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Hidehisa Yamashita

Publications and source records attributed to Hidehisa Yamashita.

14 recordsLinked to original sources
PubMed2006

Post-stroke affective or apathetic depression and lesion location: left frontal lobe and bilateral basal ganglia.

This study was designed to examine the correlation between damage to the basal ganglia or frontal lobe and depression status (both affective and apathetic dimensions) in 243 stroke patients. We assessed the affective dimension in post-stroke depression (PSD) using the Zung Self-rating Depression Scale (SDS) and the apathetic dimension in PSD using the apathy scale (AS). We classified basal ganglia or frontal lobe damage into four groups: no damage, damage to the left side only, damage to the right side only, and damage to both sides. Affective and/or apathetic PSD was found in 126 patients (51.9%). The severity of affective depression (SDS score) was associated with left frontal lobe (but not basal ganglia) damage, and that of apathetic depression (AS score) was related to damage to the bilateral basal ganglia (but not to the frontal lobe). The anatomical correlates of PSD differ depending on the PSD dimension (affective or apathetic) and may explain interstudy differences regarding the association between lesion location and type of PSD.

Aged↗
PubMed2006

Anticipation of affective image modulates visual evoked magnetic fields (VEF).

We investigated the interaction between anticipation of positive and negative affective images and visual evoked magnetic fields (VEF). Participants (n = 13) were presented emotionally positive or negative images under different anticipatory conditions, and their subsequent brain responses were recorded by magnetoencephalography (MEG). In the Affective Cue conditions, the cue stimulus indicated the emotional valence of the image, which followed 2 s later. In the Null Cue conditions, the cue stimulus did not include any information about the valence of the image. In the No Cue conditions, the affective image was suddenly presented, without a cue stimulus. The VEF amplitude for the negative image in the Affective Cue condition was smaller than that of the positive image in the Affective Cue condition and that of the negative image in the Null Cue condition. This result suggests that anticipation of the valence of affective images modulates the processes of the visual cortex.

Adult↗
PubMed2005

Distorted images of one's own body activates the prefrontal cortex and limbic/paralimbic system in young women: a functional magnetic resonance imaging study.

BACKGROUND: Our aim was to study the gender differences in brain activation upon viewing visual stimuli of distorted images of one's own body. METHODS: We performed functional magnetic resonance imaging on 11 healthy young men and 11 healthy young women using the "body image tasks" which consisted of fat, real, and thin shapes of the subject's own body. RESULTS: Comparison of the brain activation upon performing the fat-image task versus real-image task showed significant activation of the bilateral prefrontal cortex and left parahippocampal area including the amygdala in the women, and significant activation of the right occipital lobe including the primary and secondary visual cortices in the men. Comparison of brain activation upon performing the thin-image task versus real-image task showed significant activation of the left prefrontal cortex, left limbic area including the cingulate gyrus and paralimbic area including the insula in women, and significant activation of the occipital lobe including the left primary and secondary visual cortices in men. CONCLUSIONS: These results suggest that women tend to perceive distorted images of their own bodies by complex cognitive processing of emotion, whereas men tend to perceive distorted images of their own bodies by object visual processing and spatial visual processing.

Adult↗
PubMed2005

Effects of alcohol on spontaneous neuronal oscillations: a combined magnetoencephalography and electroencephalography study.

Electroencephalography (EEG) and magnetoencephalography (MEG) can detect different aspects of alcohol effects on auditory processing measured with event-related potentials and magnetic fields. The present study aimed to detect alcohol-induced changes in spontaneous neuronal oscillations with combined EEG and MEG techniques. The effects of alcohol on spontaneous neuronal rhythms were studied in 12 healthy subjects after 0.8 g/kg alcohol or juice in a double-blind, placebo-controlled, cross-over design using simultaneous high-resolution MEG and EEG in eyes-open and eyes-closed conditions. The data were analyzed with a power spectral density analysis. MEG recording showed that alcohol significantly increased the relative power of alpha rhythm (8-10 Hz) and reduced the relative power of beta activity (17-25 Hz) in both left and right hemispheres, but only in the eyes-closed condition. These effects did not depend on gender. No analogous statistically significant changes were observed in EEG rhythms. However, the power of alpha and beta rhythms was positively correlated in MEG and EEG recordings, indicating that MEG and EEG reflect similar processes. A distinct sensitivity of MEG and EEG to the sources of cortical oscillations, a better signal-to-noise ratio of MEG, as well as strong spatial blurring of potentials in EEG are most likely the reasons for the observed differences in the effects of alcohol on spontaneous oscillations as detected with two methods.

Adult↗
PubMed2005

Influence of aging on the improvement of subjective sleep quality by atypical antipsychotic drugs in patients with schizophrenia: comparison of middle-aged and older adults.

OBJECTIVE: The authors investigated the influence of aging on the improvement of subjective sleep quality by atypical antipsychotic drugs in patients with schizophrenia. METHODS: Subjects were 86 inpatients (mean age: 61.4 years) who had been receiving treatment with conventional antipsychotic drugs and who met DSM-IV criteria for schizophrenia. Their antipsychotic medication was changed from conventional antipsychotics to one of four atypical antipsychotic drugs (olanzapine, perospirone, quetiapine, or risperidone). Patients were grouped by age (older or younger than 65 years). Subjective sleep quality and psychopathology were assessed twice: 1) at baseline, and 2) 8 weeks after switching to the atypical antipsychotic drugs. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI), and the Positive and Negative Syndrome Scale (PANSS) was used to measure psychopathology. RESULTS: The proportion of the patients who experienced improved subjective sleep quality was significantly higher in the elderly than in the middle-aged group. Logistic-regression analysis revealed that the improvement in subjective sleep quality through administration of atypical antipsychotic drugs was predicted by increased age, daytime dysfunction, and longer sleep latency at baseline. CONCLUSION: These results demonstrate that atypical antipsychotic drugs are beneficial to the quality of sleep in elderly patients with schizophrenia.

Adult↗
PubMed2004

Visual emotional stimuli modulation of auditory sensory gating studied by magnetic P50 suppression.

The auditory sensory gating system modulates its sensitivity to incoming stimuli and prevents higher brain functions from sensory overload in the primary auditory cortex. We investigated whether visually evoked emotional stimuli affect auditory sensory gating. Magnetic P50 (P50m) suppression was evaluated by magnetoencephalography in fifteen healthy subjects while they viewed slides varying in emotional valence and arousal. The ratio of strength of dipole moments of the 2nd to the 1st P50m and the anatomical location of their sources were calculated. Negatively valenced slides significantly attenuated P50m suppression, as compared to neutral ones, while the effects of positive slides were insignificant. No effects on latencies or the location of P50m sources were observed. Thus, negative emotional stimuli may modulate sensory gating.

Adult↗
PubMed2004

Alcohol impairs auditory processing of frequency changes and novel sounds: a combined MEG and EEG study.

RATIONALE: Alcohol has been shown to impair involuntary attention studied by event-related potentials using mismatch negativity (MMN) and P3a. OBJECTIVES: However, no studies have investigated whether alcohol affects the magnetic counterparts of N1 (N1m), MMN (MMNm) and P3a (P3am). METHODS: Auditory evoked potentials and magnetic fields elicited by infrequent deviant tones differing in frequency (5% and 20% change) and novel sounds were recorded with whole-head magnetoencephalography (MEG) and electroencephalography (EEG). Stimuli were presented separately to the left and right ear. Eleven right-handed subjects were studied in a double-blind, placebo-controlled (0.8 g/kg ethanol or juice), cross-over design. N1m, MMNm, and P3am were calculated from the channel pair at the temporal cortex showing the strongest responses in the hemisphere contralateral to the stimulation. N1, MMN and P3a were analyzed from 12 electrodes at the midline frontocentral area. RESULTS: Alcohol reduced bilaterally N1, N1m, MMN and MMNm amplitudes. P3a amplitudes, but not P3am amplitudes were also significantly decreased. No effects of alcohol on the latencies of N1, MMN and P3a or their magnetic counterparts were observed. CONCLUSIONS: Alcohol impairs the processing of tones, frequency change and novel sounds at different phases of auditory processing similarly in both hemispheres. MEG provides us with additional information unobtainable with EEG about the effects of alcohol on the neural correlates of cognition.

Acoustic Stimulation↗
PubMed2004

Effect of switching to atypical antipsychotics on memory in patients with chronic schizophrenia.

While the usefulness of atypical antipsychotics for improving cognitive function has been proven, the specific effects of these drugs are still unknown. The objective of this study was to investigate changes of the immediate memory and verbal working memory in patients with chronic schizophrenia after switching to one of four atypical antipsychotic agents and cessation of anticholinergic therapy. The subjects included 77 schizophrenic patients who were treated primarily with typical antipsychotics. Treatment was randomly switched to one of four atypical antipsychotics (olanzapine, perospirone, quetiapine, or risperidone) over a 4-week period, and then the drug was continued for another 4 weeks while the patient was taken off anticholinergics. The immediate memory, verbal working memory, and symptoms were evaluated. Significant improvement of immediate memory was only seen with olanzapine and risperidone. Improvement was also seen after switching to perospirone, but immediate memory worsened after treatment with this anticholinergic drug was discontinued. Deterioration was seen after switching to quetiapine, but immediate memory improved and reached the previous level after treatment with anticholinergic drugs was discontinued. Significant improvement of the verbal working memory was only seen during risperidone administration. The findings suggested that switching chronic schizophrenic patients to atypical antipsychotics can improve both the immediate memory and the verbal working memory when risperidone is used, while improvement of immediate memory can be expected with olanzapine. From the viewpoint of improving the memory, quetiapine should not be administered concomitantly with anticholinergic drugs, and caution should be exercised when discontinuing anticholinergic drugs during treatment with perospirone.

Acetylcholine↗
PubMed2004

Quetiapine treatment for behavioral and psychological symptoms in patients with senile dementia of Alzheimer type.

The purpose of this study was to assess the effect of quetiapine in the treatment of behavioral and psychological symptoms of dementia (BPSD) in patients with senile dementia of Alzheimer type (SDAT). Sixteen SDAT patients with BPSD were recruited and quetiapine (25- 200 mg/day) was prescribed for 8 weeks. BPSD were evaluated with the Behavioral Pathology in Alzheimer's Disease Rating Scale (BEHAVE-AD) and Cohen-Mansfield Agitation Inventory (CMAI) at week 0 (baseline) and week 8 (endpoint). The severity of the extrapyramidal symptoms was also assessed by the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS) at baseline and endpoint. Significant improvements were seen in the CMAI total score and in the BEHAVE-AD subscales of delusions, activity disturbances, aggressiveness, diurnal rhythm disturbances and in the BEHAVE-AD overall severity. There was no significant difference between the baseline and endpoint in the DIEPSS score. These data indicate that quetiapine is effective in controlling BPSD with favorable adverse-event profiles.

Aged↗
PubMed2004

Effects of changing from typical to atypical antipsychotic drugs on subjective sleep quality in patients with schizophrenia in a Japanese population.

OBJECTIVE: To investigate the effects of the atypical antipsychotic drugs risperidone, olanzapine, quetiapine, and perospirone on the subjective quality of sleep in patients with schizophrenia. METHOD: Subjects were 92 inpatients (mean age = 59.9 years) who had been receiving treatment with conventional antipsychotic drugs and who met the DSM-IV criteria for schizophrenia. Subjects were randomly assigned to receive 1 of 4 atypical antipsychotic drugs (olanzapine, perospirone, quetiapine, and risperidone). Subjective sleep quality and psychopathology were assessed twice: at baseline and 8 weeks after switching. Data were collected from June 2001 to December 2001. Subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI), and psychopathology was measured by the Positive and Negative Syndrome Scale (PANSS). RESULTS: Subjective sleep quality as assessed by the PSQI was significantly improved with administration of olanzapine, risperidone, or quetiapine, but not with perospirone, in comparison with conventional antipsychotic drugs. Multiple regression analysis revealed that the improvement of sleep quality with administration of atypical antipsychotic drugs was predicted by poor sleep quality at baseline. In addition, improvement of sleep quality was significantly correlated with improvement of negative symptoms as assessed by the PANSS. CONCLUSION: These results demonstrated that atypical antipsychotic drugs improved subjective quality of sleep in patients with schizophrenia compared with conventional antipsychotic drugs, suggesting that the marked potency of serotonin-2 receptor blockade in atypical antipsychotic drugs may be involved in the mechanism of this improvement. These improvements were correlated with improvement of negative symptoms.

Adult↗
PubMed2003

Brain activity during expectancy of emotional stimuli: an fMRI study.

We studied the neural activation associated with the expectancy of emotional stimuli using whole brain fMRI. Fifteen healthy subjects underwent fMRI scanning during which they performed a warned reaction task using emotional pictures carrying pleasant, unpleasant, or neutral content. The task involved an expected or unexpected condition. Data were analyzed by comparing the images acquired under the different conditions. In the expected condition, compared with the unexpected condition, significant activation was observed in the medial, inferior and dorsolateral prefrontal cortex. Whereas the expectancy of pleasant stimuli produced activation in the left dorsolateral and left medial prefrontal cortex as well as in the right cerebellum, the expectancy of unpleasant stimuli produced activation in the right inferior and right medial prefrontal cortex, the right amygdala, the left anterior cingulate cortex, and bilaterally in the visual cortex. These results suggest that the expectancy of emotional stimuli is mediated by the prefrontal area including the medial, inferior, and dorsolateral prefrontal cortex. Furthermore, our data suggest that left frontal activation is associated with the expectancy of pleasant stimuli and that right frontal activation is associated with the expectancy of unpleasant stimuli. Finally, our findings suggest that the amygdala and anterior cingulate cortex may play an important role in the expectancy of unpleasant stimuli and that the input of this negative information is modulated by these specific brain areas.

Adult↗
PubMed2002

Effect of risperidone on sleep in schizophrenia: a comparison with haloperidol.

The aim of the present study is to determine the effect of the atypical antipsychotic drug, risperidone on sleep measures in patients with schizophrenia by polysomnography. Sleep measures were compared in five schizophrenic patients who were receiving risperidone alone and five schizophrenic patients who were receiving haloperidol alone. There were no differences between these two groups in their demographic characteristics or doses of antipsychotic medication. The slow wave sleep period was significantly longer in the risperidone-treated group than in the haloperidol-treated group. There were, however, no other significant differences in sleep variables between these groups. This difference in the effect on sleep between risperidone and haloperidol may be due to their differential actions on serotonin (5-HT2) receptors. Risperidone, which is known to be a serotonin-dopamine antagonist, has the potential to improve the quality of sleep in schizophrenic patients.

Adult↗