Velocity-dependent EMG activity of masseter and sternocleidomastoideus muscles during a ballistic arm thrusting movement

Two experiments were conducted to investigate the functional relationship between the general somatic motor function and the oral motor function. In Experiment 1, we analyzed the relationship between the amount of masseter muscle (MSS) activity and the velocity of a ballistic, 'karate-do' arm thrusting movement (ThrMov). ThrMov velocity was measured from video images taken with a high-speed CCD camera at a frequency of 500Hz. EMGs of MSS and sternocleidomastoideus (SCM) muscles as well as other related muscles were recorded simultaneously with video images in 6 varsity 'karate-do' athletes. Pearson's correlation coefficients were calculated between EMG amplitude and movement velocity. EMG activity of MSS as well as the other muscles increased as a function of ThrMov velocity in all participants, as evidenced by highly significant (p<.01) correlation coefficients, ranging from .64 to .87 (mean: .75). MSS EMG activity attained during ThrMovs performed at maximum velocity ranged between 14.6% and 113.8% of this muscle's MVC (45.7+/-39.3% MVC, mean+/-SD). SCM was also strongly active and closely associated with MSS. Besides changes in amount of EMG activity, it was further found that R-MSS EMG onset progressively shifted to the earlier phase of the ThrMov as ThrMov velocity increased. EMG onset time of R-MSS as well as R- and L-SCMs was negatively correlated with ThrMov velocity; when performed at maximum velocity MSS activation preceded the start of ThrMov by more than 100ms, whereas MSS was recruited last at approximately 150ms after the start of ThrMov when performed at moderate speed ( approximately 50% of maximum). In Experiment 2, the effects of head movement relative to the trunk on R-MSS and SCMs EMG activity were tested in both gazing and sidelong glancing conditions. A much smaller head rotation relative to the trunk was necessary during the ThrMov in the sidelong glancing condition compared to the gazing condition. R-MSS EMG activity was affected significantly by the difference between these conditions and decreased by 5.2% MVC in the sidelong glancing condition compared to the gazing condition. In association with the change in requirement for head movement between those conditions, EMG balance between the bilateral SCMs changed substantially. Finally, marked muscle activity during ThrMov was found in the MSS that was not directly involved in performing this movement, indicating a form of 'remote facilitation'.     

Effect of spatial position on visual search for 3-D objects

We examined whether the position of objects in external space affects the visual-search task associated with the tilt of 3-D objects. An array of cube-like objects was stereoscopically displayed at a distance of 4.5 m on a large screen 1.5 m above or below eye height. Subjects were required to detect a downward-tilted target among upward-tilted distractors or an upward-tilted target among downward-tilted distractors. When the stimuli consisted of shaded parallelepipeds whose upper/bottom faces were lighter than their side faces, the upward-tilted target was detected faster. This result was in accordance with the 'top-view assumption' reported in previous research. Displaying stimuli in the upper position degraded overall performance. However, when the shaded objects whose upper/bottom faces were darker than their side faces were displayed, the detection of a downward-tilted target became as efficient as that of an upward-tilted target only at the upper position. These results indicate that it is possible for the spatial position of the stimulus to promote the detection of a downward-tilted target when shading and perspective information are consistent with the viewing direction.     

Effects of cementite morphology on short-fatigue-crack propagation in binary Fe–C steel

The effects of cementite morphology on short-fatigue-crack propagation were investigated by subjecting smooth steel specimens to rotating-bending fatigue tests. Intergranular and transgranular cementite precipitation steels free of other phases were prepared through heat treatments. In the intergranular cementite precipitation steel, short-fatigue-crack propagation was decelerated at the grain boundaries, and accelerated in the grain interiors. In contrast, the transgranular precipitation steel showed the deceleration of the crack propagation in the grain interiors but not in the vicinity of the grain boundaries.     

Effects of voice and similarity on procedural fairness and trust: A dual process model of public acceptance based on representatives’ participation

In citizen participation, a few representatives of the total citizen population participate in discussions with authorities regarding public decisions and policies. The present study examines a dual process model in which the representatives’ voice and similarity of values facilitate public acceptance through procedural fairness and trust in representatives, respectively. The results of an experiment employing a scenario method, which included participants from Japan (n = 211) and the Netherlands (n = 200), indicate that the representatives’ voice increased procedural fairness and public acceptance when the similarity of representatives was high. The effects of representatives’ voice on public acceptance via procedural fairness was supported in both nations, while other effects of representatives’ similarity on acceptance via trust were indicated only in Japan. These results suggest that the indirect voice of citizens, as conveyed by representatives, plays an important role in increasing perceptions of procedural fairness and public acceptance among citizens.     

Coping orientation and psychological distress in healthcare professionals: The utility of appraising coping acceptability

The purpose of this study was to examine interaction effects of healthcare professionals' coping orientation (i.e., engagement versus disengagement) and appraisal of coping acceptability (ACA) on psychological distress, taking into account the individuals' job specificity and the psychological climate in their work environment. A cross‐sectional survey was conducted, and Japanese healthcare professionals (N = 189; 117 female; mean age: 40.1 ± 11.2 years) reported the coping strategies that they employed for task‐related or interpersonal stressors, their cognitive appraisal of the stressors, their ACA, and the psychological distress evoked by the stressors. The results showed that adding consideration of the ACA to the variable of coping orientation significantly improved predictions of psychological distress for both task and interpersonal stressors. There was no significant interaction between the coping orientation and the use of coping strategies that incorporated the ACA. These results suggest that considering the ACA, in addition to the coping orientation, would be useful for understanding individual differences in the mediators of healthcare professionals' coping in stressful situations.     

Does high educational level protect against intellectual decline in older adults?: A 10‐year longitudinal study

This study examined the relation between educational level and intellectual change in Japanese older adults. Participants (age = 65–79 years, n = 593) comprised the first‐wave participants of the National Institute for Longevity Sciences‐Longitudinal Study of Aging (NILS‐LSA). They were followed for 10 years and were tested six times. Educational levels were divided into two groups (low‐educated or high‐educated), and intellectual changes for the 10 years were assessed using the Japanese Wechsler Adult Intelligence Scale‐Revised Short Forms (JWAIS‐R‐SF); subtests included Information, Similarities, Picture Completion, and Digit Symbol. General linear mixed‐model analyses revealed that education had not affected 10‐year changes of the Information, Similarities, and Picture Completion subtest scores. In contrast, education was significantly associated with a change in the Digit Symbol subtest score; individuals with higher levels of education showed greater decline than those with less education, although they had higher ability at every time point. These findings suggest that higher education does not protect against intellectual decline in late life, although it is associated with long‐term individual differences in intelligence.     

Recognition of Concrete and abstract Pictures as a Function of Poststimulus Interval

This study examined picture recognition of concrete common objects and abstract random shapes under two presentation conditions: The durations of the unfilled intervals (off-time duration) that followed the presentation of the pictures were varied either randomly or in blocks. The major findings were: (a) recognition of the concrete pictures was better than recognition of random shapes, (b) the off-time duration did not influence recognition of either type of picture under the random presentation condition, and (c) under the block presentation condition, recognition of the concrete pictures increased as a function of off-time duration, whereas the effect of off-time duration was not found for the abstract shapes. The results were interpreted as suggesting that a longer off-time duration is necessary for abstract shapes so that stimulus differentiation, verbal encoding, visual analogizing, and rehearsing may be utilized in processing.     

Eye movement during facial affect recognition by patients with schizophrenia, using Japanese pictures of facial affect

A possible relationship between recognition of facial affect and aberrant eye movement was examined in patients with schizophrenia. A Japanese version of standard pictures of facial affect was prepared. These pictures of basic emotions (surprise, anger, happiness, disgust, fear, sadness) were shown to 19 schizophrenic patients and 20 healthy controls who identified emotions while their eye movements were measured. The proportion of correct identifications of 'disgust' was significantly lower for schizophrenic patients, their eye fixation time was significantly longer for all pictures of facial affect, and their eye movement speed was slower for some facial affects (surprise, fear, and sadness). One index, eye fixation time for "happiness," showed a significant difference between the high- and low-dosage antipsychotic drug groups. Some expected facial affect recognition disorder was seen in schizophrenic patients responding to the Japanese version of affect pictures, but there was no correlation between facial affect recognition disorder and aberrant eye movement.     

The influence of monetary reward and punishment on psychological, physiological, behavioral and performance aspects of a golf putting task

The primary purpose of the present study was to examine kinematic characteristics and force control during a golf-putting task under a pressure condition. The secondary purpose was to provide an exploratory investigation of the relationship between changes in behavior (kinematics and force control) and performance on the one hand, and psychological (attention and affect) and physiological (arousal level) changes on the other hand. Twenty male novices performed 150 acquisition trials, followed by 10 test trials during a pressure condition induced by performance-contingent distracters: a cash reward or punishment. A three-dimensional motion analysis revealed that, during the pressure test, angular displacements of rotational movements at the horizontal plane and movement time of the arms and club during the backswing and downswing phases all decreased, while acceleration of the elbows during the downswing phase increased. Mean performance indices in all participants’ were unchanged in spite of the kinematic changes under the pressure condition. Multiple regression analyses indicated that the decrement in performance, as well as increased variability of movement time and speed, were more likely to increase when participants shifted their attention to movements. Furthermore, changes in heart rate and negative affect were related to both the increase in movement acceleration and a decrease in grip force. These findings suggest that performance and behavioral changes during golf-putting under pressure can be associated with attentional changes, along with the influences of physiological-emotional responses.     

Discrete cortical regions associated with the musical beauty of major and minor chords

Previous research has demonstrated that the degree of aesthetic pleasure a person experiences correlates with the activation of reward functions in the brain. However, it is unclear whether different affective qualities and the perceptions of beauty that they evoke correspond to specific areas of brain activation. Major and minor musical keys induce two types of affective qualities--bright/happy and dark/sad--that both evoke aesthetic pleasure. In the present study, we used positron emission tomography to demonstrate that the two musical keys (major and minor) activate distinct brain areas. Minor consonant chords perceived as beautiful strongly activated the right striatum, which has been assumed to play an important role in reward and emotion processing, whereas major consonant chords perceived as beautiful induced significant activity in the left middle temporal gyrus, which is believed to be related to coherent and orderly information processing. These results suggest that major and minor keys, both of which are perceived as beautiful, are processed differently in the brain.