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Toshio Inui

Publications and source records attributed to Toshio Inui.

15 recordsLinked to original sources
PubMed2006

Separating brain regions involved in internally guided and visual feedback control of moving effectors: an event-related fMRI study.

Online visual information of moving effectors plays important roles in visually guided movements. The present study used event-related functional resonance imaging to temporally separate neural activity associated with internally guided and visual feedback control of moving effectors. Using a cursor controlled by a computer mouse, participants traced curved lines on a screen. During this movement, vision of the moving cursor was occluded after tracing had begun and then was restored after variable intervals. The results showed that when visual feedback was unavailable, bilateral activation was significantly greater in the basal ganglia, thalamus, premotor cortex and mesial motor areas, peaking at the presupplementary motor area (pre-SMA). In contrast, when visual feedback was available, significantly greater activation was observed bilaterally in the posterior parietal cortex (PPC) and cerebellum and in the middle and inferior frontal gyri and occipito-temporal cortex in the right hemisphere. Pre-SMA activity was significantly negatively correlated with tracing error when visual feedback was unavailable. In contrast, right PPC activation showed a significant positive correlation with tracing error after visual feedback became available. These findings suggest that the pre-SMA is involved in internally guided movements in the absence of visual feedback, and that the PPC is related to visual feedback control by evaluating online visuomotor error. The current study clarifies the different functional roles of fronto-parietal and cerebellum circuits subserving visually guided movements regarding visual feedback control of effectors.

Adult↗
PubMed2006

The effect of viewing the moving limb and target object during the early phase of movement on the online control of grasping.

Two experiments were conducted to investigate (1) during which phase of the movement vision is most critical for control, and (2) how vision of the target object and the participant's moving limb affect the control of grasping during that movement phase. In Experiment 1, participants, wearing liquid crystal shutter goggles, reached for and grasped a cylinder with a diameter of 4 or 6 cm under a shutting paradigm (SP) and a re-opening paradigm (RP). In SP, the goggles closed (turned opaque) 0 ms, 150 ms, 350 ms, 500 ms, or 700 ms after movement onset, or remained open (transparent) during the prehension movements. In RP, the goggles closed immediately upon movement onset, and re-opened 0 ms (i.e., without initially shutting), 150 ms, 350 ms, 500 ms, or 700 ms after the initial shutting, or remained opaque throughout the prehension movements. The duration of the prehension movements was kept relatively constant across participants and trials at approximately 1100 ms, i.e., the duration of prehension movements typically observed in daily life. The location of the target object was constant during the entire experiment. The SP and RP paradigms were counter-balanced across participants, and the order of conditions within each session was randomized. The main findings were that peak grip aperture (PGA) in the 150 ms-shutting condition was significantly larger than in the 350 ms-shutting condition, and that PGA in the 350 ms-re-opening condition was significantly larger than in the 150 ms-re-opening condition. These results revealed that online vision between 150 ms and 350 ms was critical for grasp control on PGA in typical, daily-life-speeded prehension movements. Furthermore, the results obtained for the time after maximal deceleration (TAMD; movement duration-time to maximal deceleration) demonstrated that early-phase vision contributed to the temporal pattern of the later movement phases (i.e., TAMD). The results thus demonstrated that online vision in the early phase of movement is crucial for the control of grasping. In addition to the apparatus used in Experiment 1, two liquid shutter plates placed in the same horizontal plane (25 cm above the experimental table) were used in Experiment 2 to manipulate the visibility of the target and the participant's moving limb. The plate closest to the participant altered vision of the limb/hand, while the more distant plate controlled vision of the object. The conditions were as follows: (1) both plates were open during movement (full vision condition); (2) both plates were closed 0, 150, or 350 ms following onset of arm movement (front-rear condition: FR); or (3) only the near plate closed 0, 150, or 350 ms following the onset of the arm movement (front condition: F). The results showed that shutting at 0 and 150 ms in the FR condition caused a significantly larger PGA, while the timing of shutting in the F condition had little influence on the PGA. These findings indicated that online vision, especially of the target object, during the early phase of prehension movements is critical to the control of grasping.

Arm↗
PubMed2006

A neurolinguistic model of grammatical construction processing.

One of the functions of everyday human language is to communicate meaning. Thus, when one hears or reads the sentence, "John gave a book to Mary," some aspect of an event concerning the transfer of possession of a book from John to Mary is (hopefully) transmitted. One theoretical approach to language referred to as construction grammar emphasizes this link between sentence structure and meaning in the form of grammatical constructions. The objective of the current research is to (1) outline a functional description of grammatical construction processing based on principles of psycholinguistics, (2) develop a model of how these functions can be implemented in human neurophysiology, and then (3) demonstrate the feasibility of the resulting model in processing languages of typologically diverse natures, that is, English, French, and Japanese. In this context, particular interest will be directed toward the processing of novel compositional structure of relative phrases. The simulation results are discussed in the context of recent neurophysiological studies of language processing.

Brain↗
PubMed2006

[Forgetting properties of orientation information of natural objects].

The purpose of this research was to compare the forgetting property of object orientation information and identity information. They were measured by two types of recognition tests about both of information of natural objects presented in Rapid Serial Visual Presentation (RSVP). Participants were one hundred and twenty undergraduates who were tested with two recognition tests. The results indicated; (1) Short-term memory for orientation information was inferior to that for identity information; (2) Estimated decay rate of orientation information was about twice as fast as that of identity information; (3)Orientation information was forgotten in about two seconds regardless of the category level of presented objects. Finally, the validity of recognition tests of object orientation and the independence of identity information and orientation information are discussed.

Adult↗
PubMed2005

Helicobacter pylori infection is associated with colon adenomatous polyps detected by high-resolution colonoscopy.

Helicobacter pylori (H. pylori) is associated with the development of cancer in the stomach, but both positive and negative associations were reported with colorectal neoplasia. We sought to determine whether H. pylori is associated with colon neoplasia in Japanese population. We examined 332 patients who underwent routine high-resolution total colonoscopy and serologic testing for IgG antibodies agonist H. pylori. Subjects who received cyclooxygenase-2 inhibitors or previous eradication therapy and those with borderline titer levels were excluded from data analysis (n = 27). Seronegative control subjects were from the same study population to maximize the representativeness. There were no significant differences in age and gender between the 2 patient groups. A significant increase in the incidence of adenomatous polyps (p < 0.0001) and decrease in normal colonoscopic findings (p < 0.0005) were observed in seropositive patients than those seronegative. Our study indicates an etiological link of H. pylori infection to colorectal neoplasia and the need of routine colonoscopy in seropositive patients.

Adenomatous Polyps↗
PubMed2003

Neural correlates of semantic effects on grasping familiar objects.

This study used event-related fMRI to explore the neural basis of semantic involvement when performing a visually guided grasping movement. Three types of object images were presented in random order: familiar objects with handles (FH+) familiar objects without handles (FH-) and geometrical objects with a handle-like part (GH+). Subjects were then instructed to configure an appropriate hand shape for grasping the object. Common activations were found for all event types when contrasted with baseline. Activation of the anterior part of the rostral cingulate motor area was detected for only the FH+ condition and these results imply that the appropriate selection of multiple motor schemata took place in this region.

Adult↗
PubMed2003

Facial recognition reactivates the primary visual cortex: an functional magnetic resonance imaging study in humans.

In order to investigate how the brain represents sensory-specific information during memory retrieval, we examined functional magnetic resonance imaging's during a face-recognition task. When compared with activation associated with viewing of novel faces, recognition of faces presented 5 min before scanning activated the primary visual cortex, consistent with the hypothesis that retrieved facial information is coded by the reactivation of the brain regions engaged during sensory perception. This reactivation was not observed 14 weeks following initial presentation of the faces despite no significant difference in recognition rate between the two intervals. This suggests that accessing of visual information during memory retrieval is associated with the primary visual cortex, and that its activation is time-dependent--probably related to the memory transformation or consolidation.

Adult↗
PubMed2003

Spatiochromatic receptive field properties derived from information-theoretic analyses of cone mosaic responses to natural scenes.

Neurons in the early stages of processing in the primate visual system efficiently encode natural scenes. In previous studies of the chromatic properties of natural images, the inputs were sampled on a regular array, with complete color information at every location. However, in the retina cone photoreceptors with different spectral sensitivities are arranged in a mosaic. We used an unsupervised neural network model to analyze the statistical structure of retinal cone mosaic responses to calibrated color natural images. The second-order statistical dependencies derived from the covariance matrix of the sensory signals were removed in the first stage of processing. These decorrelating filters were similar to type I receptive fields in parvo- or konio-cellular LGN in both spatial and chromatic characteristics. In the subsequent stage, the decorrelated signals were linearly transformed to make the output as statistically independent as possible, using independent component analysis. The independent component filters showed luminance selectivity with simple-cell-like receptive fields, or had strong color selectivity with large, often double-opponent, receptive fields, both of which were found in the primary visual cortex (V1). These results show that the "form" and "color" channels of the early visual system can be derived from the statistics of sensory signals.

Humans↗
PubMed2003

Helicobacter pylori cytotoxin: a novel ligand for receptor-like protein tyrosine phosphatase beta (review).

The impacts of toxins are generally observed as acute intoxications, whereas the environmental health effects of chronic exposure to mostly low levels of toxins are only poorly documented and are an emerging issue. Furthermore, toxins are potentially useful as tools to study the physiological role of particular channels or to determine structural features of channels that are important for their function. Recent studies suggest that vacuolating cytotoxin (VacA) is a novel ligand for receptor protein tyrosine phosphatase (RPTP) beta. VacA is a virulence factor of Helicobacter pylori that is involved in gastric ulceration and cancer in experimental animals and humans. VacA may represent the chronic exposure of A-B family of bacterial endotoxins and be a useful probe for RPTPbeta functions in the gastrointestinal system.

Bacterial Proteins↗
PubMed2002

Cortical involvement for action imitation of hand/arm postures versus finger configurations: an fMRI study.

We used fMRI to study the human imitation of hand/arm postures and finger configuration, subjects imitated hand/arm postures in the hand condition, and they imitated finger configurations in the finger condition. Compared with the control condition, only the finger condition showed significant activation in Broca's area and symmetrical activation in the bilateral inferior parietal lobes, while the hand condition showed left lateralised superior parietal activation pattern. Our findings suggest that Broca's area might be involved more in the imitation of finger configuration than that of hand/arm postures. The result of parietal activation patterns was fully consistent with formerly reported clinical findings, and the relationship between the lesion laterality and the patients' perfomance of hand/finger action imitation.

Adult↗
PubMed2002

A feature-segmentation model of short-term visual memory.

A feature-segmentation model of short-term visual memory (STVM) for contours is proposed. Memory of the First stimulus is maintained until the second stimulus is observed. Three processes interact to determine the relationship between stimulus and response: feature encoding, memory, and decision. Basic assumptions of the model are twofold: (i) the STVM system divides a contour into convex parts at regions of concavity; and (ii) the value of each convex part represented in STVM is an independent Gaussian random variable. Simulation showed that the five-parameter fits give a good account of the effects of the four experimental variables. The model provides evidence that: (i) contours are successfully encoded within 0.5 s exposure, regardless of pattern complexity; (ii) memory noise increases as a linear function of retention interval; (iii) the capacity of STVM, defined by pattern complexity (the degree that a pattern can be handled for several seconds with little loss), is about 4 convex parts; and (iv) the confusability contributing to the decision process is a primary factor in deteriorating recognition of complex figures. It is concluded that visually presented patterns can be retained in STVM with considerable precision for prolonged periods of time, though some loss of precision is inevitable.

Humans↗
PubMed2002

Effects of agouti-related protein, orexin and melanin-concentrating hormone on oxygen consumption in mice.

Neuropeptides in the hypothalamus play a pivotal role in the regulation of energy balance. Agouti-related protein (AGRP), orexin and melanin-concentrating hormone (MCH) have been identified in the hypothalamus as orexigenic peptides. This study was undertaken to investigate the effects of AGRP, orexin and MCH on oxygen consumption. Oxygen consumption was determined by an O2/CO2 metabolism measuring system at 22 degrees C. Mice were kept unrestrained in the chamber without food or water during the light cycle, and the oxygen consumption was measured for 2 h after intra-cerebroventricular (ICV) administration. ICV administered AGRP (1 nmol/mouse) significantly decreased oxygen consumption compared to ACSF-treated controls. Orexin (1 nmol/mouse) significantly increased oxygen consumption, while MCH (1 nmol/mouse) had no significant effect compared to ACSF-treated controls. These results suggest that AGRP, orexin and MCH might have different effects on energy expenditure, thereby regulating appetite and body weight.

Agouti-Related Protein↗
PubMedDate not supplied

Mosapride improves food intake, while not worsening glycemic control and obesity, in ob/ob obese mice with decreased gastric emptying.

Many patients with diabetes mellitus complain of early satiety and postprandial gastric fullness and discomfort. Mosapride citrate, a 5-HT4 receptor agonist, enhances gastric emptying and alleviates gastrointestinal discomfort in patients with diabetic gastroparesis. This study was undertaken to investigate the effects of mosapride citrate on feeding behavior in ob/ob obese mice with decreased gastric emptying. Mosapride citrate (1 mg/kg/day) was orally administered for 7 days. Food and water intake and body weight were measured daily. Blood glucose, serum insulin, and fructosamine concentrations were measured after 7 days of treatment. Orally administered mosapride citrate significantly increased food intake in ob/ob obese mice, with a tendency to decrease fasting blood glucose and fructosamine concentrations compared with controls. There were no significant changes in body weight after 7 days of treatment with oral mosapride citrate. These observations suggest that mosapride citrate may be useful in the treatment of appetite loss and improve the quality of life in patients with diabetes mellitus.

Administration, Oral↗
PubMedDate not supplied

Leptin treatment ameliorates anxiety in ob/ob obese mice.

We investigated whether or not administered leptin influences anxiety-like behavior in ob/ob mice. Repeated intraperitoneal administrations of leptin were continued for 5 days. Anxiety was assessed in the standard elevated plus maze. Body weight was measured daily. Repeated administrations of leptin significantly increased the percentage of the total number of entries in the open arms and the number of total entries. The body weight was significantly reduced by 13.2% after treatment. Leptin treatment ameliorated not only obesity but also anxiety in ob/ob mice. Our results indicate that the treatment of obesity may lead to the solution of psychological problems.

Animals↗