Suppressive control of optokinetic and vestibular nystagmus by the primate frontal eye field.

When the eyes are fixated on a spot, fixation neurons in the frontal eye field (FEF) show an increase in activity. Our previous study suggested that fixation neurons in the FEF contribute to the suppression of saccades and smooth pursuit eye movements to maintain active fixation. The present study examined the role of the FEF in the suppressive control of reflexive eye movements, optokinetic and vestibular nystagmus, in trained monkeys. Electrical stimulation in the FEF suppressed the quick and slow phases of optokinetic and vestibular nystagmus at an intensity lower than the threshold for eliciting electrically evoked saccades. Relatively weak suppression influenced the slow phase of vestibular nystagmus. During optokinetic or vestibular nystagmus, presentation of a stationary small spot to the eyes followed by fixation is known to suppress both the quick and slow phases of eye movements. We recorded the activity of fixation neurons in the FEF and found that fixation neurons usually showed a decrease in activity during optokinetic and vestibular nystagmus and an increase in activity during the suppression of nystagmus by visual fixation. The present results show that the activity of fixation neurons in the FEF is related to the suppressive control of optokinetic and vestibular nystagmus for maintaining active fixation. We discuss the role of a generalized visual fixation system that can maintain visual attention on an interesting object.NEW & NOTEWORTHY In this study, electrical stimulation in the frontal eye field (FEF) suppressed the quick and slow phases of optokinetic and vestibular nystagmus at an intensity subthreshold for eliciting saccades. Furthermore, the activity of fixation neurons in the FEF was related to the suppression of optokinetic and vestibular nystagmus by visual fixation. This suggests that a common neuronal assembly in the FEF may contribute to the suppressive control of different functional classes of eye movements.

Motor action of the frontal eye field on the eyes and neck in the monkey.

Focal stimulation in the frontal eye field (FEF) evoked eye movements that were often accompanied by neck movements. Experiments were performed with concurrent recording of both movements in trained monkeys. We recorded neck forces under a head-restrained condition with a force-measuring system. With the system, we measured forces along the x-, y-, and z-axes and torque about the z-axis. Torque about the z-axis that represented yaw rotation of the head was significantly affected by stimulation. We found that stimulation generated two types of motor actions of the eyes and neck. In the first type, contraversive neck forces were evoked by stimulation of the medial part of the FEF, where contraversive saccadic eye movements with large amplitudes were evoked. When the stimulus intensity was increased, saccades were evoked in an all-or-none manner, whereas the amplitude of neck forces increased gradually. In the second type, contraversive neck forces were evoked by stimulation of the medial and caudal part of the FEF, where ipsiversive slow eye movements were evoked. The depth profiles of amplitudes of neck forces were almost parallel to those of eye movements in individual stimulation tracks. The present results suggest that the FEF is involved in the control of motor actions of the neck as well as the eyes. The FEF area associated with contraversive saccades and contraversive neck movements may contribute to a gaze shift process, whereas that associated with ipsiversive slow eye movements and contraversive neck movements may contribute to a visual stabilization process. NEW & NOTEWORTHY Focal stimulation in the frontal eye field (FEF) evoked eye and neck movements. We recorded neck forces under a head-restrained condition with a force-measuring system. Taking advantage of this approach, we could analyze slow eye movements that were dissociated from the vestibuloocular reflex. We found ipsiversive slow eye movements in combination with contraversive neck forces, suggesting that the FEF may be a source of a corollary discharge signal for compensatory eye movements during voluntary neck movements.

Magnetic-field-induced phase separation via spinodal decomposition in epitaxial manganese ferrite thin films.

In this study, we report about the occurrence of phase separation through spinodal decomposition (SD) in spinel manganese ferrite (Mn ferrite) thin films grown by Dynamic Aurora pulsed laser deposition. The driving force behind this SD in Mn ferrite films is considered to be an ion-impingement-enhanced diffusion that is induced by the application of magnetic field during film growth. The phase separation to Mn-rich and Fe-rich phases in Mn ferrite films is confirmed from the Bragg's peak splitting and the appearance of the patterned checkerboard-like domain in the surface. In the cross-sectional microstructure analysis, the distribution of Mn and Fe-signals alternately changes along the lateral (x and y) directions, while it is almost homogeneous in the z-direction. The result suggests that columnar-type phase separation occurs by the up-hill diffusion only along the in-plane directions. The propagation of a quasi-sinusoidal compositional wave in the lateral directions is confirmed from spatially resolved chemical composition analysis, which strongly demonstrates the occurrence of phase separation via SD. It is also found that the composition of Mn-rich and Fe-rich phases in phase-separated Mn ferrite thin films deposited at higher growth temperature and in situ magnetic field does not depend on the corresponding average film composition.

Activity of fixation neurons in the monkey frontal eye field during smooth pursuit eye movements.

We recorded the activity of fixation neurons in the frontal eye field (FEF) in trained monkeys and analyzed their activity during smooth pursuit eye movements. Fixation neurons were densely located in the area of the FEF in the caudal part of the arcuate gyrus facing the inferior arcuate sulcus where focal electrical stimulation suppressed the generation of saccades and smooth pursuit in bilateral directions at an intensity lower than the threshold for eliciting electrically evoked saccades. Whereas fixation neurons discharged tonically during fixation, they showed a variety of discharge patterns during smooth pursuit, ranging from a decrease in activity to an increase in activity. Of these, more than two-thirds were found to show a reduction in activity during smooth pursuit in the ipsilateral and bilateral directions. The reduction in activity of fixation neurons began at pursuit initiation and continued during pursuit maintenance. When catch-up saccades during the initiation of pursuit were eliminated by a step-ramp target routine, the reduced activity of fixation neurons remained. The reduction in activity during pursuit was not dependent on the activity during fixation without a target. Based on these results, we discuss the role of the FEF at maintaining fixation in relation to various other brain areas. We suggest that fixation neurons in the FEF contribute to the suppression of smooth pursuit. These results suggest that FEF fixation neurons are part of a more generalized visual fixation system through which suppressive control is exerted on smooth pursuit, as well as saccades.

Strain engineering effects on electrical properties of lead-free piezoelectric thin films on Si wafers.

Using radio frequency - magnetron sputtering, calcium-doped barium zirconate titanate ((Ba(0.85)Ca(0.15))(Zr(0.1)Ti(0.9))O(3), BCZT) thin films were deposited on Si wafers with different bottom electrodes. The obtained BCZT thin film on a lanthanum nickel oxide (LNO) electrode had a highly c-axis preferred orientation, while the BCZT thin film on a Pt bottom electrode had (111) preferred orientation. Furthermore, the out-of-plane lattice constant of the BCZT on LNO/Si was 3.4% larger than that of the reported bulk material because of the compressive thermal stress from LNO with a large thermal expansion coefficient. This compressive thermal stress engenders an increase of the Curie temperature. The local piezoelectric response of the BCZT thin film on a LNO/Si structure was measured by piezoresponse force microscope.

Suppression of smooth pursuit eye movements induced by electrical stimulation of the monkey frontal eye field.

This study was performed to characterize the properties of the suppression of smooth pursuit eye movement induced by electrical stimulation of the frontal eye field (FEF) in trained monkeys. At the stimulation sites tested, we first determined the threshold for generating electrically evoked saccades (Esacs). We then examined the suppressive effects of stimulation on smooth pursuit at intensities that were below the threshold for eliciting Esacs. We observed that FEF stimulation induced a clear deceleration of pursuit at pursuit initiation and also during the maintenance of pursuit at subthreshold intensities. The suppression of pursuit occurred even in the absence of catch-up saccades during pursuit, indicating that suppression influenced pursuit per se. We mapped the FEF area that was associated with the suppressive effect of stimulation on pursuit. In a wide area in the FEF, suppressive effects were observed for ipsiversive, but not contraversive, pursuit. In contrast, we observed the bilateral suppression of both ipsiversive and contraversive pursuit in a localized area in the FEF. This area coincided with the area in which we have previously shown that stimulation suppressed the generation of saccades in bilateral directions and also where fixation neurons that discharged during fixation were concentrated. On the basis of these results, we compared the FEF suppression of pursuit with that of saccades with regard to several physiological properties and then discussed the role of the FEF in the suppression of both pursuit and saccades, and particularly in the maintenance of visual fixation.

Fabrication of two-dimensional close-packed shell structure in ceramic thin films.

TiO2 thin films with a periodical two-dimensional close-packed hemispherical structure were prepared on Si substrates using pulsed laser deposition and close-packed monolayer polystyrene colloidal crystals as a template. Compared with conventional methods, which use a top-down approach, this route supports low-cost production of a periodic structure. Additionally, it is applicable to various ceramics for use in applications related to photonic crystals, surface self-cleaning materials, data storage media, bioassays, and so on.

Magnetic and optical properties of MgAl2O4-(Ni0.5Zn0.5)Fe2O4 thin films prepared by pulsed laser deposition.

Thin films composed of MgAl2O4 and (Ni0.5Zn0.5)Fe2O4 ([MA(100-x)-NZFx] films) were grown on fused SiO2 substrates by pulsed laser deposition. X-ray diffraction measurements revealed that the films were polycrystalline, and that their lattice constant varied linearly with composition, indicating the formation of a solid solution. The film with x=60 was paramagnetic and those with x ≥ 70 were ferromagnetic. The films had a transparency above 75% in the visible range, but the transparency decreased with the x value. The optical band gaps were 2.95, 2.55, 2.30 and 1.89 eV for x=20, 40, 60, 80 and 100, respectively. The Faraday rotation angle increased with x in the visible range, and the film with x=70 exhibited a value of 2000 degrees cm-1 at 570 nm, which is comparable to the rotation angle of Y3Fe5O12. Owing to their high transparency, which extends into the visible range, the [MA(100-x)-NZFx] films can be used in novel magneto-optical devices.

Response properties of fixation neurons and their location in the frontal eye field in the monkey.

Electrical stimulation of the frontal eye field (FEF) has recently been reported to suppress the generation of saccades, which supports the idea that the FEF plays a role in maintaining attentive fixation. This study analyzed the activity of fixation neurons that discharged during fixation in the FEF in relation to visual fixation and saccades in trained monkeys. The neural activity of fixation neurons increased at the start of fixation and was maintained during fixation. When a fixation spot of light disappeared during steady fixation, different fixation neurons exhibited different categories of response, ranging from a decrease in activity to an increase in activity, indicating that there is a continuum of fixation neurons, from neurons with foveal visual-related activity to neurons with activity that is related to the motor act of fixating. Fixation neurons usually showed a decrease in their firing rate before the onset of visually guided saccades (Vsacs) and memory-guided saccades in any direction. The reduction in activity of fixation neurons nearly coincided with, or occurred slightly before, the increase in the activity of saccade-related movement neurons in the FEF in the same monkey. Although fixation neurons were scattered in the FEF, about two thirds of fixation neurons were concentrated in a localized area in the FEF at which electrical stimulation induced strong suppression of the initiation of Vsacs bilaterally. These results suggest that fixation neurons in the FEF are part of a suppression mechanism that could control the maintenance of fixation and the initiation of saccades.

Relationship of psychological factors with physical activity stage of change in prime-and middle-aged Japanese.

The present study aimed to investigate the status of physical activity and the differences in psychological factors associated with physical activity from the perspective of transtheoretical model stages between prime- and middle-aged Japanese. The study involved 375 prime-aged volunteers (175 men, 200 women) and 557 middle-aged volunteers (247 men, 310 women) living in Kuse, a town in Okayama Prefecture, Japan. We found that the prime-aged men at the preparation stage had significantly higher self-efficacy scores than at the contemplation stage (p<0.01). Middle-aged men had significantly higher self-efficacy scores at the contemplation stage than at the precontemplation stage (p<0.001). Middle-aged women, meanwhile, had significantly higher self-efficacy scores at the maintenance stage than at the action stage (p<0.01), and at the contemplation stage than at the precontemplation stage (p<0.001). The present findings provide valuable information about the differences in psychological factors affecting physical activity between prime-aged and middle-aged community-dwelling Japanese. This information may be useful to health professionals as they develop effective community-based intervention programs for target populations.

Non-Fermi Liquids as Highly Active Oxygen Evolution Reaction Catalysts.

The oxygen evolution reaction (OER) plays a key role in emerging energy conversion technologies such as rechargeable metal-air batteries, and direct solar water splitting. Herein, a remarkably low overpotential of ≈150 mV at 10 mA cm-2disk in alkaline solutions using one of the non-Fermi liquids, Hg2Ru2O7, is reported. Hg2Ru2O7 displays a rapid increase in current density and excellent durability as an OER catalyst. This outstanding catalytic performance is realized through the coexistence of localized d-bands with the metallic state that is unique to non-Fermi liquids. The findings indicate that non-Fermi liquids could greatly improve the design of highly active OER catalysts.

Psychosocial Determinants of Fruit and Vegetable Consumption in a Japanese Population.

There is limited evidence in Japan regarding the psychosocial determinants of fruit/vegetable intake. We performed a cross-sectional study of people aged 18 years or older in four regions of Japan; 2308 (men: 1012, women: 1296) individuals who completed the questionnaires were included. We found that 24.8% of people were aware of the current recommendations for vegetables and 13.2% for fruit and that "ability to design meals" and "availability when eating outside of the home" were the most important factors related to self-efficacy and barriers to fruit and vegetable intake, respectively. People with high self-efficacy (OR: 3.16; 95% CI: 2.17, 4.60 for fruit; OR: 4.52; 95% CI: 3.08, 6.64 for vegetables) were more likely to consume more fruit and vegetables. People with high scores on attitude (OR: 1.54; 95% CI: 1.06, 2.24) and social support (OR: 1.59; 95% CI: 1.11, 2.27) were more likely to consume more fruit. People with high perceived barriers (OR: 0.69; 95% CI: 0.48, 0.98) were less likely to consume fruit. This study suggests a need to increase the general population's awareness of the fruit and vegetable intake recommendations; facilitating positive attitudes, self-efficacy, and social support for individuals and strengthening the ability of individuals to design meals with more vegetables and fruit might be useful intervention programs.

Initiation and suppression of saccades by the frontal eye field in the monkey.

After a saccadic eye movement occurs to an interesting object appearing in the visual field, visual fixation holds its image on the fovea and suppresses saccades to other objects appearing in the visual field. To understand the neural mechanism of visual fixation, the effects of electrical stimulation of the frontal eye field (FEF) on the generation of electrically evoked saccades (Esacs) and the suppression of saccades in trained monkeys were investigated. When the properties of the electrically evoked suppression of visually guided (Vsacs) and memory-guided saccades (Msacs) were examined, two types of suppression were found. Stimulation of a wide area of the FEF suppressed only ipsiversive Vsacs and Msacs at stimulus intensities lower than those for eliciting Esacs, whereas stimulation of a localized area of the FEF suppressed the initiation of both Vsacs and Msacs in any direction during and approximately 50 ms after stimulation. However, neither stimulation affected the vector of these saccades. The thresholds for suppression were usually less than 50 microA. The most effective stimulation timing for the suppression of ipsiversive and contraversive Vsacs was approximately 40 to 50 ms before saccade onset. Therefore, suppression occurred in the efferent pathway for Vsacs at the premotor rather than the motoneuronal level, most likely in the superior colliculus and/or the paramedian pontine reticular formation. The results suggest that the suppression in the FEF may play a role in maintaining visual fixation by suppressing the generation of saccades.

Daily exercise lowers blood pressure and reduces visceral adipose tissue areas in overweight Japanese men.

OBJECTIVE: To investigate the link between a reduction in blood pressure (BP) and daily exercise. DESIGN: Cross-sectional and longitudinal clinical intervention study with exercise education. SUBJECTS: 43 overweight Japanese men aged 32-59 years (BMI, 29.0+/-2.3 kg/m2) at baseline. Among the participants, a randomly selected 23 overweight men (BMI, 28.5+/-1.7) were further enrolled into the 10 months exercise program. MEASUREMENTS: BP was measured every week and steps per day were also recorded every day throughout the observation period. Fat distribution was evaluated by visceral fat (V) and subcutaneous fat (S) areas measured with computed tomography (CT) scanning at umbilical level, at before, 5 months and after intervention. Anthropometric parameters were also measured at same point. Aerobic exercise level, muscle strength, flexibility and calorie intake and insulin resistance (HOMA index) were investigated at before and after the study. RESULTS: In a cross sectional analysis, systolic BP (SBP) and diastolic BP (DBP) were significantly correlated with body composition. In a second longitudinal analysis, SBP was significantly reduced at 2 months and DBP was also reduced at 3 months, and almost maintained until the end of the observation period. Increasing daily walking was observed in 3 months and maintained until 10 months. Body composition, aerobic exercise level, muscle strength, flexibility and insulin resistance were significantly improved. There was positive correlation between DeltaDBP and Deltavisceral fat area (1-5, 5-10, 1-10 months). By stepwise multiple regression analysis, only Deltavisceral fat area was independently related to DeltaDBP at a significant level (1-10 months: DeltaDBP=-0.608+0.105Deltavisceral fat area, r2=0.227, P=0.0334). CONCLUSION: The present study indicated daily exercise lowers BP and visceral fat area is the critical factor for BP change.

Daily walking reduces visceral adipose tissue areas and improves insulin resistance in Japanese obese subjects.

OBJECTIVE: It is known that the accumulation of abdominal fat is one of the risk factors for atherosclerosis. Although exercise is commonly prescribed to reduce body weight, the efficacy of low intensity exercise for the reduction of abdominal visceral adipose tissue remains to be investigated. RESEARCH DESIGN AND METHODS: Thirty one obese Japanese males (body mass index (BMI) > or = 25) ranging in age from 32 to 59, participated in a 1-year follow up study and they were instructed to have a modest increase in daily activity and record their daily walking. Before and after exercise prescription, body composition, blood pressure, physical fitness i.e. aerobic exercise level, muscle strength and flexibility were recorded. Insulin resistance was evaluated using a homeostasis model assessment, the HOMA index. RESULTS: HOMA index, parameters of body composition, blood pressure, triglyceride and HDL cholesterol were significantly improved. The aerobic exercise level, leg strength, weight-bearing index (leg strength/body weight) and the steps taken per day were significantly increased. By stepwise multiple regression analysis, Delta visceral adipose tissue area was the major determinant for Delta HOMA index. (Delta HOMA index=-0.386+0.016 Delta visceral adipose tissue area, r2=0.267, P<0.01). Exercise capacity and calorie intake were not significantly related to Delta visceral adipose tissue area, while Delta steps per day was significantly correlated with Delta visceral adipose tissue area (Delta visceral adipose tissue area=-21.363-0.004 Delta steps per day, r2=0.184, P=0.0326). CONCLUSIONS: Taken together, intra-abdominal visceral adipose tissue is critically involved in insulin resistance and daily walking rather than improvement of exercise capacity correlated with the reduction of visceral adipose tissue in obese Japanese males.

Psychological determinants of physical activity in Japanese female employees.

To understand how psychological characteristics influence adoption and maintenance of physical activity/exercise, we conducted a cross-sectional study among Japanese employees based upon the idea of stages of behavior modification. The study population consisted of 719 employees (male, 396, female, 323) from five medium-sized manufacturing companies (50-200 employees) in Okayama Prefecture, Japan. The female response rate was 67.5% (n=218), among which 201 eligible female subjects (62.2%) were analyzed. The study questionnaire included demographic characteristics, physical activity/exercise measures, self-efficacy measures, and perceived benefit and barriers scales. Participants were asked to select the items that best described their current physical activity/exercise level from an 8-item questionnaire, and we converted their answers to the 5 stages of change according to a transtheoretical model of behavior change. Perceived benefit and barrier scales were classified into 7 factors (4 benefits and 3 barriers) by factor analyses. The relationship between psychological determinants and the stage of physical activity/exercise was examined by one-way analysis of variance. Only 10% of the subjects had moderate physical activity (in the action and maintenance stages) regularly. We found that self-efficacy, "weight control benefit", "physical barrier" and "time barrier" were psychological determinants of physical activity/exercise stages in female employees, and especially there was a consistent relationship between self-efficacy and the stage of physical activity/exercise. Our data suggest that health education for Japanese female employees requires that health professionals should provide support for strengthening self-efficacy, show practical ways to increase physical activity in daily life, and provide broad and accurate information showing that physical activity/exercise have a good effect on health.

[Evaluation of an exercise program for obese males].

PURPOSE: We developed a one-year exercise program based on evaluation of life style and physical fitness and investigated its efficacy. SUBJECTS AND METHODS: Sixty one Japanese males (30 < or = age < 59, body mass index: BMI > or = 26.4 kg/m2) were enrolled in the stady. The exercise program consisted of four sections: (1) Preparation for preventing injury; (2) Increase of daily activity; (3) Enjoying exercise; (4) Preparation and practice of individual-based on a exercise program. The subjects visited Okayama Southern Institute of Health and were being monitored weekly for one-year. They were instructed to check daily steps every day and increase daily walking to at least 1000 steps more than the daily walk at baseline. Before and after one-year follow up study, we evaluated life style and physical fitness in terms of body composition, aerobic exercise level, muscle strength and flexibility. RESULTS: The continuation rate for the program was 66%. Body weight (pre 81.5 +/- 7.4 kg vs post 78.6 +/- 7.3 kg), body fat percentage (pre 30.3 +/- 4.1% vs post 28.4 +/- 5.0%) and waist hip ratio (pre 0.95 +/- 0.04 vs post 0.92 +/- 0.04) were significantly reduced. Aerobic exercise level and muscle strength were increased. Regarding volition for exercise, execution, continuation and steps per day were also improved. CONCLUSION: Regular exercise at an institution (once a week) and change in daily life style may play critical role in reducing body weight. This new program proved quite useful for Japanese obese males.

One-year outcome of an interactive internet-based physical activity intervention among university students.

OBJECTIVE: The purpose of the present study was to evaluate whether improvement in physical activity of students following a 4-month intervention of a university course was maintained 8 months later. METHODS: Data on 77 students who responded to our scheduled inquiries completely through 1 year were analyzed. Participants of the intervention group (n=49) using the internet-based physical activity program exhibited significant increases in energy expenditures measured by IPAQ compared with the no-treatment control group (n=28) through 1 year. RESULTS: Participants who did not engage in regular university sports activities (baseline: 450±351kcalday(-1); post: 587±320kcalday(-1); 8-month follow-up: 580±394kcalday(-1)) only exhibited significant increases in energy expenditures compared with those of the control group (baseline: 498±341kcalday(-1); post: 414±242kcalday(-1); 8-month follow-up: 347±275kcalday(-1)). CONCLUSION: These results suggested that an internet-based interactive intervention could become a helpful tool in promoting and maintaining physical activity in the long term.

Phase diagram and piezoelectric response of (Ba1-xCax)(Zr0.1Ti0.9)O3 solid solution.

We report the phase diagram of (Ba1-xCax)(Zr0.1Ti0.9)O3 solid solution. It is found that substitution of smaller Ca ions for Ba ions can slightly increase the cubic-tetragonal (T) para-ferroelectric phase transition temperature and strongly decrease the T-orthorhombic (O) and O-rhombohedral (R) transition. This unique ferroelectric phase evolution is attributed to Ca off-centering effects. More importantly, lowering of the T-O or O-R phase transitions allows us to prepare the piezoelectric ceramics with a strain response as high as S/E ≈ 800 pm V(-1) (E = 10 kV cm(-1)) over a wide range of compositions with x ≈ 0.1-0.18 at room temperature, which may be interesting for piezoelectric applications.

Expression of an RSV-gag virus-like particle in insect cell lines and silkworm larvae.

Rous sarcoma virus group antigen protein-based virus-like particles (VLPs) are well known for their structural integrity and ease of handling. VLPs play an important role in drug delivery systems because they can be manipulated with ease. In this study, a new method was established for expressing Rous sarcoma virus group antigen protein based VLPs in silkworm larvae and establishing stably expressing insect cell lines. These VLPs have been isolated by ultracentrifugation using a sucrose step gradient of 10-60% (v/v), and their spherical structure has been confirmed using transmission electron microscopy (TEM). The spherical morphology is similar in both the silkworm larvae and in stably expressing cell lines. Silkworm larvae are better suited for producing Rous sarcoma virus group antigen protein-based VLPs on a large scale; yields from silkworm larvae were approximately 8.2-fold higher than yields from stable cell lines. These VLPs provide a new method for large-scale application in vaccine development and drug delivery systems.