Mark Rogers

Publications (8)34.74 Total impact

• Article: Disrupted integrity of the fornix is associated with impaired memory organization in schizophrenia.

  Kunio Takei, Hidenori Yamasue, Osamu Abe, Haruyasu Yamada, Hideyuki Inoue, Motomu Suga, Kayoko Sekita, Hiroki Sasaki, Mark Rogers, Shigeki Aoki, Kiyoto Kasai
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  ABSTRACT: The fornix is a major projection of the hippocampus to and from other brain regions. A previous diffusion tensor imaging (DTI) study has reported disrupted integrity of the fornix in patients with schizophrenia. However, functional significance of the DTI abnormalities of the fornix in schizophrenia has not been fully studied yet. We investigated an association between DTI abnormalities of the fornix and impairment of memory organization in schizophrenia. Thirty-one patients with schizophrenia and 65 age- and gender-matched healthy controls underwent DTI, and fractional anisotropy (FA) and mean diffusivity (MD) were measured in cross-sections of fornix tractography. In addition, all of the patients and 32 controls performed a verbal learning task specialized for evaluating memory organization, the verbal memory subscale of the Wechsler Memory Scale-Revised, the category- and letter fluency tests, and the Japanese version of National Adult Reading Test. Statistically significant reduction of FA and increase of MD were found in the fornix of patients with schizophrenia compared with controls with no significant lateralization. A significant patients-specific correlation was found between increased MD in the left fornix and lower scores on utilization of semantic organization in the verbal learning task. In addition, increased MD in the right fornix showed a patients-specific association with poorer performance on the category fluency test, which indexes organization of long-term semantic memory. These patients-specific correlations, however, were not statistically lateralized to either hemisphere. These results indicate that disrupted integrity of the fornix contributes to impaired memory organization in schizophrenia.
  Schizophrenia Research 09/2008; 103(1-3):52-61. · 4.75 Impact Factor
• Article: Gender-common and -specific neuroanatomical basis of human anxiety-related personality traits.

  Hidenori Yamasue, Osamu Abe, Motomu Suga, Haruyasu Yamada, Hideyuki Inoue, Mamoru Tochigi, Mark Rogers, Shigeki Aoki, Nobumasa Kato, Kiyoto Kasai
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  ABSTRACT: Exploration of the relationships between regional brain volume and anxiety-related personality traits is important for understanding preexisting vulnerability to depressive and anxiety disorders. However, previous studies on this topic have employed relatively limited sample sizes and/or image processing methodology, and they have not clarified possible gender differences. In the present study, 183 (male/female: 117/66) right-handed healthy individuals in the third and fourth decades of life underwent structural magnetic resonance imaging scans and Temperament and Character Inventory. Neuroanatomical correlates of individual differences in the score of harm avoidance (HA) were examined throughout the entire brain using voxel-based morphometry. We found that higher scores on HA were associated with smaller regional gray matter volume in the right hippocampus, which was common to both genders. In contrast, female-specific correlation was found between higher anxiety-related personality traits and smaller regional brain volume in the left anterior prefrontal cortex. The present findings suggest that smaller right hippocampal volume underlies the basis for higher anxiety-related traits common to both genders, whereas anterior prefrontal volume contributes only in females. The results may have implications for why susceptibility to stress-related disorders such as anxiety disorders and depression shows gender and/or individual differences.
  Cerebral Cortex 02/2008; 18(1):46-52. · 6.54 Impact Factor
• Article: Association study between the TNXB locus and schizophrenia in a Japanese population.

  Mamoru Tochigi, Xuan Zhang, Jun Ohashi, Hiroyuki Hibino, Takeshi Otowa, Mark Rogers, Tadafumi Kato, Yuji Okazaki, Nobumasa Kato, Katsushi Tokunaga, Tsukasa Sasaki
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  ABSTRACT: The chromosome 6p21-24 region, which contains the human leukocyte antigen (HLA) region, has been suggested as an important locus for a susceptibility gene for schizophrenia. Recently, a significant association between schizophrenia and the TNXB locus, located immediately telomeric of the NOTCH4 locus in the HLA region, was observed. Few studies have further investigated the region in schizophrenia. In the present study, we investigated the region in a Japanese population. Subjects included 241 patients with schizophrenia and 290 controls. Twenty-six single nucleotide polymorphisms (SNPs) and the corresponding haplotypes were analyzed. As a result, exactly the same SNPs in the TNXB locus (rs1009382 and rs204887) as in the previous study were associated with schizophrenia (P = 0.034 and 0.034, respectively, uncorrected). A SNP (rs2071287) in the NOTCH4 locus and haplotype around it were also suggested to associate with the disease, consistent with another previous study (P = 0.041 and permutation P = 0.024, respectively, uncorrected). Although these associations became insignificant after Bonferroni correction, the findings might provide support for the association of the TNXB locus or its adjacent region of the NOTCH4 locus with schizophrenia.
  American Journal of Medical Genetics Part B Neuropsychiatric Genetics 05/2007; 144B(3):305-9. · 3.70 Impact Factor
• Article: Insertional polymorphism of endogenous retrovirus HERV-K115 in schizophrenia.

  Takeshi Otowa, Mamoru Tochigi, Mark Rogers, Tadashi Umekage, Nobumasa Kato, Tsukasa Sasaki
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  ABSTRACT: Retroviruses are implicated in the pathogenesis of schizophrenia. Human endogenous retrovirus type K115 (HERV-K115) is a full-length, potentially transcriptional retrovirus and is also polymorphic. We investigated the frequency of HERV-K115 in Japanese schizophrenia patients and healthy controls. No difference was found in the frequency between patients and controls (8.4% versus 9.4%, respectively). However, a marginal difference was observed in age at onset between the HERV-K positive and negative patients (p=0.057). The HERV-K115 insertion appeared to be more frequent in patients with younger onset than those with later onset. These results preliminarily suggest that HERV-K115 may not be associated with schizophrenia in general, but that it could play a partial role in early precipitation of the disease.
  Neuroscience Letters 12/2006; 408(3):226-9. · 2.11 Impact Factor
• Article: Association study of the dysbindin (DTNBP1) gene in schizophrenia from the Japanese population.

  Mamoru Tochigi, Xuan Zhang, Jun Ohashi, Hiroyuki Hibino, Takeshi Otowa, Mark Rogers, Tadafumi Kato, Yuji Okazaki, Nobumasa Kato, Katsushi Tokunaga, Tsukasa Sasaki
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  ABSTRACT: Dysbindin (DTNBP1: dystrobrevin binding protein 1), located on 6p22.3, is a candidate susceptibility gene for schizophrenia. Several studies, mostly in Caucasians, have provided evidence for an association between schizophrenia and the gene, although no common polymorphism or haploytpe has been established. In Asian populations, two studies investigated a limited number of single nucleotide polymorphisms (SNPs) of dysbindin and observed support for the association. In the present study, we investigated 12 SNPs of dysbindin, including those examined in previous Asian studies, and the corresponding haplotypes in a Japanese people with schizophrenia. As a result, no significant difference was observed between patients and controls in allelic frequencies or genotypic distributions of the 12 SNPs. Permutation test however showed significant differences in frequencies of the estimated 10-marker haplotypes between patients and controls (global p = 0.006). The present study may provide further support for an association between dysbindin and schizophrenia in Asian populations. The results might be similar to a previous Asian study, but specific haplotypes suggested for the association differed between the studies. Studies with more markers and subjects may be required before firm conclusions can be reached.
  Neuroscience Research 11/2006; 56(2):154-8. · 2.25 Impact Factor
• Source

  Available from: Tsukasa Sasaki

  Article: No evidence for an association between the BDNF Val66Met polymorphism and schizophrenia or personality traits.

  Mamoru Tochigi, Takeshi Otowa, Motomu Suga, Mark Rogers, Takanobu Minato, Hidenori Yamasue, Kiyoto Kasai, Nobumasa Kato, Tsukasa Sasaki
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  ABSTRACT: Brain-derived neurotrophic factor (BDNF) is a member of the nerve growth factor family, which plays a critical role in neurodevelopment. Based on the neurodevelopmental hypothesis, the BDNF gene has been a candidate locus for schizophrenia. In Caucasians, recent studies identified an association with the Val66Met polymorphism, which has been suggested to affect episodic memory and hippocampal function in humans. However, in other populations, the association has not been replicated. In the present study, we investigated the association between the Val66Met polymorphism of the gene and schizophrenia in 401 Japanese patients with schizophrenia and 569 controls. As a result, we did not observe a significant difference in genotypic distribution or allele frequencies between the patients and controls (chi2=0.56, df=2, p=0.76 and chi2=0.39, df=1, p=0.53, respectively). We also investigated the association between the polymorphism and personality traits in the controls; however, no significant association was observed. Thus, the present study did not provide evidence for an association between the BDNF gene and schizophrenia or personality traits in the Japanese population.
  Schizophrenia Research 11/2006; 87(1-3):45-7. · 4.75 Impact Factor
• Article: Parahippocampal activation evoked by masked traumatic images in posttraumatic stress disorder: a functional MRI study.

  Hideshi Sakamoto, Rin Fukuda, Tomoyuki Okuaki, Mark Rogers, Kiyoto Kasai, Toru Machida, Ichiro Shirouzu, Hidenori Yamasue, Tsuyoshi Akiyama, Nobumasa Kato
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  ABSTRACT: Posttraumatic stress disorder (PTSD) has been widely studied, but its neural mechanism is still unclear. The purpose of this study is to identify dysfunctional areas in PTSD throughout the whole brain to help to elucidate the neural mechanisms of PTSD. Sixteen patients with PTSD and sixteen healthy controls participated in this study. Traumatic images under perceptual threshold including scenes of earthquakes, traffic accidents, ambulances, emergency rooms, and crimes were presented to the participants, and brain activation was measured using functional MRI. Functional brain images of both groups were evaluated with random effect analysis for the whole brain. In the control group, activation in the ventral frontoparietal areas correlated significantly with presentation of the masked traumatic stimuli. In the PTSD group, activation was not observed in these areas, but significant activation correlated with the masked traumatic stimuli in the parahippocampal region including the left parahippocampal gyrus and tail of the left hippocampus. These results suggest that in PTSD patients activation in the ventral frontoparietal network associated with visual attention processing is attenuated, while the left hippocampal area associated with episodic and autobiographical memory is abnormally easily activated. This pattern of activation corresponds well to the clinical characteristics of PTSD, in which even slight traumatic stimuli tend to induce intrusive recollection or flashbacks, despite a general decrease in attention and ability to concentrate.
  NeuroImage 08/2005; 26(3):813-21. · 5.89 Impact Factor
• Article: Seasonality of schizophrenia births in the Japanese population: increased winter births possibly confined to the north area.

  Mamoru Tochigi, Takashi Onai, Kaori Narita, Hiroyuki Hibino, Mark Rogers, Tadashi Umekage, Kazuhisa Kohda, Toshiyuki Otani, Ryo Kanamori, Nobumasa Kato, Tsukasa Sasaki
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  ABSTRACT: A number of North American and European studies have observed a higher proportion of winter births in schizophrenia patients. Thus, seasonal fluctuation of unknown environmental factors may affect brain development in ways that alter susceptibility to schizophrenia. Specification of these factors may help elucidate the etiopathological mechanism of the disease, about which little is certain. A small number of studies have investigated this issue in Asian populations, and the findings are not as consistent as those of Western populations. No remarkable excess of winter births has been observed in Japanese or Korean studies, while some studies have reported a significant decrease of summer births. We further investigated the issue in Japanese patients with schizophrenia (n=3927). No significant excess of winter births was observed, but a decrease in the summer births was found in male subjects. This is largely consistent with previous Japanese studies; however, when the subjects were confined to those born in a colder and higher latitude area of Japan (n=1338), a consistent trend for both a winter increase, and a summer decrease, was found. However, the results did not consistently reach statistical significance, possibly due to the lack of statistical power. Environmental factors that correlate with latitude might play a role in the development of the seasonality of births in schizophrenia. Further studies in a larger sample size are required to test these possibilities.
  Schizophrenia Research 07/2005; 75(2-3):433-8. · 4.75 Impact Factor