Changes in somatosensory evoked potentials and Hoffmann reflexes during fast isometric contraction of foot plantarflexor in humans

In the present study, the extent to which the early component of somatosensory evoked potentials (SEPs) and the Hoffmann (H-) reflex induced by stimulation of the posterior tibial nerve are altered during the ascending and descending phases of fast plantarflexion was investigated. SEPSs and H-reflex of the soleus following tibial nerve stimulation were examined during fast plantarfiexion when performed by nine normal subjects. The analyses focused on differences in amplitude modulation of the P30-P40 component of SEP and the H-reflex between the ascending and descending phases of full-wave rectified and averaged soleus electromyographic (EMG) activity. The H-reflex amplitude was significantly increased and decreased during the ascending and descending phases more than under resting control conditions, respectively. The reduction of SEP amplitude was 49% for the ascending phase and 83% for the descending phases with respect to the resting situation. Modulation of SEP during the ascending and descending phases was robustly retained even during ischemic nerve blockade of large diameter afferent fibers. These findings suggest that the transmission of afferent inputs from muscle spindles to motoneurons and to the somatosensory cortex during fast isometric contraction of the plantar flexor is regulated in a time-dependent fashion by descending commands.     

Cultural and linguistic influence on neural bases of 'Theory of Mind': an fMRI study with Japanese bilinguals

Theory of mind (ToM)-our ability to predict behaviors of others in terms of their underlying intentions-has been thought to be universal and invariant across different cultures. However, several ToM studies conducted outside the Anglo-American cultural or linguistic boundaries have obtained mixed results. To examine the influence of culture/language on neural bases of ToM, we studied 16 American English-speaking monolinguals and 16 Japanese-English bilinguals with second-order false-belief story tasks, using functional magnetic resonance imaging (fMRI). Several neural correlates of ToM including medial prefrontal cortex (mPFC) and anterior cingulate cortex (ACC) were recruited by both cultural/linguistic groups. However, some other brain areas including inferior frontal gyrus (IFG) were employed in a culture/language-specific manner, during the ToM tasks. These results suggest that the ways in which adults understand ToM are not entirely universal.     

The "ripple effect": cultural differences in perceptions of the consequences of events

Previous research has demonstrated that people from East Asian cultural backgrounds make broader, more complex causal attributions than do people from Western cultural backgrounds. In the current research, the authors hypothesized that East Asians also would be aware of a broader, more complex distribution of consequences of events. Four studies assessed cultural differences in perceptions of the consequences of (a) a shot in a game of pool, (b) an area being converted into a national park, (c) a chief executive officer firing employees, and (d) a car accident. Across all four studies, compared to participants from Western cultural backgrounds, participants from East Asian cultural backgrounds were more aware of the indirect, distal consequences of events. This pattern occurred on a variety of measures, including spontaneously generated consequences, estimations of an event's impact on subsequent events, perceived responsibility, and predicted affective reactions. Implications for our understanding of cross-cultural psychology and social perception are discussed.     

Are Japanese groups more competitive than Japanese individuals? A cross‐cultural validation of the interindividual–intergroup discontinuity effect

The interindividual–intergroup discontinuity effect is the tendency for relationships between groups to be more competitive than the relationships between individuals. It has been observed robustly in studies conducted in the United States, which is a society characterized as “individualistic.” In this study, it was explored whether the effect was replicable in a “collectivistic” society such as Japan. From the traditional view in cross‐cultural psychology, which emphasizes the collectivistic nature of East Asian peoples, it was expected that the discontinuity effect would be greater in Japan than in the United States. On the other hand, based on recent empirical findings suggesting that North Americans are no less group‐oriented than East Asians, it was expected that the discontinuity effect would be no greater in Japan than in the United States. One hundred and sixty Japanese university students played a 10‐trial repeated prisoner's dilemma game: 26 sessions of interindividual and 18 sessions of intergroup. Following exactly the procedure of prior experiments in the US, individuals and groups were allowed face‐to‐face communication with their opponents before making their decisions, and participants in the intergroup condition were further allowed to converse freely with their in‐group members. Results replicated previous findings in the United States; groups made more competitive choices than did individuals. In addition, neither the magnitude of the discontinuity effect, nor the frequency of competitive choices made by the groups, were larger in Japan than they were in the majority of prior studies conducted in the United States. These findings suggest cross‐cultural robustness of the interindividual–intergroup discontinuity effect. Also, interestingly, they contradict the simple distinction between individualism and collectivism. Implications for studies of culture and group processes are discussed.     

Is chimpanzee (Pan troglodytes) spatial attention reflexively triggered by gaze cue?

Humans show a reflexive shift in spatial attention triggered by gaze cues. Chimpanzees (Pan troglodytes) have an excellent ability to follow another's gaze, but they exhibit a limited capacity to engage in triadic interactions based on joint attention, suggesting the possibility of contributions of the different mechanisms underlying joint attention between humans and chimpanzees. The present study thus examined how the chimpanzee's visual spatial attention is triggered by gaze cues. Two chimpanzees showed no clear signs of attention shift triggered by various kinds of nonfacial and facial stimuli with averted gaze under the letter-discrimination tasks but showed significant cueing effects when the head-turning cue was presented in a quasi-dynamic manner. These cueing effects were, however, affected by the predictability of the gaze cue: Highly predictive gaze cues caused stronger cueing effects than less predictive cues. Thus, these results suggest that the shift in spatial attention caused by gaze cues does occur in chimpanzees, but, in contrast to humans, vulnerability against the cue predictability suggests that the voluntary mechanism contributes more dominantly than the reflexive mechanism to this attention shift.     

Does psychosocial stress exacerbate avoidant responses to cancer information in those who are afraid of cancer? A population-based survey among older adults in England

Objective: Communication of cancer information is an important element of cancer control, but cancer fear may lead to information avoidance, especially when coping is low. We examined the association between cancer fear and cancer information avoidance, and tested whether this was exacerbated by psychosocial stress.

Design: Cross-sectional survey of 1258 population-based adults (58–70 years) in England.

Main outcome measures: Cancer fear (intensity and frequency), perceived psychosocial stress and cancer information avoidance. Control variables were age, gender, ethnicity, marital status and education.

Results: A quarter (24%) of respondents avoided cancer information. Ordinal logistic regression analyses showed main effects of psychosocial stress (OR = 1.17, 95% CI 1.07–1.29) and cancer fear: cancer information avoidance was lowest in those with no cancer fear (13%), followed by those with moderate (24%; OR = 2.15, 95% CI: 1.49–3.12), and high cancer fear (35%; OR = 3.90, 95% CI: 2.65–5.73). In the adjusted model, the interaction between cancer fear and stress was significant (OR = 1.14, 95% CI 1.004–1.29, p < .05): 40% of those with high fear/high stress avoided cancer information compared with 29% with high fear/low stress.

Conclusion: Cancer fear and psychosocial stress interact to produce disengagement with cancer-related information, highlighting the importance of affective processes to cancer control efforts.     

Subliminal gaze cues increase preference levels for items in the gaze direction

Another individual’s gaze automatically shifts an observer’s attention to a location. This reflexive response occurs even when the gaze is presented subliminally over a short period. Another’s gaze also increases the preference level for items in the gaze direction; however, it was previously unclear if this effect occurs when the gaze is presented subliminally. This study showed that the preference levels for nonsense figures looked at by a subliminal gaze were significantly greater than those for items that were subliminally looked away from (Task 1). Targets that were looked at by a subliminal gaze were detected faster (Task 2); however, the participants were unable to detect the gaze direction (Task 3). These results indicate that another individual’s gaze automatically increases the preference levels for items in the gaze direction without conscious awareness.