Hirotaka Kosaka

University of Fukui, Hukui, Fukui, Japan

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Publications (51)159.69 Total impact

  • Journal of clinical psychopharmacology 04/2014; · 5.09 Impact Factor
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    ABSTRACT: Background: Bipolar disorder (BD) has been linked with the manifestation of catatonia in subjects with autism spectrum disorders (ASD). Idiopathic basal ganglia calcification (IBGC) is characterized by movement disorders and various neuropsychiatric disturbances including mood disorder. Case: We present a patient with ASD and IBGC who developed catatonia presenting with prominent dystonic feature caused by comorbid BD, which was treated effectively with quetiapine. Conclusion: In addition to considering the possibility of neurodegenerative disease, careful psychiatric interventions are important to avoid overlooking treatable catatonia associated with BD in cases of ASD presenting with both prominent dystonic features and apparent fluctuation of the mood state.
    Brain & development 01/2014; · 1.74 Impact Factor
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    ABSTRACT: While patients with major depressive disorder typically have a reduced hippocampal volume, particularly in the cornu ammonis 1 (CA1), animal studies suggest that depressive mood is related to the dentate gyrus (DG). In this study, our objective was to clarify which hippocampal subregions are functionally associated with depressive mood in humans. We conducted a functional MRI (fMRI) study on 27 cognitively intact volunteers. Subjects performed a modified version of a delayed matching-to-sample task in an MRI scanner to investigate pattern separation-related activity during each phase of encoding, delay, and retrieval. In each trial, subjects learned a pair of sample cues. Functional MR images were acquired at a high spatial resolution, focusing on the hippocampus. Subjects also completed the Beck Depression Inventory (BDI), a questionnaire about depressive mood. Depending on the similarity between sample cues, activity in the DG/CA3 and medial CA1 in the anterior hippocampus changed only during encoding. Furthermore, the DG/CA3 region was more active during successful encoding trials compared to false trials. Activity in the DG/CA3 and lateral CA1 was negatively correlated with BDI scores. These results suggest that the DG/CA3 is the core region for pattern separation during the encoding phase and interacts with the medial CA1, depending on the similarity of the stimuli, in order to achieve effective encoding. Impaired activity in the DG/CA3, as well as in the lateral CA1, was found to be associated with depressive symptoms, even at a subclinical level. (238 words).
    Hippocampus 10/2013; · 5.49 Impact Factor
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    ABSTRACT: The objective of this study was to examine differences in episodic memory retrieval between individuals with autism spectrum disorder (ASD) and typically developing (TD) individuals. Previous studies have shown that personality similarities between readers and characters facilitated reading comprehension. Highly extraverted participants read stories featuring extraverted protagonists more easily and judged the outcomes of such stories more rapidly than did less extraverted participants. Similarly, highly neurotic participants judged the outcomes of stories with neurotic protagonists more rapidly than did participants with low levels of neuroticism. However, the impact of the similarity effect on memory retrieval remains unclear. This study tested our 'similarity hypothesis', namely that memory retrieval is enhanced when readers with ASD and TD readers read stories featuring protagonists with ASD and with characteristics associated with TD individuals, respectively. Eighteen Japanese individuals (one female) with high-functioning ASD (aged 17 to 40 years) and 17 age- and intelligence quotient (IQ)-matched Japanese (one female) TD participants (aged 22 to 40 years) read 24 stories; 12 stories featured protagonists with ASD characteristics, and the other 12 featured TD protagonists. Participants read a single sentence at a time and pressed a spacebar to advance to the next sentence. After reading all 24 stories, they were asked to complete a recognition task about the target sentence in each story. To investigate episodic memory in ASD, we analyzed encoding based on the reading times for and readability of the stories and retrieval processes based on the accuracy of and response times for sentence recognition. Although the results showed no differences between ASD and TD groups in encoding processes, they did reveal inter-group differences in memory retrieval. Although individuals with ASD demonstrated the same level of accuracy as did TD individuals, their patterns of memory retrieval differed with respect to response times. Individuals with ASD more effectively retrieved ASD-congruent than ASD-incongruent sentences, and TD individuals retrieved stories with TD more effectively than stories with ASD protagonists. Thus, similarity between reader and story character had different effects on memory retrieval in the ASD and TD groups.
    Molecular autism. 06/2013; 4(1):20.
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    ABSTRACT: Patients with autism spectrum disorders (ASDs) exhibit core autistic symptoms including social impairments from early childhood and mostly show secondary disabilities such as irritability and aggressive behavior based on core symptoms. However, there are still no radical treatments of social impairments in these patients. Oxytocin has been reported to play important roles in multiple social behaviors dependent on social recognition, and has been expected as one of the effective treatments of social impairments of patients with ASDs. We present a case of a 16-year-old girl with autistic disorder who treated by long-term administration of oxytocin nasal spray. Her autistic symptoms were successfully treated by two month administration; the girl's social interactions and social communication began to improve without adverse effects. Her irritability and aggressive behavior also improved dramatically with marked decreases in aberrant behavior checklist scores from 69 to 7. This case is the first to illustrate long-term administration of oxytocin nasal spray in the targeted treatment of social impairments in a female with autistic disorder. This case suggests that long-term nasal oxytocin spray is promising and well-tolerated for treatment of social impairments of patients with ASDs.
    BMC Psychiatry 08/2012; 12:110. · 2.23 Impact Factor
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    ABSTRACT: Subjects with Pervasive Developmental Disorders (PDD) often exhibit behavioral symptoms such as aggressiveness and irritability, which are targets of psychopharmacologic intervention. This retrospective study was designed to examine children and adolescents with PDD experiencing tolerability issues with risperidone treatment, and thereby assess the efficacy and tolerability of switching to aripiprazole. This naturalistic study included 23 subjects with PDD (16 males, 7 females, age range 9-24 years, mean age 15.1±3.9 years) diagnosed according to DSM-IV criteria and followed up for 14.9±8.4 weeks after switching to aripiprazole from risperidone. Outcome measures were the Clinical Global Impression-Severity (CGI-S) and CGI Improvement (CGI-I) scales. The mean CGI-S scores of pre-aripiprazole treatment and post-aripiprazole treatment were, respectively 4.7±1.4 and 4.6±1.3. Mean maintenance dosages of risperidone and aripiprazole were, respectively, 0.7±0.5mg/day and 2.8±1.3mg/day. The mean CGI-I score, which shows the difference induced by switching from risperidone to aripiprazole, was 3.4±0.8 for the whole sample, suggesting that the efficacy of risperidone for treating behavioral problems of PDD was maintained by aripiprazole. Some improvement of safety/tolerability issues such as increased appetite, somnolence, hyperprolactinemia, and amenorrhea occurred after switching to aripiprazole. Results show that switching to aripiprazole might be generally well tolerated and might constitute an alternative treatment for subjects with PDD who experience tolerability issues with risperidone treatment. Additional long-term controlled studies of PDD subjects should be undertaken to evaluate the efficacy and safety of switching to aripiprazole from other antipsychotics.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 04/2012; 37(1):128-31. · 3.55 Impact Factor
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    ABSTRACT: Persons with autism spectrum disorders (ASD) are known to have difficulty in eye contact (EC). This may make it difficult for their partners during face to face communication with them. To elucidate the neural substrates of live inter-subject interaction of ASD patients and normal subjects, we conducted hyper-scanning functional MRI with 21 subjects with autistic spectrum disorder (ASD) paired with typically-developed (normal) subjects, and with 19 pairs of normal subjects as a control. Baseline EC was maintained while subjects performed real-time joint-attention task. The task-related effects were modeled out, and inter-individual correlation analysis was performed on the residual time-course data. ASD-Normal pairs were less accurate at detecting gaze direction than Normal-Normal pairs. Performance was impaired both in ASD subjects and in their normal partners. The left occipital pole (OP) activation by gaze processing was reduced in ASD subjects, suggesting that deterioration of eye-cue detection in ASD is related to impairment of early visual processing of gaze. On the other hand, their normal partners showed greater activity in the bilateral occipital cortex and the right prefrontal area, indicating a compensatory workload. Inter-brain coherence in the right IFG that was observed in the Normal-Normal pairs (Saito et al., 2010) during EC diminished in ASD-Normal pairs. Intra-brain functional connectivity between the right IFG and right superior temporal sulcus (STS) in normal subjects paired with ASD subjects was reduced compared with in Normal-Normal pairs. This functional connectivity was positively correlated with performance of the normal partners on the eye-cue detection. Considering the integrative role of the right STS in gaze processing, inter-subject synchronization during EC may be a prerequisite for eye cue detection by the normal partner.
    Frontiers in Human Neuroscience 01/2012; 6:268. · 2.91 Impact Factor
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    ABSTRACT: Recent human studies have indicated that adverse parenting experiences during childhood and adolescence are associated with adulthood hypothalamus-pituitary-adrenal (HPA) axis hypoactivity. Chronic HPA axis hypoactivity inhibits hippocampal gray matter (GM) development, as shown by animal studies. However, associations among adverse parenting experiences during childhood and adolescence, HPA axis activity, and brain development, particularly hippocampal development, are insufficiently investigated in humans. In this voxel-based structural magnetic resonance imaging study, using a cross-sectional design, we examined the associations among the scores of parental bonding instrument (PBI; a self-report scale to rate the attitudes of parents during the first 16 years), cortisol response determined by the dexamethasone/corticotropin-releasing hormone test, and regional or total hippocampal GM volume in forty healthy young adults with the following features: aged between 18 and 35 years, no cortisol hypersecretion in response to the dexamethasone test, no history of traumatic events, or no past or current conditions of significant medical illness or neuropsychiatric disorders. As a result, parental overprotection scores significantly negatively correlated with cortisol response. Additionally, a significant positive association was found between cortisol response and total or regional hippocampal GM volume. No significant association was observed between PBI scores and total or regional hippocampal GM volume. In conclusion, statistical associations were found between parental overprotection during childhood and adolescence and adulthood HPA axis hypoactivity, and between HPA axis hypoactivity and hippocampal GM volume reduction in healthy young adults, but no significant relationship was observed between any PBI scores and adulthood hippocampal GM volume.
    Human Brain Mapping 12/2011; 33(9):2211-23. · 6.88 Impact Factor
  • Psychiatry and Clinical Neurosciences 10/2011; 65(6):607. · 2.04 Impact Factor
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    ABSTRACT: Individuals with autism spectrum disorders (ASD) show impaired emotional responses to self-face processing, but the underlying neural bases are unclear. Using functional magnetic resonance imaging, we investigated brain activity when 15 individuals with high-functioning ASD and 15 controls rated the photogenicity of self-face images and photographs of others' faces. Controls showed a strong correlation between photogenicity ratings and extent of embarrassment evoked by self-face images; this correlation was weaker among ASD individuals, indicating a decoupling between the cognitive evaluation of self-face images and emotional responses. Individuals with ASD demonstrated relatively low self-related activity in the posterior cingulate cortex (PCC), which was related to specific autistic traits. There were significant group differences in the modulation of activity by embarrassment ratings in the right insular (IC) and lateral orbitofrontal cortices. Task-related activity in the right IC was lower in the ASD group. The reduced activity in the right IC for self-face images was associated with weak coupling between cognitive evaluation and emotional responses to self-face images. The PCC is responsible for self-referential processing, and the IC plays a role in emotional experience. Dysfunction in these areas could contribute to the lack of self-conscious behaviors in response to self-reflection in ASD individuals.
    Social neuroscience 09/2011; · 3.17 Impact Factor
  • Journal of clinical psychopharmacology 06/2011; 31(3):400-1; author reply 401. · 5.09 Impact Factor
  • Journal of clinical psychopharmacology 04/2011; 31(2):243-5. · 5.09 Impact Factor
  • Neuroscience Research - NEUROSCI RES. 01/2011; 71.
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    ABSTRACT: Much functional neuroimaging evidence indicates that autistic spectrum disorders (ASD) demonstrate marked brain abnormalities in face processing. Most of these findings were obtained from studies using tasks related to whole faces. However, individuals with ASD tend to rely more on individual parts of the face for identification than on the overall configuration. Therefore, this neuroimaging evidence might reflect differential visual attention systems in face recognition. It was hypothesized that differential brain function is shown between ASD and control participants with face recognition tasks presenting parts of faces separately. Nine adults with high-functioning ASD and 24 age-matched normal comparison participants were studied using a 3T-MR scanner. We investigated brain activation when processing whole faces and parts of faces displaying positive or negative expressions. The control group showed bilateral amygdalae activation to the whole face, but not to parts of the face. The ASD group showed bilateral amygdalae activation to the lower face (mainly mouth region), but not to the whole face and upper face (mainly eye region). These findings suggest that differential amygdala function for face processing exists in ASD. This aberrant amygdala function might cause abnormalities in gaze processing or recognition of emotional expressions, shown clinically in ASD.
    Research in Autism Spectrum Disorders - RES AUTISM SPECTR DISORD. 01/2011; 5(2):910-919.
  • Neuroscience Research - NEUROSCI RES. 01/2011; 71.
  • Neuroscience Research - NEUROSCI RES. 01/2011; 71.
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    ABSTRACT: Although rapid cycling (RC), a course specifier of bipolar I or II disorder, is particularly common among bipolar II patients compared with bipolar I patients, the pathophysiological lines of evidence regarding bipolar II with RC are still limited. In this preliminary study with a cross-sectional design, we examined the regional gray matter (GM) volume in 14 bipolar II patients with RC, 17 patients without RC and 84 healthy controls by whole-brain and region-of-interest (ROI) analysis methods, using magnetic resonance imaging with voxel-based morphometry. Whole-brain analysis in this study revealed that the bipolar II patients with RC showed GM volume reductions in the bilateral hemispheres of the medial orbital prefrontal cortex, ventromedial prefrontal cortex, anterior cingulate, insula and parahippocampus, in the left hemisphere of the inferior temporal cortex and cerebellum, and in the brainstem, compared with the healthy controls. Moreover, ROI analysis focusing on the ventral prefrontal cortex, i.e., Brodmann areas 10, 11 and 47, revealed that the bipolar II patients with RC showed GM volume reduction in the ventromedial prefrontal cortex, compared with the patients without RC. The findings of our pilot study suggest that the ventromedial prefrontal cortex is associated with the generation of RC in bipolar II disorder.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 11/2010; 35(2):439-45. · 3.55 Impact Factor
  • Progress in Neuro-Psychopharmacology and Biological Psychiatry 10/2010; 34(7):1361-2. · 3.55 Impact Factor
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    ABSTRACT: Enlarged head circumference and increased brain weight have been reported in infants with pervasive developmental disorders (PDD), and volumetric studies suggest that children with PDD have abnormally enlarged brain volumes. However, little is known about brain volume abnormalities in young adults with PDD. We explored gray matter (GM) volume in young adults with PDD. T1-weighted volumetric images were acquired with a 3-T magnetic resonance scanner from 32 males with high-functioning PDD (23.8+/-4.2 years; Full Scale Intelligence Quotient [FSIQ]=101.6+/-15.6) and 40 age-matched normal male control subjects (22.5+/-4.3 years; FSIQ=109.7+/-7.9). Regional GM volumes were compared between the two groups using voxel-based morphometry (VBM) with the Diffeomorphic Anatomical Registration using Exponentiated Lie algebra (DARTEL). Compared with the control group, the high-functioning PDD group showed significantly less GM in the right insula, the right inferior frontal gyrus, and the right inferior parietal lobule. A conservative threshold confirmed considerably smaller volumes in the right insula and inferior frontal gyrus. In these areas, negative correlations were found between Autism Spectrum Quotient scores and GM volume, although no significant correlations were found between each subject's FSIQ and GM volume. No regions showed greater GM volumes in the high-functioning PDD group. The insular cortex, which works as a relay area for multiple neurocognitive systems, may be one of the key regions underlying the complex clinical features of PDD. These smaller GM volumes in high-functioning PDD subjects may reflect the clinical features of PDD itself, rather than FSIQ.
    NeuroImage 05/2010; 50(4):1357-63. · 6.25 Impact Factor
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    ABSTRACT: Previous epidemiologic studies using the parental bonding instrument (PBI), a self-report scale to rate attitudes of parents during the first 16 years, have suggested that a lower parental care score or higher parental overprotection score could lead to an increased risk of several psychiatric disorders, including schizophrenia and mood disorder. However, neuroimaging studies of an association between PBI scores and brain developmental abnormalities are still limited. In this region-of-interest analysis study using a cross-sectional design, we examined 50 normal young adults, in terms of relationships of parental bonding styles during the first 16 years measured by PBI with regional gray matter (GM) volume in the dorsolateral prefrontal cortex (DLPFC). Our study showed that paternal care score positively correlated with the GM volume in the left DLPFC, and paternal and maternal overprotection score negatively correlated with the GM volume in the left DLPFC. In conclusion, our results suggest that in normal young adults, lower paternal care and higher parental overprotection scores correlated with the GM volume reduction in the DLPFC.
    Progress in Neuro-Psychopharmacology and Biological Psychiatry 02/2010; 34(4):624-31. · 3.55 Impact Factor

Publication Stats

714 Citations
159.69 Total Impact Points


  • 2004–2014
    • University of Fukui
      • Division of Neuropsychiatry
      Hukui, Fukui, Japan
  • 2010–2012
    • The Graduate University for Advanced Studies
      • Division of Cerebral Integration
      Миура, Kanagawa, Japan
  • 2011
    • Kyoto University
      • Graduate School of Letters / Faculty of Letters
      Kyoto, Kyoto-fu, Japan
  • 2010–2011
    • Gunma University
      Maebashi, Gunma Prefecture, Japan
  • 2001–2003
    • Fukui University
      Hukui, Fukui, Japan
    • Kinki University
      Ōsaka, Ōsaka, Japan