Autonomic activity, pain, and perceived health in patients on sick leave due to stress-related illnesses

Objective: The aim of the present study was to compare autonomic activity, pressure-pain thresholds, and subjective assessments of health and behavior between patients with stress-related illnesses and healthy control subjects.Methods: Twenty sick-listed patients with stress-related illnesses and 20 age- and gender-matched healthy subjects performed tests of autonomic regulation and algometric tests, and completed questionnaires about physical and mental health and behavioral patterns.Results: Patients exhibited higher autonomic reactivity to cognitive and physical laboratory tasks (p<0.05), and had lower pressure-pain thresholds in the shoulders and lower back than healthy control subjects (p<0.05). Furthermore, the patients rated considerably poorer health and health behavior than the control subjects (p<0.05).Conclusions: The results indicate an engagement of the autonomic nervous system in stress-related illnesses. Furthermore, they show that patients with stress-related illnesses experience symptoms of musculoskeletal pain, and it is therefore recommended that assessments of musculoskeletal pain be incorporated in the clinical examinations and the rehabilitation of patients with stress-related illnesses.     

Influence of instruction on evaluation of repeated muscular endurance

This study was done to examine the influence of instructions on the evaluation of rhythmic repeated muscular endurance, that is, the ability to continue muscle-power exertion at a regular interval. 15 healthy young male adults performed maximal repeated rhythmic grips for 6 min. under the following three instruction conditions: (1) "Squeeze freely during the 2-sec. interval," (2) "Squeeze quickly and then relax," and (3) "Squeeze quickly and then hold the exertion for 1 sec." Time to peak force was slower in Condition 1 than in Condition 2. A decline in exertion of force was found for all conditions after 1 min. The decline in rate of the peak values in Conditions 1 and 3 was about 10 to 15% larger than that of Condition 2. In conclusion, proper instructions are necessary, even for a short 2-sec. interval, when evaluating muscular endurance with repeated rhythmic grips. Condition 2 instruction may be most effective.     

Similarity attraction and actually selecting similar others: How cross-societal differences in relational mobility affect interpersonal similarity in Japan and the USA

Several studies have demonstrated that similarity between friendship partners is higher in the West than in East Asian countries. We hypothesized that these differences could be explained by relational mobility, or the number of opportunities to form new relationships in a given society. Through two studies, we confirmed that whereas the preference for similarity did not differ, similarity between friendship partners was higher in the USA than in Japan. Furthermore, a measure of relational mobility mediated the cultural difference in similarity, supporting our hypothesis. The effectiveness of considering socio-ecological factors when interpreting cultural differences in behaviour is discussed.     

Evaluation of human consciousness level by means of “automated fluctuation analysis” of high frequency electroencephalogram fitted by double Lorentzians

Since Berger’s discovery of the electroencephalogram (EEG), its analysis has been generally restricted to the visual range (upmost 100Hz) and has ignored higher frequency components. One reason should be that there are no reliable methods to distinguish the brain potentials from muscle activity. We have introduced fluctuation analysis, which is popular method especially in the field of basic physiology to clinical electrophysiology. In our previous study, it was declared that power spectral density (PSD) of human high frequency EEG was composed of double Lorentzians and vanished into white level within 1kHz. Then the purpose of this study is to elucidate the “Automated Fluctuation Analysis,” which enables us to evaluate these higher frequency components and its physiological meaning especially focused on conscious level from wakefulness to sleep stage 1. Seventy-four scalp recording EEGs in twenty normal subjects were studied. In short, “Automated Fluctuation Analysis” is made of three steps: amplification of EEG signal, A/D conversion and Fast Fourier Transform by signal processor and extraction of Lorentzian parameters. PSD of high frequency EEG was displayed on log-log graph and the algorithm fit to the following Lorentzian formula were mathematically based on Brown & Dennis. S(f)=S1/ [1+(f/fc₁)²] + S2/ [1+(f/fc₂)²], where S(f) is PSD (μ V²/Hz) at each frequency (f;Hz), S1 and S2 are the plateau level or zero-frequency power of the initial and second Lorentz, and fc₁ and fc₂ are the corner or half-power frequency of the initial and second Lorentz, respectively. As results, during wakefulness the PSD of high frequency EEG activity was composed of double Lorentzian fluctuations and the power distribution of S1 value in topographical display was frontal dominant. This pattern of S1 value disappeared and S2 value became lower during sleepiness and the second Lorentz disappeared during sleep.     

Effects of facial expression and gaze direction on approach-avoidance behaviour

Humans must coordinate approach-avoidance behaviours with the social cues that elicit them, such as facial expressions and gaze direction. We hypothesised that when someone is observed looking in a particular direction with a happy expression, the observer would tend to approach that direction, but that when someone is observed looking in a particular direction with a fearful expression, the observer would tend to avoid that direction. Twenty-eight participants viewed stimulus faces with averted gazes and happy or fearful expressions on a computer screen. Participants were asked to grasp (approach) or withdraw from (avoid) a left- or right-hand button depending on the stimulus face's expression. The results were consistent with our hypotheses about avoidance responses, but not with respect to approach responses. Links between social cues and adaptive behaviour are discussed.     

Effects of tilted orientations and face-like configurations on visual search asymmetry in macaques

Visual search asymmetry has been used as an important tool for exploring cognitive mechanisms in humans. Here, we examined visual search asymmetry in two macaques toward two types of stimulus: the orientation of line stimuli and face-like stimuli. In the experiment, the monkeys were required to detect an odd target among numerous uniform distracters. The monkeys detected a tilted-lines target among horizontal- or vertical-lined distracters significantly faster than a horizontal- or vertical-lined target among tilted-lined distracters, regardless of the display size. However, unlike the situation in which inverted-face stimuli were introduced as distracters, this effect was diminished if upright-face stimuli were used as distracters. Additionally, monkeys detected an upright-face target among inverted-face distracters significantly faster than an inverted-face target among upright-face distracters, regardless of the display size. These results demonstrate that macaques can search a target efficiently to detect both tilted lines among non-tilted lines and upright faces among inverted faces. This clarifies that there are several types of visual search asymmetry in macaques.     

Infants’ responsiveness to maternal speech and singing

Infants who were 6 months of age were presented with extended audiovisual episodes of their mother's infant-directed speech or singing. Cumulative visual fixation and initial fixation of the mother's image were longer for maternal singing than for maternal speech. Moreover, movement reduction, which may signal intense engagement, accompanied visual fixation more frequently for maternal singing than for maternal speech. The stereotypy and repetitiveness of maternal singing may promote moderate arousal levels, which sustain infant attention, in contrast to the greater variability of speech, which may result in cycles of heightened arousal, gaze aversion, and re-engagement. The regular pulse of music may also enhance emotional coordination between mother and infant.     

Cooperative strain accommodation over grains in martensitic transformation from Fe-Ni nanocrystalline austenite

This paper reports an investigation of martensitic transformation behaviour from austenite with various grain sizes ranging from 290 nm to 34 μm in an Fe–Ni alloy fabricated by electrodeposition and subsequent heat treatment. We confirmed that martensite morphology changed from lath to thin plate with decreasing the austenite grain size. Crystallographic orientation analysis revealed that the variants of thin plate martensite formed in the austenite with relatively coarse grains achieved self-accommodation of the transformation strain inside one austenite grain. In contrast, the transformation strain accompanying martensitic transformation from the ultrafine-grained or nanocrystalline austenite was not accommodated by the martensite variants formed in one austenite grain but accommodated cooperatively by those formed in the several adjacent austenite grains.     

Modulations of muscle modes in automatic postural responses induced by external surface translations

The authors applied principal component analysis to investigate muscle activation patterns (M-modes) involved in the automatic postural responses induced by external surface perturbations. They focused on M-mode modulations as responses to the effects of practice, stability of the conditions and perturbed directions. While peak center of mass velocity reduced with practice, M-modes were similar with practice and across stability conditions. In contrast, atypical sway mode coactivations that combined proximal trunk muscles with distal muscles of the opposite lower extremity of the ventral-dorsal side were observed under the unstable conditions in both forward and backward perturbations after practice. In addition, M-modes in the forward translations were characterized by increased cocontraction patterns. Results suggest that compositions of the underlying M-modes show minor differences in each perturbed direction, but practice enhances coactivation patterns combining proximal muscles with distal muscles, and with accompanying cocontraction patterns, under more challenging conditions.     

Negative support of significant others affects psychological adjustment in breast cancer patients

Significant others play an important role in providing support in patients' lives, but some types of support negatively affect the patients. This study was conducted in early-stage breast cancer patients to examine the structure of support, which was provided by their significant others and assessed negatively by the patients, and to identify negative support relating to the psychological adjustment of these patients. Thus, we first conducted interviews among 28 breast cancer patients to identify these support items assessed as negative; next, we conducted a questionnaire survey using the resulting items in 109 postoperative patients who had early-stage breast cancer. We performed exploratory and confirmatory factor analyses and obtained a valid second-order factor structure, including superordinate factors (excessive engagement, avoidance of problems and underestimation) and subordinate factors (overprotection, encouragement and management). Among these factors, the avoidance of problems was the only factor to be negatively associated with psychological adjustment of the patients, suggesting that these patients receive problem-avoiding support. The results of our study suggest that such problem-avoiding support from significant others can be counter-productive and potentially worsen the psychological adjustment of breast cancer patients.