issue is whether gray matter volume reduction in ACG exists to an extent comparable with, or even in excess of, that in other prefrontal and temporolimbic regions. High-spatial-resolution magnetic resonance imaging was performed on patients with schizophrenia (n=27) and on age-, gender-, and parental socioeconomic-status-matched healthy control subjects (n=27). After the gray and white matter were semiautomatically segmented, whole prefrontal and temporal lobes were manually parceled into 15 subregions-by-two hemispheres (30 regions of interest) constituting seven prefrontal gray matter regions, six temporal gray matter regions, the prefrontal white matter, and the temporal white matter. Compared with healthy subjects, schizophrenic patients showed significant gray matter volume reduction in the bilateral ACG, this being the largest effect size (left, 0.84; right, 0.56) among all the regions examined. There were also significant gray matter volume reductions in the bilateral posterior STG, bilateral inferior frontal gyrus, left posterior amygdala-hippocampal complex (mostly hippocampus), and the left insula. These results suggest that gray matter volume reductions in the ACG are prominent among prefrontal and temporolimbic regions in patients with schizophrenia. These findings indicate the importance of ACG abnormalities in the pathophysiology of schizophrenia.
Research Interests: Cognitive Science, Anterior Cingulate, Magnetic Resonance Imaging, Comparative Study, Hippocampus, and 15 moreFourier Analysis, Brain, Humans, Effect size, Female, Amygdala, Clinical Sciences, Atrophy, Adult, Inferior frontal gyrus, Limbic System, High Spatial Resolution, Healthy Subjects, Gray Matter, and Magnetic resonance image
Extrapyramidal side-effects (EPS), the most frequent and severe side-effects of antipsychotics, sometimes become irreversible and cause severe psychosocial disturbance in patients with schizophrenia. However, the neurobiological basis of... more
Extrapyramidal side-effects (EPS), the most frequent and severe side-effects of antipsychotics, sometimes become irreversible and cause severe psychosocial disturbance in patients with schizophrenia. However, the neurobiological basis of EPS has not yet been elucidated. In this study, neurochemical correlates of EPS were examined by 1H-MR spectroscopy (1H-MRS). Sixteen medicated patients with schizophrenia and 15 age-, gender- and parental-socioeconomic-status-matched normal controls were examined using single-voxel 1H-MRS. Absolute concentrations of N-acetyl aspartate (NAA), choline-containing compounds (Cho), creatine/phosphocreatine, myo-inositol, and Glx (glutamate and glutamine) in the left putamen were evaluated. The patient group showed mild EPS and no significant metabolic abnormalities in this region. The more severe drug-induced parkinsonism assessed by the Simpson-Angus Scale, however, significantly correlated with the higher Cho concentration and tended to be correlated ...