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ABSTRACT: Seroprevalence surveys of healthcare workers for vaccine-preventable diseases, including measles and varicella, are essential for disease prevention and infection control programmes. The purpose of this study was to compare the complement fixation (CF) assay and an enzyme immunoassay (EIA) to determine the prevalence of immunoglobulin G antibodies directed against measles and varicella viruses in healthcare workers.
Antimeasles and antivaricella antibody titres were measured simultaneously in serum samples from healthcare workers employed at a Japanese university hospital, using the CF assay and an EIA.
Serum samples were obtained from 898 healthcare workers. Seropositivity rates determined using the CF assay and EIA were 67.8% versus 94.0%, respectively, for measles, and 83.2% versus 97.6% for varicella. Compared with EIA, a nine- and 22-fold higher number of seronegative subjects was identified by the CF assay for measles and varicella, respectively.
Differences between the CF assay and EIA in detecting seronegative or seropositive healthcare workers for measles and varicella suggest that undertaking a seroprevalence survey using an EIA, rather than a CF assay, would more accurately determine susceptibility to vaccine-preventable diseases, in healthcare settings.
The Journal of international medical research 02/2013; 41(1):224-30. · 0.90 Impact Factor
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ABSTRACT: Cognitive behavioral therapy (CBT), an effective treatment for depression, targets self-referential processing of emotional stimuli. We examined the effects of CBT on brain functioning during self-referential processing in depressive patients using functional magnetic resonance imaging (fMRI). Depressive patients (n=23) and healthy participants (n=15) underwent fMRI scans during a self-referential task using emotional trait words. The depressive patients had fMRI scans before and after completing a total of 12 weekly sessions of group CBT for depression, whereas the healthy participants underwent fMRI scans 12 weeks apart with no intervention. Before undergoing CBT, the depressive patients showed hyperactivity in the medial prefrontal cortex (MPFC) during self-referential processing of negative words. Following CBT, MPFC and ventral anterior cingulate cortex (vACC) activity during self-referential processing among depressive patients was increased for positive stimuli while it was decreased for negative stimuli. Improvements in depressive symptoms were negatively correlated with vACC activity during self-referential processing of negative stimuli. These results suggest that CBT-related improvements in depressive symptoms are associated with changes in MPFC and vACC activation during self-referential processing of emotional stimuli.
Social Cognitive and Affective Neuroscience 01/2013; · 6.13 Impact Factor
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Keiichi Onoda,
Tsuyoshi Hamano,
Yoko Nabika,
Atsuo Aoyama,
Hiroyuki Takayoshi,
Tomonori Nakagawa,
Masaki Ishihara,
Shingo Mitaki,
Takuya Yamaguchi,
Hiroaki Oguro,
Kuninori Shiwaku,
Shuhei Yamaguchi
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ABSTRACT: We have developed a new screening test for dementia that runs on an iPad and can be used for mass screening, known as the Cognitive Assessment for Dementia, iPad version (CADi). The CADi consists of items involving immediate recognition memory for three words, semantic memory, categorization of six objects, subtraction, backward repetition of digits, cube rotation, pyramid rotation, trail making A, trail making B, and delayed recognition memory for three words. The present study examined the reliability and validity of the CADi.
CADi evaluations were conducted for patients with dementia, healthy subjects selected from a brain checkup system, and community-dwelling elderly people participating in health checkups.
CADi scores were lower for dementia patients than for healthy elderly individuals and correlated significantly with Mini-Mental State Examination scores. Cronbach's alpha values for the CADi were acceptable (over 0.7), and test-retest reliability was confirmed via a significant correlation between scores separated by a one-year interval.
These results suggest that the CADi is a useful tool for mass screening of dementia in Japanese populations.
Clinical Interventions in Aging 01/2013; 8:353-60. · 2.08 Impact Factor
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ABSTRACT: OBJECTIVES:: Our goal was to localize lesions in poststroke depression patients using magnetic resonance imaging, based on the statistical parametric maps image analysis technique that can be used to combine image data from multiple participants and correlate these images with other data sets. METHODS:: Magnetic resonance imaging acquisitions were obtained from 149 poststroke patients, who were assessed for affective and apathetic symptoms using the Hospital Anxiety and Depression Scale and the Apathy Scale, respectively. We created a statistical parametric map that displayed an association between lesion location and affective and apathetic symptoms. RESULTS:: Among the patients with higher depressive scores, the lesion overlap centered on the brainstem, left basal ganglia, and left frontal cortex. Among the patients with higher apathy scores, the lesion overlap centered on the brainstem and bilateral striatum. The overlap lesion for both affective and apathetic depression centered mainly on the brainstem; however, the two types of depression often did not overlap. CONCLUSIONS:: Two core symptoms that can occur after stroke, affective and apathetic symptoms, appear to be associated with different monoaminergic neuroanatomic pathways (serotonergic and dopaminergic).
The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 10/2012; · 3.35 Impact Factor
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ABSTRACT: Functional magnetic resonance imaging (fMRI) was used to investigate brain activation associated with a facial expression identification task (stimuli were full emotional, half emotional, or ambiguous in both happy and sad context) in 10 men and 10 women, fMRI assessment revealed significant interaction of sex x context in the right putamen for the ambiguous faces. Women showed a greater BOLD response to ambiguous facial expression in the sad context than in the happy context, while men showed a greater response in the happy context. Further, women showed a greater BOLD response than did men to ambiguous facial expression in the sad context, while men showed a greater response than women in the happy context. These results suggest that sad and happy context differentially modulate right putamen activation related to processing of ambiguous facial expression in men and women.
Perceptual and Motor Skills 10/2012; 115(2):349-59. · 0.49 Impact Factor
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ABSTRACT: Aging is related to cognitive decline, and it has been reported that aging disrupts some resting state brain networks. However, most studies have focused on the default mode network and ignored other resting state networks. In this study, we measured resting state activity using fMRI and explored whether cognitive decline with aging is related to disrupted resting state networks. Independent component analysis was used to evaluate functional connectivity. Notably, the connectivity within the salience network that consisted of the bilateral insula and the anterior cingulated cortex decreased with aging; the impairment of functional connectivity was correlated with measured decreases in individual cognitive abilities. Furthermore, certain internetwork connectivities (salience to auditory, default mode to visual, etc.) also decreased with aging. These results suggest that (1) aging affects not only the default mode network but also other networks, specifically the salience network; (2) aging affects internetwork connectivity; and (3) disruption of the salience network is related to cognitive decline in elderly people.
Journal of Cognitive Neuroscience 07/2012; 24(11):2186-98. · 5.18 Impact Factor
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ABSTRACT: Depression is characterized by low reward sensitivity in behavioral studies applying signal detection theory. We examined deficits in reward-based decision making in depressed participants during a probabilistic learning task, and used a reinforcement learning model to examine learning parameters during the task.
Thirty-six nonclinical undergraduates completed a probabilistic selection task. Participants were divided into depressed and non-depressed groups based on Center for Epidemiologic Studies-Depression (CES-D) cut scores. We then applied a reinforcement learning model to every participant's behavioral data.
Depressed participants showed a reward-based decision making deficit and higher levels of the learning parameter τ, which modulates variability of action selection, as compared to non-depressed participants. Highly variable action selection is more random and characterized by difficulties with selecting a specific course of action.
These results suggest that depression is characterized by deficits in reward-based decision making as well as high variability in terms of action selection.
Journal of behavior therapy and experimental psychiatry 05/2012; 43(4):1088-94. · 2.48 Impact Factor
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Atsuo Yoshino,
Yasumasa Okamoto, Keiichi Onoda,
Kazuhiro Shishida,
Shinpei Yoshimura,
Yoshihiko Kunisato,
Yoshihiko Demoto,
Go Okada,
Shigeru Toki,
Hidehisa Yamashita,
Shigeto Yamawaki
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ABSTRACT: Pain is a multidimensional phenomenon. Previous psychological studies have shown that a person's subjective pain threshold can change when certain emotions are recognized. We examined this association with magnetoencephalography. Magnetic field strength was recorded with a 306-channel neuromagnetometer while 19 healthy subjects (7 female, 12 male; age range = 20-30 years) experienced pain stimuli in different emotional contexts induced by the presentation of sad, happy, or neutral facial stimuli. Subjects also rated their subjective pain intensity. We hypothesized that pain stimuli were affected by sadness induced by facial recognition. We found: 1) the intensity of subjective pain ratings increased in the sad emotional context compared to the happy and the neutral contexts, and 2) event-related desynchronization of lower beta bands in the right hemisphere after pain stimuli was larger in the sad emotional condition than in the happy emotional condition. Previous studies have shown that event-related desynchronization in these bands could be consistently observed over the primary somatosensory cortex. These findings suggest that sadness can modulate neural responses to pain stimuli, and that brain processing of pain stimuli had already been affected, at the level of the primary somatosensory cortex, which is critical for sensory processing of pain. PERSPECTIVE: We found that subjective pain ratings and cortical beta rhythms after pain stimuli are influenced by the sad emotional context. These results may contribute to understanding the broader relationship between pain and negative emotion.
The journal of pain: official journal of the American Pain Society 04/2012; 13(7):628-35. · 3.78 Impact Factor
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ABSTRACT: Increasing attention has been paid recently to the study of spontaneous brain activity; moreover, particular attention has been paid to the concept of a default-mode network of brain function. Although the functional significance of the default-mode network remains a matter of debate, it has been suggested to be a candidate for the network subserving basic functions related to consciousness. We report the case of a 29-year-old man with encephalopathy and a reversible lesion of the entire corpus callosum. Despite resolution of corpus callosum lesion on magnetic resonance imaging (MRI) within 1 week, the patient persistently presented disturbance of consciousness. Resting-state functional MRI revealed that the posterior cingulate cortex/precuneus was functionally disconnected from other brain regions within the default-mode network. Our case report suggests that assessment of the functional connectivity in the resting-state default-mode network could be a useful marker of consciousness disturbance even in the presence of a reversible brain lesion.
Journal of the neurological sciences 03/2012; 317(1-2):154-6. · 2.32 Impact Factor
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ABSTRACT: Several studies have reported that anorexia nervosa (AN) patients have high levels of alexithymia. However, relatively little is known about the underlying neurobiological relationships between alexithymia and AN. We used functional magnetic resonance imaging to examine the brain responses in 30 AN patients and 20 healthy women during the processing of negative words concerning interpersonal relationships. We investigated the relationship between alexithymia levels and brain activation in AN. AN patients showed significant activation of the orbitofrontal cortex, dorsolateral prefrontal cortex and medial prefrontal cortex while processing negative words concerning interpersonal relationships, as compared to the processing of neutral words. Moreover, the subjective rating of unpleasantness with negative words and neural activities in the amygdala, posterior cingulate cortex (PCC) and anterior cingulate cortex (ACC) negatively correlated with the level of alexithymia in AN. Our neuroimaging results suggest that AN patients tend to cognitively process negative words concerning interpersonal relationships, resulting in activation of the prefrontal cortex. Lower activation of the amygdala, PCC and ACC in response to these words may contribute to the impairments of emotional processing that are hallmarks of alexithymia. Functional abnormalities associated with alexithymia may be involved in the emotional processing impairments in AN patients.
Psychiatry Research 03/2012; 201(2):113-9. · 2.52 Impact Factor
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Frontiers in Neuroscience 01/2012; 6:139.
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Yoshihiko Demoto,
Go Okada,
Yasumasa Okamoto,
Yoshihiko Kunisato,
Shiori Aoyama, Keiichi Onoda,
Ayumi Munakata,
Michio Nomura,
Saori C Tanaka,
Nicolas Schweighofer,
Kenji Doya,
Shigeto Yamawaki
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ABSTRACT: In general, humans tend to discount the value of delayed reward. An increase in the rate of discounting leads to an inability to select a delayed reward over a smaller immediate reward (reward-delay impulsivity). Although deficits in the serotonergic system are implicated in this reward-delay impulsivity, there is individual variation in response to serotonin depletion. The aim of the present study was to investigate whether the effects of serotonin depletion on the ability to evaluate future reward are affected by individual personality traits or brain activation.
Personality traits were assessed using the NEO-Five Factor Inventory and Temperament and Character Inventory. The central serotonergic levels of 16 healthy volunteers were manipulated by dietary tryptophan depletion. Subjects performed a delayed reward choice task that required the continuous estimation of reward value during functional magnetic resonance imaging scanning.
Discounting rates were increased in 9 participants, but were unchanged or decreased in 7 participants in response to tryptophan depletion. Participants whose discounting rate was increased by tryptophan depletion had significantly higher neuroticism and lower self-directedness. Furthermore, tryptophan depletion differentially affected the groups in terms of hemodynamic responses to the value of predicted future reward in the right insula. ConclUSIONS: These results suggest that individuals who have high neuroticism and low self-directedness as personality traits are particularly vulnerable to the effect of low serotonin on future reward evaluation accompanied by altered brain activation patterns.
Neuropsychobiology 01/2012; 65(2):55-64. · 2.67 Impact Factor
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ABSTRACT: People are typically quite sensitive about being accepted or excluded by others. Previous studies have suggested that the dorsal anterior cingulate cortex (dACC) is a key brain region involved in the detection of social exclusion. However, this region has also been shown to be sensitive to non-social expectancy violations. We often expect other people to follow an unwritten rule in which they include us as they would expect to be included, such that social exclusion likely involves some degree of expectancy violation. The present event-related functional magnetic resonance imaging (fMRI) study sought to separate the effects of expectancy violation from those of social exclusion, such that we employed an "overinclusion" condition in which a player was unexpectedly overincluded in the game by the other players. With this modification, we found that the dACC and right ventrolateral prefrontal cortex (rVLPFC) were activated by exclusion, relative to overinclusion. In addition, we identified a negative correlation between exclusion-evoked brain activity and self-rated social pain in the rVLPFC, but not in the dACC. These findings suggest that the rVLPFC is critical for regulating social pain, whereas the dACC plays an important role in the detection of exclusion. The neurobiological basis of social exclusion is different from that of mere expectancy violation.
Frontiers in Evolutionary Neuroscience 01/2012; 4:11.
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ABSTRACT: BACKGROUND: Patients who are unable to eat or drink after stroke may receive percutaneous endoscopic gastrostomy (PEG) or nasogastric tube feeding. Although the most common serious complication is well known to be aspiration pneumonia, the role of gastroesophageal reflux (GER) has not been fully assessed. The aim of this study was to examine, by means of 24-hour esophageal pH monitoring, whether GER is related to aspiration pneumonia and whether the size and laterality of brain lesions influence GER. METHODS: Sixteen stroke patients were examined using a Degitrapper pH400 (Medtronic Japan Co., Tokyo, Japan) and Zinetics 24ME multiuse pH catheter (Medtronic). All patients had stroke lesions in the territory of the left or right middle cerebral artery that were confirmed by magnetic resonance imaging (MRI) and were receiving PEG or nasogastric feeding. Stroke volume was measured with MRIcron software. RESULTS: Nine patients (56%) were diagnosed with GER, and 10 (63%) developed aspiration pneumonia after enteral feeding. The rate of aspiration pneumonia was significantly higher in patients with GER (88.9%) than in those without GER (42.9%; P = .04). Patients with left hemispheric lesions had a significantly higher incidence of acid reflex than those with right lesions (116 ± 105 vs 13 ± 17; P = .04). There were no significant differences in total time of acid reflux or mean pH value between patients with left and right hemispheric lesions. The lesion volume had no significant effect on any of 3 indices of GER. CONCLUSIONS: GER is associated with aspiration pneumonia and occurs more often in patients with stroke lesions in the left hemisphere.
Journal of stroke and cerebrovascular diseases: the official journal of National Stroke Association 08/2011;
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Keiichi Onoda,
Yasumasa Okamoto,
Yoshihiko Kunisato,
Siori Aoyama,
Kazuhiro Shishida,
Go Okada,
Saori C Tanaka,
Nicolas Schweighofer,
Shuhei Yamaguchi,
Kenji Doya,
Shigeto Yamawaki
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ABSTRACT: In general, humans tend to devalue a delayed reward. Such delay discounting is a theoretical and computational concept in which the discount factor influences the time scale of the trade-off between delay of reward and amount of reward. The discount factor relies on the individual's ability to evaluate the future reward. Using functional magnetic resonance imaging, we investigated brain mechanisms for reward valuation at different individual discount factors in a delayed reward choice task. In the task, participants were required to select small/immediate or large/delayed rewards to maximize the total reward over time. The discount factor for each participant individually was calculated from the behavioral data based on an exponential discounting model. The estimated value of a future reward increases as the expected delivery approaches, so the time course of these estimated values was computed based on each individual's discount factor; each was entered into the regression analysis as an explanatory (independent) variable. After the region of interest was narrowed anatomically to the caudate, a peak coordinate was detected in each individual. A correlation analysis revealed that the location of the peak along the dorsal-ventral axis in the right caudate was positively correlated with the discount factor. This implies that individuals who showed a larger discount factor had peak activations in a more dorsal part of the right caudate associated with future reward prediction. This evidence also suggests that a higher ability to delay reward prediction might be related to activation of the more dorsal caudate.
Experimental Brain Research 06/2011; 212(4):593-601. · 2.39 Impact Factor
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ABSTRACT: Recently, neural substrates of the Big Five personality model were investigated using neuroimaging. We examined the relationships between the amplitude of spontaneous low-frequency oscillations (LFO) and the Big Five traits using resting-state functional magnetic resonance imaging (R-fMRI). Twenty-four healthy right-handed undergraduates (23.13±1.87 years, 9 males and 15 females) participated in 5-min R-fMRI and completed the NEO Five-Factor Inventory. We observed that Neuroticism correlated negatively with regional activity of the middle frontal gyrus and precuneus; Extraversion correlated positively with regional activity of the striatum, precuneus, and superior frontal gyrus; Openness correlated positively with the thalamus and amygdala, and negatively with the superior frontal gyrus; Conscientiousness correlated positively with regional activity of the middle frontal gyrus and correlated negatively with the cerebellum. Our results revealed the neural substrates of Extraversion, Neuroticism, Openness, and Conscientiousness in the amplitude of spontaneous LFO.
Neuroscience Letters 02/2011; 492(2):109-13. · 2.11 Impact Factor
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ABSTRACT: In general, emotion is known to enhance memory processes. However, the effect of emotion on associative memory and the underling neural mechanisms remains largely unexplored. In this study, we explored brain activation during an associative memory task that involved the encoding and retrieval of word and face pairs. The word and face pairs consisted of either negative or positive words with neutral faces. Significant hippocampal activation was observed during both encoding and retrieval, regardless of whether the word was negative or positive. Negative and positive emotionality differentially affected the hemodynamic responses to encoding and retrieval in the amygdala, with increased responses during encoding negative word and face pairs. Furthermore, activation of the amygdala during encoding of negative word and neutral face pairs was inversely correlated with subsequent memory retrieval. These findings suggest that activation of the amygdala induced by negative emotion during encoding may disrupt associative memory performance.
PLoS ONE 01/2011; 6(9):e24862. · 4.09 Impact Factor
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ABSTRACT: Recently, resting-state fMRI (R-fMRI) has attracted interest based on its ability to detect the default mode network. We examined the effect of acute tryptophan depletion (ATD) on the fractional amplitude of low-frequency fluctuation (fALFF) during the resting state, and the correlation between changes of mood and fALFF following ATD. We manipulated the central serotonergic levels of 21 right-handed healthy males (mean age=21.57±1.83 years) following ATD. A within-subjects, double-blind, placebo-controlled, and counter-balanced design was employed. Following ATD or sham depletion, subjects completed the Profile of Mood States (POMS) and underwent 5-min R-fMRI scans. Our findings show that the fALFF of the middle orbitofrontal cortex and precuneus was significantly decreased and the fALFF of the superior parietal lobule, paracentral lobule and precentral gyrus was significantly increased after ATD. The fALFF of the orbitofrontal cortex was negatively correlated with depressive mood. The fALFF of the superior parietal lobule was positively correlated with anger-hostility and the fALFF of the paracentral lobule was negatively correlated with vigor-activity. The middle orbitofrontal cortex plays a key role in serotonin depletion-induced brain changes and individual differences in depressive mood change. These results serve to further elucidate the mechanism of ATD-induced relapse in remitted MDD patients.
Neuroscience Research 11/2010; 69(2):129-34. · 2.25 Impact Factor
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ABSTRACT: Although apathy has been reported as one of the neuropsychiatric symptoms following stroke, there are few studies on regional cerebral blood flow (rCBF) in stroke patients with apathy. The present study compared rCBF between apathetic and non-apathetic patients after stroke.
We recruited 102 patients with cerebral infarction within 1 month after stroke and performed neuropsychiatric assessments that included the apathy scale. rCBF was quantitatively measured using N-isopropyl-p-(123)I-iodoamphetamine single-photon emission computed tomography.
Thirty-seven patients (36%) had apathy. The apathetic group showed lower cognitive function and a higher depressive state than the non-apathetic group. rCBF in the basal ganglia was reduced for the apathetic group compared with the non-apathetic group. Furthermore, lesions in the left basal ganglia were associated with hypoperfusion in bilateral basal ganglia and the presence of apathy.
These findings demonstrate that apathy is a frequent symptom among stroke patients and that hypoperfusion caused by basal ganglia lesions may contribute to post-stroke apathy.
Cerebrovascular Diseases 10/2010; 31(1):6-11. · 2.72 Impact Factor
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ABSTRACT: Recent studies of electroencephalogram event-related potentials reported aberrant feedback-related negativity (FRN) in neurological and psychiatric diseases, such as alcoholism and attention-deficit hyperactivity disorder. These diseases are characterized by high impulsivity. We investigated the relationship between FRN and impulsivity in healthy people. We performed correlation analyses between FRN amplitude recorded during a gambling task and Barratt Impulsiveness Scale scores. The analysis showed a significant negative correlation between FRN amplitude and the nonplanning impulsiveness score, which assess lack of past planning or future orientation. This suggests that FRN may be a neurophysiological marker of unplanned impulsiveness.
Neuroreport 07/2010; 21(10):736-9. · 1.66 Impact Factor
