-
Ryota Hashimoto,
Kazutaka Ohi,
Yuka Yasuda,
Motoyuki Fukumoto,
Hidenaga Yamamori,
Hidetoshi Takahashi,
Masao Iwase,
Tomo Okochi,
Hiroaki Kazui, Osamu Saitoh,
Masahiko Tatsumi,
Nakao Iwata,
Norio Ozaki,
Kunitoshi Kamijima,
Hiroshi Kunugi,
Masatoshi Takeda
[show abstract]
[hide abstract]
ABSTRACT: The pathogenesis of schizophrenia is thought to involve aberrant immune and inflammatory responses. Nuclear factor kappa B (NF-κB) has important roles in the immune and inflammatory responses. The v-rel avian reticuloendotheliosis viral oncogene homolog A (RELA) gene encodes the major component of the NF-κB complex. We genotyped four single-nucleotide polymorphisms (SNPs) in the RELA gene and performed a gene-based association analysis using 1224 patients with schizophrenia and 1663 controls. We found significant associations of three SNPs (rs11820062: p=0.00011, rs2306365: p=0.0031, and rs7119750: p=0.0080) with schizophrenia and stronger evidence for association in a multi-marker sliding window haplotype analysis (the lowest p=0.00006). The association between this gene and schizophrenia was evident in male subjects but not in female subjects, when separately analyzed by gender. In silico genotype-gene expression analysis using web database and the WGAViewer software revealed that these three schizophrenia-associated SNPs might be related to RELA mRNA expression in immortalized B-lymphocytes. In silico analysis also suggested the putative promoter SNP, rs11820062, might disrupt the consensus transcription factor binding sequence of the androgen receptor. The impact of four RELA polymorphisms on pre-pulse inhibition (PPI) was investigated in 53 patients with schizophrenia. We provided evidence that at risk genotypes of three SNPs were associated with deficits in PPI; however, there was no effect of the one non-risk SNP on PPI. These findings suggest that variants of the RELA gene are associated with risk for schizophrenia and PPI deficits in a Japanese population.
Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 05/2011; 36(9):1921-31. · 6.99 Impact Factor
-
Ryota Hashimoto,
Hitoshi Hashimoto,
Norihito Shintani,
Kazutaka Ohi,
Hiroaki Hori, Osamu Saitoh,
Asako Kosuga,
Masahiko Tatsumi,
Nakao Iwata,
Norio Ozaki,
Kunitoshi Kamijima,
Akemichi Baba,
Masatoshi Takeda,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: Pituitary adenylate cyclase-activating polypeptide (PACAP, ADCYAP1: adenylate cyclase-activating polypeptide 1) is a neuropeptide with neurotransmission modulating activity. The associations of the PACAP gene with schizophrenia and hippocampal volume have been reported. We recently reported depression-like behavior in the forced swimming test in PACAP deficient mice. Here we examined a possible association between the PACAP gene and major depressive disorder (MDD) in 637 patients and 967 controls and found that a genetic variant in the gene was associated with MDD. The present results suggest that PACAP signaling might contribute to the pathogenesis of MDD.
Neuroscience Letters 11/2009; 468(3):300-2. · 2.11 Impact Factor
-
Kazutaka Ohi,
Ryota Hashimoto,
Yuka Yasuda,
Hidenaga Yamamori,
Hiroaki Hori, Osamu Saitoh,
Masahiko Tatsumi,
Masatoshi Takeda,
Nakao Iwata,
Norio Ozaki,
Kunitoshi Kamijima,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: The Bcl2-interacting killer (BIK) gene interacts with cellular and viral survival-promoting proteins, such as Bcl-2, to enhance apoptosis. The BIK protein promotes cell death in a manner analogous to Bcl-2-related death-promoting proteins, Bax and Bak. There have been lower Bcl-2 levels and increased Bax/Bcl-2 ratio in the temporal cortex of patients with schizophrenia compared with those in controls. Because the death-promoting activity of BIK was suppressed in the presence of the cellular and viral survival-promoting proteins, the BIK protein is suggested as a likely target for antiapoptotic proteins. The purpose of this study is to investigate the association between genetic variants in the BIK gene and schizophrenia in a large Japanese population (1181 patients with schizophrenia and 1243 healthy controls). We found nominal evidence for association of alleles, rs926328 (chi2=4.44, p=0.035, odds ratio=1.13) and rs2235316 (chi2=4.41, p=0.036, odds ratio=1.13), with schizophrenia. However, these associations were no longer positive after correction for multiple testing (rs926328: corrected p=0.105, rs2235316: corrected p=0.108). We conclude that BIK might not play a major role in the susceptibility of schizophrenia in Japanese population.
Neuroscience Letters 08/2009; 463(1):60-3. · 2.11 Impact Factor
-
Ryota Hashimoto,
Hiroko Noguchi,
Hiroaki Hori,
Tetsuo Nakabayashi,
Tatsuyo Suzuki,
Nakao Iwata,
Norio Ozaki,
Asako Kosuga,
Masahiko Tatsumi,
Kunitoshi Kamijima,
Seiichi Harada,
Masatoshi Takeda, Osamu Saitoh,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: Schizophrenia is a common psychiatric disorder characterized by disturbances of cognition, emotion and social functioning. There are few studies investigating a possible genetic basis for the underlying mechanism of cognitive dysfunctions. A genetic variation in the dysbindin gene (DTNBP1: dystrobrevin binding protein 1), a susceptibility gene for schizophrenia, has been reported to be associated with general cognitive ability and cognitive decline in patients with schizophrenia. Although profound disturbances of memory performance are observed in schizophrenia, only one study has reported a relationship between this gene and spatial working memory in a Caucasian population. We examined a possible association between a protective haplotype of DTNBP1 for developing schizophrenia and memory performance measured by the Wechsler Memory Scale-Revised (WMS-R) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) in 165 healthy volunteers and 70 patients with schizophrenia in a Japanese population. Healthy controls that carry the protective haplotype showed higher performance in several memory domains measured by the WMS-R than those who did not. Genotype effect on memory performance was not observed in patients with schizophrenia. This haplotype did not affect IQ and its sub-scores as measured by the Wechsler Adult Intelligence Scale-Revised in both groups. These data suggest that DTNBP1 may have impact on parts of memory functions.
The World Journal of Biological Psychiatry 05/2009; 11(2 Pt 2):431-8. · 2.38 Impact Factor
-
Ryota Hashimoto,
Takeyuki Mori,
Kiyotaka Nemoto,
Yoshiya Moriguchi,
Hiroko Noguchi,
Tetsuo Nakabayashi,
Hiroaki Hori,
Seiichi Harada,
Hiroshi Kunugi, Osamu Saitoh,
Takashi Ohnishi
[show abstract]
[hide abstract]
ABSTRACT: There has been a hypothesis that deficits in the basal ganglia-thalamic system may play an important role in the dysfunctional goal-directed behaviour in schizophrenia. By using diffusion tensor imaging, we measured fractional anisotropy (FA) values in the basal ganglia-thalamic system in 42 schizophrenics and 42 matched controls to investigate microstructural tissue alterations in the basal ganglia-thalamic system in schizophrenia. Schizophrenics had significantly lower FA values in the bilateral globus pallidus and left thalamus compared to controls, suggesting that schizophrenics might have microstructural abnormalities in globus pallidus and thalamus. These data support the notion that myelination abnormalities in basal ganglia-thalamic system are related to the pathophysiology of schizophrenia.
The World Journal of Biological Psychiatry 02/2009; 10(1):65-9. · 2.38 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Previous studies suggested that genetic variations in the 5' region of Epsin 4, a gene encoding enthoprotin on chromosome 5q33, are associated with schizophrenia. However, conflicting results have also been reported. We examined the possible association in a Japanese sample of 354 patients and 365 controls. Seventeen polymorphisms of Epsin 4 [3 microsatellites and 14 single nucleotide polymorphisms (SNPs)] were selected. A microsatellite marker (D5S1403) demonstrated a significant difference in the allele frequency between patients and controls (uncorrected P = 0.04). However, there was no significant difference in the genotype or allele frequency between the two groups for the other microsatellites or SNPs. Haplotype-based analysis provided no evidence for an association. The positive result at D5S1403 no longer reached statistical significance when multiple testing was taken into consideration. Our results suggest that the examined region of Epsin 4 does not have a major influence on susceptibility to schizophrenia in Japanese.
Acta Neurovegetativa 10/2008; 115(9):1347-54. · 2.73 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The Temperament and Character Inventory (TCI) is a well-established self-report questionnaire measuring four temperament and three character dimensions. However, surprisingly few studies have used it to examine the personality of patients with schizophrenia, and none in Japan. Moreover, possible gender differences in personality among patients with schizophrenia have not been well documented. We administered the TCI to 86 Japanese patients with schizophrenia and 115 age- and gender-matched healthy controls to characterize personality traits in patients with schizophrenia and to examine their relationships with clinical variables, particularly gender and symptoms. Compared with controls, patients demonstrated significantly lower novelty seeking, reward dependence, self-directedness and cooperativeness, and higher harm avoidance and self-transcendence. Male patients showed even more pronounced personality alteration than female patients when both of them were compared with healthy people. Personality dimensions were moderately correlated with symptom dimensions assessed by the Positive and Negative Syndrome Scale (PANSS). These results, together with prior findings in several other countries, suggest that schizophrenia patients have a unique personality profile which appears to be present across cultures and that the greater alteration of personality in schizophrenia males might be related to their poorer social and community functioning.
Psychiatry Research 09/2008; 160(2):175-83. · 2.52 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Schizophrenia is characterized by a series of serious mental disturbances, including social, cognitive, and emotional dysfunctions. Although motor dysfunctions as well as the cognitive impairments in schizophrenia have been noted since the era of Kraepelin, little attention has been paid to motor dysfunctions until recently. Here, we examined the characteristics of motor dysfunctions and their relationship to other cognitive functions in schizophrenia. Subjects were 27 patients who met the DSM-IV criteria for schizophrenia and 49 healthy volunteers. A series of motor tests, i.e., pegboard, mirror drawing, normal drawing, and finger movement tests, were administered, and cognitive functions were assessed with the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale Revised and the Wisconsin Card Sorting Test. The finger movement test is a novel motor test that we developed to assess motor dexterity independent of motor speed. A stepwise discriminant analysis revealed that the finger movement and delayed recall tests were able to distinguish patients and controls most effectively. The scores of these two tests showed no correlation. Educational level was correlated with the delayed recall score, but not with the finger movement score. A significant difference was observed in the finger movement test score between inpatients and outpatients. There was no significant correlation between dosage of antipsychotic drugs and finger movement score in the patient group. The present results suggest that impairment in motor dexterity is a major characteristic of schizophrenia, which might be independent of cognitive functions.
Psychiatry Research 07/2008; 159(3):281-9. · 2.52 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The extent of IQ decline due to the development of illness in patients with chronic schizophrenia and the degree of memory impairment relative to such IQ decline still remain unclear. Our results suggest that schizophrenia patients experience marked IQ decline due to the development of illness and their wide-ranging memory impairments are even more severe than the IQ decline.
Psychiatry Research 04/2008; 158(2):251-5. · 2.52 Impact Factor
-
Aiko Izumi,
Yoshimi Iijima,
Hiroko Noguchi,
Tadahiro Numakawa,
Takeya Okada,
Hiroaki Hori,
Tadafumi Kato,
Masahiko Tatsumi,
Asako Kosuga,
Kunitoshi Kamijima,
Takashi Asada,
Kunimasa Arima, Osamu Saitoh,
Sadao Shiosaka,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: Human neuropsin (NP) (hNP) has been implicated in the progressive change of cognitive abilities during primate evolution. The hNP gene maps to chromosome 19q13, a region reportedly linked to schizophrenia and bipolar disorder. Therefore, hNP is a functional and positional candidate gene for association with schizophrenia, mood disorders, and cognitive ability. Polymorphism screening was performed for the entire hNP gene. The core promoter region was determined and whether or not transcriptional activity alters in an allele-dependent manner was examined by using the dual-luciferase system. Allelic and genotypic distributions of five single-nucleotide polymorphisms (SNPs) were compared between patients with schizophrenia (n=439), major depression (n=409), bipolar disorder (n=207), and controls (n=727). A possible association of the hNP genotype with memory index (assessed with Wechsler Memory Scale, revised, WMS-R) and intelligence quotient (IQ assessed with Wechsler Adult Intelligence Scale, revised; WAIS-R) was examined in healthy controls (n=166). A total of 28 SNPs, including nine novel SNPs, were identified. No significant effects on transcriptional activity were observed for SNPs in the promoter region. A significant allelic association was found between several SNPs and bipolar disorder (for SNP23 at the 3' regulatory region; odds ratio 1.48, 95% confidential interval 1.16-1.88, P=0.0015). However, such an association was not detected for schizophrenia or depression. Significant differences were observed between SNP23 and attention/concentration sub-scale score of WMS-R (P=0.016) and verbal IQ (P<0.001). Genetic variation of the hNP gene may contribute to molecular mechanisms of bipolar disorder and some aspects of memory and intelligence.
Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 03/2008; 33(13):3237-45. · 6.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Prepulse inhibition (PPI) of acoustic startle reflex has been suggested as a neurophysiologic measure of information processing abnormalities in schizophrenia. However, there has been little information on PPI and related measures in Asian patients with schizophrenia. We examined startle response to acoustic stimuli, its habituation, and PPI in 20 Japanese patients with chronic schizophrenia under antipsychotic medication and 16 healthy controls matched for age and sex. We measured PPI with 115 dB of pulse (40 ms), 82, 86, or 90 dB of prepulse (20 ms) and 30, 60, or 120 ms of lead interval (LI). The startle response to pulse alone trials was significantly smaller in schizophrenics than in controls, which may be due, at least in part, to medication. There was no significant difference in habituation of startle response during the test session between the two groups. PPI differed significantly between the two groups when LI was 120 ms. No significant relationship was found on startle response or PPI with age of onset, number of previous admission, medication dosages, or symptom scores assessed with the Positive and Negative Syndrome Scale (PANSS). Our results confirm impaired PPI in chronic schizophrenia patients compared with controls in Japanese.
Neuroscience Research 10/2007; 59(1):23-8. · 2.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Plexins are receptors for multiple classes of semaphorins, either alone or in combination with neuropilins. Plexins participate in many cellular events that include axonal repulsion, axonal attraction, cell migration, axon pruning, and synaptic plasticity. PLXNA2 maps to chromosome 1q32. Several linkage studies reported schizophrenia susceptibility loci in the 1q22-42 region. A recent study reported that intronic single nucleotide polymorphisms (SNPs) of PLXNA2 were associated with schizophrenia in a European American population. We attempted to replicate this finding in a Japanese sample of 336 patients with schizophrenia and 304 controls. In addition, we examined 3 non-synonymous SNPs (Arg5Gln, GLn57Arg, and Ala267Thr) in PLXNA2. Genotyping was performed by the TaqMan allelic discrimination assay. There was no significant difference in genotype or allele distribution of either the 4 intronic SNPs or the 3 non-synonymous SNPs between patients and controls. Furthermore, haplotype-based analyses did not provide evidence for an association. These results suggest that PLXNA2 may not play a major role in the development of schizophrenia in our Japanese sample.
Progress in Neuro-Psychopharmacology and Biological Psychiatry 06/2007; 31(4):873-7. · 3.25 Impact Factor
-
Takeyuki Mori,
Takashi Ohnishi,
Ryota Hashimoto,
Kiyotaka Nemoto,
Yoshiya Moriguchi,
Hiroko Noguchi,
Tetsuo Nakabayashi,
Hiroaki Hori,
Seichi Harada, Osamu Saitoh,
Hiroshi Matsuda,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: Recent magnetic resonance imaging (MRI) studies using diffusion tensor imaging (DTI) have suggested reduced fractional anisotropy (FA) in the white matter (WM) of the brain in patients with schizophrenia. We tried to examine whether such reduction in FA exists and whether such changes in FA progress in an age-dependent manner in a Japanese sample of chronic schizophrenia. FA values were compared between 42 patients with chronic schizophrenia and 42 controls matched for age and gender, by using DTI with voxel-by-voxel and region-of-interest analyses. Correlations of FA values with age and duration of illness were examined. Patients with schizophrenia showed lower FA values, compared to controls, in the widespread WM areas including the uncinate fasciculi and cingulum bundles. A significant group-by-age interaction was found for FA in the WM, i.e., age-related reduction of FA was more pronounced in schizophrenics than in controls. A significant negative correlation between FA and duration of illness was also found in the WM. Our data confirmed decreased FA in schizophrenics, compared to controls in the widespread WM areas. Such decreased FA values in schizophrenia might be attributable, at least in part, to progressive changes after the onset of the illness.
Psychiatry Research 03/2007; 154(2):133-45. · 2.52 Impact Factor
-
Hiroaki Hori,
Hiroko Noguchi,
Ryota Hashimoto,
Tetsuo Nakabayashi,
Mayu Omori,
Sho Takahashi,
Ryotaro Tsukue,
Kimitaka Anami,
Naotsugu Hirabayashi,
Seiichi Harada, Osamu Saitoh,
Masao Iwase,
Osami Kajimoto,
Masatoshi Takeda,
Shigeo Okabe,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: Antipsychotic polypharmacy and excessive dosing still prevail worldwide in the treatment of schizophrenia, while their possible association with cognitive function has not well been examined. We examined whether the "non-standard" use of antipsychotics (defined as antipsychotic polypharmacy or dosage >1,000 mg/day of chlorpromazine equivalents) is associated with cognitive function. Furthermore, we compared cognitive function between patients taking only atypical antipsychotics and those taking only conventionals. Neurocognitive functions were assessed in 67 patients with chronic schizophrenia and 92 controls using the Wechsler Memory Scale-Revised (WMS-R), the Wechsler Adult Intelligence Scale-Revised (WAIS-R), the Wisconsin Card Sorting Test (WCST), and the Advanced Trail Making Test (ATMT). Patients showed markedly poorer performance than controls on all these tests. Patients on non-standard antipsychotic medication demonstrated poorer performance than those on standard medication on visual memory, delayed recall, performance IQ, and executive function. Patients taking atypical antipsychotics showed better performance than those taking conventionals on visual memory, delayed recall, and executive function. Clinical characteristics such as duration of medication, number of hospitalizations, and concomitant antiparkinsonian drugs were different between the treatment groups (both dichotomies of standard/non-standard and conventional/atypical). These results provide evidence for an association between antipsychotic medication and cognitive function. This association between antipsychotic medication and cognitive function may be due to differential illness severity (e.g., non-standard treatment for severely ill patients who have severe cognitive impairment). Alternatively, poorer cognitive function may be due in part to polypharmacy or excessive dosing. Further investigations are required to draw any conclusions.
Schizophrenia Research 10/2006; 86(1-3):138-46. · 4.75 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has been studied to identify areas related to EEG events. EEG data recorded in the magnetic resonance (MR) scanner with MR imaging is suffered from two specific artifacts, imaging artifact, and ballistocardiogram (BCG). In this paper, we focus on BCG. In preceding studies, average subtraction was often used for this purpose. However, average subtraction requires an assumption that BCG waveforms are precisely periodic, which seems unrealistic because BCG is a biomedical artifact. We propose the application of independent component analysis (ICA) with a postprocessing of high-pass filtering for the removal of BCG. With this approach, it is not necessary to assume that the BCG waveform is periodic. Empirically, we show that our proposed method removes BCG artifacts as well as does the average subtraction method. Power spectral density analysis of the two approaches shows that, with ICA, distortion of recovered EEG data is also as small as that associated with the average subtraction approach. We also propose a hypothesis for how head movement causes BCGs and show why ICA can remove BCG artifacts arising from this source.
IEEE Transactions on Biomedical Engineering 08/2006; 53(7):1294-308. · 2.28 Impact Factor
-
Takashi Ohnishi,
Ryota Hashimoto,
Takeyuki Mori,
Kiyotaka Nemoto,
Yoshiya Moriguchi,
Hidehiro Iida,
Hiroko Noguchi,
Tetsuo Nakabayashi,
Hiroaki Hori,
Mayu Ohmori,
Ryoutaro Tsukue,
Kimitaka Anami,
Naotugu Hirabayashi,
Seiichi Harada,
Kunimasa Arima, Osamu Saitoh,
Hiroshi Kunugi
[show abstract]
[hide abstract]
ABSTRACT: The catechol-O-methyl transferase (COMT) gene is considered to be a promising schizophrenia susceptibility gene. A common functional polymorphism (Val158Met) in the COMT gene affects dopamine regulation in the prefrontal cortex (PFC). Recent studies suggest that this polymorphism contributes to poor prefrontal functions, particularly working memory, in both normal individuals and patients with schizophrenia. However, possible morphological changes underlying such functional impairments remain to be clarified. The aim of this study was to examine whether the Val158Met polymorphism of the COMT gene has an impact on brain morphology in normal individuals and patients with schizophrenia. The Val158Met COMT genotype was obtained for 76 healthy controls and 47 schizophrenics. The diagnostic effects, the effects of COMT genotype and the genotype-diagnosis interaction on brain morphology were evaluated by using a voxel-by-voxel statistical analysis for high-resolution MRI, a tensor-based morphometry. Patients with schizophrenia demonstrated a significant reduction of volumes in the limbic and paralimbic systems, neocortical areas and the subcortical regions. Individuals homozygous for the Val-COMT allele demonstrated significant reduction of volumes in the left anterior cingulate cortex (ACC) and the right middle temporal gyrus (MTG) compared to Met-COMT carriers. Significant genotype-diagnosis interaction effects on brain morphology were noted in the left ACC, the left parahippocampal gyrus and the left amygdala-uncus. No significant genotype effects or genotype-diagnosis interaction effects on morphology in the dorsolateral PFC (DLPFC) were found. In the control group, no significant genotype effects on brain morphology were found. Schizophrenics homozygous for the Val-COMT showed a significant reduction of volumes in the bilateral ACC, left amygdala-uncus, right MTG and left thalamus compared to Met-COMT schizophrenics. Our findings suggest that the Val158Met polymorphism of the COMT gene might contribute to morphological abnormalities in schizophrenia.
Brain 03/2006; 129(Pt 2):399-410. · 9.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Vesicular monoamine transporters (VMATs) mediate accumulation of monoamines such as serotonin, dopamine, adrenaline, and noradrenaline from the cytoplasm into storage organelles. The VMAT1 (alternatively solute carrier family 18: SLC18A1) regulates such biogenic amines in neuroendocrine systems. The VMAT1 gene maps to chromosome 8p21.3, a locus with strong evidence of linkage with schizophrenia. A recent study reported that a non-synonymous single nucleotide polymorphism (SNP) of the gene (Pro4Thr) was associated with schizophrenia.
We attempted to replicate this finding in a Japanese sample of 354 schizophrenics and 365 controls. In addition, we examined 3 other non-synonymous SNPs (Thr98Ser, Thr136Ile, and Val392Leu). Genotyping was performed by the TaqMan allelic discrimination assay.
There was no significant difference in genotype or allele distribution of the three SNPs of Pro4Thr, Thr136Ile, or Val392Leu between patients and controls. There was, however, a significant difference in genotype and allele distributions for the Thr98Ser polymorphism between the two groups (P = 0.01 for genotype and allele). When sexes were examined separately, significant differences were observed in females (P = 0.006 for genotype, P = 0.003 for allele), but not in males. The Thr98 allele was more common in female patients than in female controls (odds ratio 1.69, 95% CI 1.19-2.40, P = 0.003). Haplotype-based analyses also provided evidence for a significant association in females.
We failed to replicate the previously reported association of Pro4Thr of the VMAT1 gene with schizophrenia. However, we obtained evidence for a possible role of the Thr98Ser in giving susceptibility to schizophrenia in women.
Behavioral and Brain Functions 02/2006; 2:39. · 2.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A mismatch between auditory sensation and expectant imagery of syllables elicited a possible equivalent of mismatch negativity in a previous study. The purpose of this study was to verify whether auditory imagery from musical notation could also mediate such imagery-based mismatch negativity. Neuromagnetic recording was obtained from eight musicians, who were instructed to identify unpredictably occurring pitch mismatches between a random tone sequence and a visually presented musical score. The difference between incongruent and congruent responses showed a magnetic distribution consistent with two frontal-negative current dipoles bilaterally located in the vicinity of Heschl's gyrus, peaking at approximately 150 ms in latency. This imagery-based mismatch negativity may represent an early neural process of deviance detection between the sensory input and expectant imagery.
Neuroreport 09/2005; 16(11):1175-8. · 1.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: During silent reading, visual information provided by letters is converted to auditory information in the mind. The purpose of this study was to identify the primary locus for auditory verbal imagery in the brain. Neuromagnetic recording was obtained from 10 right-handed study participants, who were instructed to identify infrequently occurring phonological mismatches between a random-ordered sequence of syllable sounds and a visually presented syllabogram sequence. The activity difference in early latency, calculated by subtracting the averaged responses to matched syllables from the averaged responses to mismatched syllables, showed a spatiotemporal profile strikingly similar to that of mismatch negativity. Auditory imagery of forthcoming verbal sounds may establish a memory trace as a template for imagery-based mismatch negativity generation in the auditory cortex.
Neuroreport 06/2005; 16(8):803-6. · 1.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Ballistocardiogram and imaging artifacts cause major interference with simultaneous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) recording. In particular, the large amplitude of the imaging artifact precludes easy retrieval of EEG signals during fMRI scanning. Recording with 20,000-Hz digitization rate combined with 3000-Hz low-pass filter revealed the real waveform of the imaging artifact, in which it was elucidated that each artifact peak precisely corresponded to each gradient component and actually had differential waveforms of the original gradient pulses. Based on this finding, to retrieve EEG signal during fMRI acquisition, a blip-type echo planar sequence was modified so that EEG sampling might be performed at every 1000 micros (digitization rate 1000 Hz) exclusively in the period in which the artifact resided around the baseline level. This method, called "stepping stone sampling," substantially attenuated the amplitude of the imaging artifact. The remnant of the artifact was subtracted from the averaged artifact waveform. In human studies, alpha activity was successfully retrieved by inspection, and its attenuation/augmentation was observed during eyes open/closed periods. Fast Fourier transform analysis further revealed that even from DC up to 120 Hz, retrieved EEG data during scanning had very similar power distributions to the data retrieved during no scanning, implying the availability of the high-frequency band of the retrieved EEG signals, including even the gamma band.
NeuroImage 07/2003; 19(2 Pt 1):281-95. · 5.89 Impact Factor
