Biomedical subjects

Masato Inoue

Publications and source records attributed to Masato Inoue.

At least 19 recordsLinked to original sources

PubMed2006

Prevalence of typus melancholicus in healthy germans.

BACKGROUND: There have been few studies concerning the prevalence of Typus melancholicus (TM) in healthy volunteers based on age or sex. To our knowledge, no such studies have been performed in healthy Germans, but several in healthy Japanese people. Therefore, it is necessary to also determine the prevalence of TM in healthy Germans, in order to know whether the prevalence of TM is cross-culturally constant. SUBJECTS AND METHODS: We examined the prevalence of TM in 121 healthy German volunteers (62 men and 59 women with a mean age +/- SD of 43.9 +/- 16.8 years and 47.4 +/- 15.9 years, respectively). Kasahara's Inventory for the Melancholic Type Personality (KIMTP) and von Zerssen's F-List (F-List) were used to identify TM. The subjects were divided by age into three groups: those aged 40 years or less (group A), those aged 41-60 years (group B), and those aged 61 years or more (group C). Mean total KIMTP and F-List scores were calculated. In addition, we also calculated mean scores of the two KIMTP TM factors ['harmony in personal relationships' (factor 1) and 'social norms' (factor 2)]. Differences in scores between men and women were analyzed by Student's t test. Differences in scores between the three age groups were evaluated by one-way analysis of variance and Scheffé's test. RESULTS: The KIMTP and F-List scores increased with age in both men and women. In the women, the KIMTP and F-List scores were significantly higher in groups B and C than in group A. In the women, the group C KIMTP factor 1 score was significantly higher than the group A KIMTP factor 1 score. The KIMTP and F-List scores tended to be higher for the women than for the men. Within groups B and C, the KIMTP and F-List scores and the KIMTP factor 1 score were significantly higher for the women than for the men. CONCLUSION: Overall, the sex and age distributions of scores for both questionnaires were similar to those obtained in previous studies in Japanese people. It is of note that our German subjects and previous Japanese subjects were not demographically controlled and, clearly, cultural backgrounds differed. Thus, KIMTP and the F-List may discriminate the TM personality with some degree of universality despite cultural differences and might be useful in cross-cultural comparisons of TM.

Adult↗

PubMed2005

Correspondence of cue activity to reward activity in the macaque orbitofrontal cortex.

It has been reported that neurons in the orbitofrontal cortex (OFC) respond to emotionally significant events such as reward-predicting cues and/or the reward itself. The responses to reward-predicting cues are considered to carry the information of the predicted reward. However, few studies have focused on the relationship of the neuronal activity during a cue period with that during a reward period. We can infer that the cue responses of OFC neurons are correlated to the reward responses if they carry the information of the predicted reward. In this study, we focused on neurons that showed responses during both the cue and reward periods, and compared the response characteristics between these periods. We found 94 of 369 OFC neurons showed significant responses during both the cue and reward periods, and 43 of which preserved their selectivity between these periods. Furthermore, population analysis showed that stronger cue responses corresponded to stronger reward responses, and stronger reward responses corresponded to stronger cue responses. These results suggest that individual neurons in the OFC associate visual information with reward information, and contribute to the prediction of future rewards by forming reward representations.

Animals↗

PubMed2005

Prefrontal activity during serial probe reproduction task: encoding, mnemonic, and retrieval processes.

To study the prefrontal neuronal mechanism for the encoding and mnemonic processing of multiple objects, the order of object presentation, and the retrieval of an object among objects in the working memory, we recorded neuronal activity from the lateral prefrontal cortex while two monkeys performed the serial probe reproduction task. In the task, two objects (C1 and C2) were presented sequentially interleaved with a delay (D1) period, and after the second delay (D2) period, a color cue was presented. Monkeys were trained to select one target object on the basis of the color stimulus. During the C1 and C2 periods, we found responses that depended on the order of presentation (order-selective response). During the D1 and/or D2 periods, two-thirds of the neurons with object-selective delay-period activity showed order-selective activity coding either C1 or C2. Neurons with larger response magnitudes during the C2 period showed order-selective delay-period activity during the D2 period. These order-selective responses during the C2 period could also contribute to order-selective delay-period activity, and order-selective delay-period activity during the D1 and D2 periods could play an essential role in storing information on both the object and the temporal order of presentation. During the color cue period, two-thirds of the neurons with responses showed target object selectivity (CT and T responses), although the target object was not presented during this period. The CT and T responses could play a critical role in the retrieval of an item among various items in the working memory.

Action Potentials↗

PubMed2005

Subjective symptoms among female workers and winter working conditions in a consumer cooperative.

Subjective musculoskeletal symptoms are more frequently complained about in cold store work and in related conditions than in normal temperature work. This cross sectional study was undertaken (a) to explore the prevalence of subjective symptoms in winter among a group of female workers engaged in classification of cold storage goods, and in a group of female checkers in several supermarkets of a large consumer cooperative; and (b) to give recommendations for improving the winter working conditions of these workers. The subjects consisted of 46 workers engaged in classification of cold storage goods, 56 checkers operating a laser scanner in supermarkets and 59 office workers (control group). Work loads for the three groups were estimated according to the recommended criteria. A self-administered questionnaire covering age, occupational career, smoking, alcohol drinking and physical exercise, present or past history of diseases, individual protective measures against cold, and subjective symptoms (54 items) was used. The air temperature of the working site at the opening time for classification workers was 4.8 degrees C which was significantly lower than those measured for the other two work places (12.1 degrees C and 15.8 degrees C). About 70 to 80% of classification workers complained of cold sensation in different body regions, as well as shoulder stiffness, and problems related to the back. The supermarket checkers and office workers had a high prevalence of cold sensation in their feet. The frequencies of using warm clothes and foot heaters, as an individual measure to work comfortably in winter among the classification workers and the checkers were significantly higher than that among the office workers. We concluded that work difficulty due to moderate cold exposure among workers in the consumer cooperative could be reduced by some physical activity as well as proper clothes.

Adult↗

PubMed2005

[Stress management among hospital nurses--stress & stress-coping scale (SSCQ) as applied to nurses].

The purpose of this study was to evaluate the validity of the Stress and Stress-Coping Questionnaire (SSCQ) for female nursing groups. Subjects were 300 female nurses employed at hospitals. Mean age was 32.9 +/- 8.9 yr and mean number of years of work experience was 11.9 +/- 8.0 yr. Data for the study were collected via the self-completed SSCQ, which all subjects completed. In order to asses the validity of the SSCQ, subjects were also asked to complete a 60-question General Health Questionnaire (GHQ) that assessed mental well being. Based on the results of factor analysis, the original version of the SSCQ, comprising 153 questions in 10 subscales, was revised to the nurse-specific SSCQ-N, comprising 123 questions and 15 subscales. Cronbach's alpha coefficient for subscales varied from 0.70 to 0.83, showing a significant correlation with the point score of the GHQ, for demonstrating criterion-related validity in the SSCQ. These results verify the usefulness for female nursing groups of the SSCQ for assessing mental well being and suggesting ways to manage stress in nurses.

Adaptation, Psychological↗

PubMed2004

Neurons in the orbitofrontal cortex code both visual shapes and reward types.

It has been reported that neurons in the orbitofrontal cortex respond to visual cues that predict reward; however, few studies have focused on the neuronal correlates with the predicted reward type and the cue stimulus. In this study, we used a paired association task and introduced a reversal condition, in which cue stimuli that usually predict water were switched to predict juice, and vice versa. Of 111 cue-responsive neurons, 60 neurons (54.1%) depended on both the cue stimulus and the predicted reward type. The results suggest that neurons in the orbitofrontal cortex can code both visual and reward information, and contribute to the association between these two pieces of information according to the current combination of a cue stimulus and a reward type.

Animals↗

PubMed2004

Dynamics of the adaptive natural gradient descent method for soft committee machines.

Adaptive natural gradient descent (ANGD) method realizes natural gradient descent (NGD) without needing to know the input distribution of learning data and reduces the calculation cost from a cubic order to a square order. However, no performance analysis of ANGD has been done. We have developed a statistical-mechanical theory of the simplified version of ANGD dynamics for soft committee machines in on-line learning; this method provides deterministic learning dynamics expressed through a few order parameters, even though ANGD intrinsically holds a large approximated Fisher information matrix. Numerical results obtained using this theory were consistent with those of a simulation, with respect not only to the learning curve but also to the learning failure. Utilizing this method, we numerically evaluated ANGD efficiency and found that ANGD generally performs as well as NGD. We also revealed the key condition affecting the learning plateau in ANGD.

Journal Article↗

PubMed2004

Dimension of Typus melancholicus on Kasahara's Inventory for the Melancholic Type Personality.

BACKGROUND: Traditionally, Typus melancholicus (TM) was considered, a priori, to represent unidimensionality. Recent studies have suggested that TM is not a personality trait, but rather a constellation of personality traits. The purpose of this study was to examine whether TM on Kasahara's Inventory for the Melancholic Type Personality (KIMTP), considered to represent one of the valid TM questionnaires, is comprised of personality dimensions, and if so, which dimension is essential for distinguishing depressive subjects from control subjects. SUBJECTS AND METHODS: To clarify the dimensionality of TM scores on KIMTP, factor analysis of the TM scores was conducted using principal factor analysis followed by varimax rotation. Comparisons were then made between endogenous depressive patients (n = 38), nonendogenous depressive patients (n = 20), and healthy volunteers (n = 81) for total KIMTP score and factor scores using analysis of covariance, adjusting for sex and age. RESULTS: Factor analysis of KIMTP revealed 2 distinct clusters of items, i.e. 'harmony in personal relationships' (factor 1) and 'social norms' (factor 2). Endogenous and nonendogenous depressive patients showed significantly higher KIMTP total and factor 1 scores than did control subjects. However, no significant differences were observed for KIMTP total score and scores of individual factors between endogenous and nonendogenous depressive patients. CONCLUSIONS: The present results indicate that TM on KIMTP represents a constellation of personality traits, and that the factor 'harmony in personal relationship' possesses the essential meaning for assessing TM.

Adult↗

PubMed2004

Functional brain mapping of the macaque related to spatial working memory as revealed by PET.

To define the cortical areas that subserve spatial working memory in a nonhuman primate, we measured regional cerebral blood flow (rCBF) with [(15)O]H(2)O and positron emission tomography while monkeys performed a visually guided saccade (VGS) task and an oculomotor delayed-response (ODR) task. Both Statistical Parametric Mapping and regions of interest-based analyses revealed an increase of rCBF in the area surrounding the principal sulcus (PS), the superior convexity, the anterior bank of the arcuate sulcus (AS), the lateral orbitofrontal cortex (lOFC), the frontal pole (FP), the anterior cingulate cortex (ACC), the lateral bank of the intraparietal sulcus (lIPS) and the prestriate cortex. In the prefrontal cortex (PS, superior convexity, AS, lOFC and FP), rCBF values correlated positively with ODR task performance scores. From the hippocampus, rCBF values correlated negatively with ODR task performance. From the AS, superior convexity, lOFC, FP, ACC and lIPS, rCBF values of the PS correlated positively with rCBF values and negatively with hippocampus rCBF values. These results suggest that neural circuitry in the prefrontal cortex directly contributes the spatial working memory processes and that, in spatial working memory processes, the posterior parietal cortex and hippocampus have a different role to the prefrontal cortex.

Animals↗

PubMed2004

Stimulus duration in working memory is represented by neuronal activity in the monkey prefrontal cortex.

Humans are capable of memorizing several attributes of a presented stimulus as well as its duration of presentation. However, the neuronal representation of stimulus duration in memory remains unknown. This study investigated activities of single neurons in the prefrontal cortex of monkeys while they were performing a behavioral task in which working memory for stimulus duration was needed. Here we describe specific neurons whose discharge rates reflect encoding or retention of the duration of the presentation of stimuli to be remembered. We also describe other specific neurons whose activities reflect encoding or retention of fixed duration, similar but unrelated to the stimulus duration presented in each trial. Some of these specific neurons showed the same duration-related discharges even while the monkeys were performing a different task, in which working memory for stimulus duration was no longer needed. From these results, we suggest that neurons in the prefrontal cortex play roles in encoding and retention of temporal information in working memory and that some of those neurons are dedicated to representation of temporal information attributed to stimuli even when the temporal information is unnecessary for correct performance.

Action Potentials↗

PubMed2004

Improved parameter estimation for variance-stabilizing transformation of gene-expression microarray data.

A gene-expression microarray datum is modeled as an exponential expression signal (log-normal distribution) and additive noise. Variance-stabilizing transformation based on this model is useful for improving the uniformity of variance, which is often assumed for conventional statistical analysis methods. However, the existing method of estimating transformation parameters may not be perfect because of poor management of outliers. By employing an information normalization technique, we have developed an improved parameter estimation method, which enables statistically more straightforward outlier exclusion and works well even in the case of small sample size. Validation of this method with experimental data has suggested that it is superior to the conventional method.

Algorithms↗

PubMed2003

Gene interaction in DNA microarray data is decomposed by information geometric measure.

MOTIVATION: Given the vast amount of gene expression data, it is essential to develop a simple and reliable method of investigating the fine structure of gene interaction. We show how an information geometric measure achieves this. RESULTS: We introduce an information geometric measure of binary random vectors and show how this measure reveals the fine structure of gene interaction. In particular, we propose an iterative procedure by using this measure (called IPIG). The procedure finds higher-order dependencies which may underlie the interaction between two genes of interest. To demonstrate the method, we investigate the interaction between the two genes of interest in the data from human acute lymphoblastic leukemia cells. The method successfully discovered biologically known findings and also selected other genes as hidden causes that constitute the interaction. AVAILABILITY: Softwares are currently not available but are possibly made available in future at http://www.mns.brain.riken.go.jp/~nakahara/DNA_pub.html where all the related information is also linked.

Algorithms↗

PubMed2003

Cortical correlates of vestibulo-ocular reflex modulation: a PET study.

To elucidate cortical correlates of vestibulo-ocular reflex (VOR) modulation, we observed cortical activation during fixation suppression and habituation of caloric vestibular nystagmus in 12 normal subjects, using PET. Significant positive correlation between regional cerebral blood flow (rCBF) and slow phase eye velocity of caloric nystagmus was observed in the middle and posterior insula, inferior parietal lobule, temporal pole, right fusiform gyrus, lingual gyrus, and cerebellar vermis and hemisphere. The rCBF increase in the insular region and the inferior parietal lobule was lateralized depending on the direction of the nystagmus. Caloric nystagmus was suppressed as a result of visual fixation, during which time the area around the right frontal eye field, temporal pole, inferior temporal gyrus, a broad area in the visual cortex, including fusiform and lingual gyrus, cerebellar uvula/nodulus and flocculus, exhibited positive correlation with fixation suppression of caloric nystagmus, while vestibular cortices exhibited negative correlation. The caloric nystagmus habituated with repetition of stimulation. With habituation, we observed activation in the right anterior cingulate gyrus, left superior parietal lobule and right cuneus, and deactivation in the anterior insula, cingulate gyrus, inferior parietal lobule and occipito-temporal visual cortex. The region that showed significant co-activation with fixation suppression and habituation of caloric nystagmus was the right cuneus, and significant co-deactivation was observed in the anterior insula, cingulate gyrus, inferior parietal lobule and middle temporal visual cortex. The present results support previous observations that the parieto-insular cortex and inferior parietal lobule are involved in processing of vestibular information, and, in addition, suggest that activation may depend on the direction of nystagmus. Deactivation of vestibular cortices during visual fixation supports the concept of inhibitory visual-vestibular interaction in the cortex. Significant activation of the cingulate, superior parietal and visual cortices, and cerebellar vermis accompanying reduction of caloric response with repeated stimuli suggests possible involvement of these regions in vestibular habituation. Common activation of the cuneus in visual cortex and deactivation of vestibular and visuo-spatial association cortices by both visual suppression and habituation of VOR suggests that these two mechanisms are not completely independent but may share some cortical and subcortical regions.

Adult↗

PubMed2003

Inner ear hearing loss modulates ipsilateral temporal lobe activation by monaural speech stimuli.

We examined cortical activation by speech in patients with moderate inner ear hearing loss using PET to investigate the response of the language network to insufficient speech input. We made two word lists, well-perceived words and poorly-perceived words, and measured rCBF during monaural presentation of these words. Well-perceived words activated bilateral temporal lobes, bilateral inferior frontal gyri (IFG) and left angular gyrus (AG) regardless of the ear stimulated, Poorly-perceived words activated contralateral temporal lobe and bilateral IFG, while little or no activation was observed in the ipsilateral temporal lobe and left AG. Insufficient activation of the temporal lobe ipsilateral to the ear stimulated might correlated with less accurate word comprehension in patients with inner ear hearing loss.

Acoustic Stimulation↗

PubMed2003

Perception of shape-from-motion in macaque monkeys and humans.

Motion is one of the most efficient cues for shape perception. We conducted behavioral experiments to examine how monkeys perceive shapes defined by motion cues and whether they perceive them as humans do. We trained monkeys to perform a shape discrimination task in which shapes were defined by the motion of random dots. Effects of dot density and dot speed on the shape perception of monkeys were examined. Human subjects were also tested using the same paradigm and the test results were compared with those of monkeys. In both monkeys and humans, correct performance rates declined when density or speed of random dots was reduced. Both of them tended to confuse the same combinations of shapes frequently. These results suggest that monkeys and humans perceive shapes defined by motion cues in a similar manner and probably have common neural mechanisms to perceive them.

Adult↗

PubMed2003

Stimulus-induced behavior in F1 hybrids of seizure-sensitive and seizure-resistant gerbils.

We previously established two strains of Mongolian gerbil: a seizure-sensitive strain, established by selective inbreeding for motor seizures elicited by a stimulus called the S method and a seizure-resistant strain that does not exhibit inducible seizures. The behavior of the seizure-sensitive strain is characterized by a progressive increase in responsiveness to weekly application of the S method, from repetitive backward ear movements appearing after postnatal day 40, to a full-blown seizure, while the seizure-resistant strain is apparently unaffected by the stimulation. The difference between these two strains is presumably genetic. To determine the genetic factors underlying this difference, we first examined developmental changes in the stimulus-induced behavior of the F1 hybrids. When the S method was applied, most F1 hybrids had repetitive movements of the ears (and head) similar to the seizure-sensitive gerbils, but generalized seizures emerged considerably later than in seizure-sensitive gerbils. These results suggest that a half dose of the gene products involved renders most gerbils susceptible to the stimulus but is insufficient for the rapid accumulation of an as yet undefined change needed to spread the abnormal electrophysiologic activity to elicit generalized seizures.

Age Factors↗

PubMed2003

[Uterine artery embolization for leiomyoma: complications and effects on fertility].

Uterine artery embolization (UAE) for leiomyoma is becoming accepted as an alternative to surgical treatment. However, gynecologists who have treated follow-up patients are greatly concerned about the postoperative course after UAE. One significant complication after UAE is infection owing to obstruction resulting from the sloughing of necrotic fibroids that interfere with the passage of intrauterine discharge. In our UAE procedures, the incidence of infection requiring hospitalization was 3.6%, and one patient (0.22%) had to undergo hysterectomy. Transcervical resection (TCR) using hysteroscopy is an extremely effective surgical intervention for removing necrotic fibroids for reserve of the uterus. However, additional treatment for intrauterine abnormalities after UAE may rest on whether or not the hysteroscopic procedure was performed. Although ovarian function after UAE seems to be maintained in patients < or = 44 years of age, serious complications include intrauterine adhesions that appear as amenorrhea or hypomenorrhea and lead to infertility. The results of our hysteroscopic evaluation after UAE in 7 patients who wished to conceive was intrauterine adhesion in four patients, subendometrial liner scar in one patient, and yellowing of the endometrium in three patients. However, in spite of impairment of the endometrium, the pregnancy rate after UAE in our study was 5/10(50.0%). It is essential that the indications of UAE for patients who wish to conceive be decided according to careful individual evaluation, and cautious follow-up is necessary.

Adult↗

PubMed2002

Prefrontal delay-period activity is affected by visual cues presented outside the memory field.

To examine interactions between primate prefrontal neurons having memory fields, we examined whether primate prefrontal delay-period activity produced by a visual cue presented inside the neuron's memory field is affected by an additional visual cue presented inside or outside the memory field in 39 prefrontal neurons. Delay-period activity was either diminished (43%) or enhanced (16%) when an additional cue was presented at a certain area in the visual field. Since functional interactions among neighboring prefrontal neurons were present, these modulation could be caused by the interactions between neurons having memory fields in different positions.

Animals↗