Biomedical subjects

Jun Shigemura

Publications and source records attributed to Jun Shigemura.

7 recordsLinked to original sources

PubMed2006

Activation time course of responses to illusory contours and salient region: a high-density electrical mapping comparison.

Until recently, early visual areas (V1/V2) were believed to respond mainly to illusory contours (ICs). At present, however, functional neuroimaging suggests that the human lateral occipital complex (LOC), a higher tier than V2, responds strongly to ICs and that IC-related activation in V1/V2 in fact might be driven by feedback input from the LOC. When Kanizsa-type ICs are modified by rounding the corners of the inducers and misaligning them slightly, the impression of an enclosed salient region (SR) remains, although ICs no longer are perceived. Stanley and Rubin (Stanley, D.A., Rubin, N., 2003. fMRI activation in response to illusory contours and salient regions in the human lateral occipital complex. Neuron, 37, 323-331) found that the LOC responded to SR, suggesting that the LOC subserves a rapid but crude region-based segmentation process preceding boundary completion in V1/V2. The present study compared the time course of cortical responses to ICs with those to SR using high-density (74-channel) event-related potentials (ERPs). Scalp mapping and statistical analysis indicated that shared negative modulation for ICs and SR was distributed bilaterally over the lateral occipital scalp at a latency of 70 to 180 ms. Slightly later, a weak negative modulation occurred with ICs but not SR at the occipital pole scalp from 170 to 180 ms. Dipoles for early and late modulations were fitted optimally in the LOC and occipital pole, respectively. The present results suggested that IC-related cortical activation could be separated into region-based segmentation and subsequent boundary completion.

Adult↗

PubMed2006

Perceived safety in disaster workers following 9/11.

The perception of being safe, perceived safety, is an important component of health and the ability to work after exposure to traumatic events of all kinds. The relationship of perceived safety to posttraumatic stress disorder and depression has rarely been examined. This study examined symptoms of posttraumatic stress disorder, depression, and perceived safety in disaster workers 2 weeks after the 9/11 terrorist attacks. Perceived safety was lower in those with greater exposure (e.g., those who felt they were in physical danger, worked with dead bodies, or witnessed someone being killed or seriously injured). Lower perceived safety was associated with greater symptoms of intrusion and hyperarousal but not avoidance. Safety was negatively correlated with depression and peritraumatic dissociation. Lowered perceptions of safety following terrorist events have implications for social and work-related behaviors that can affect long-term health, morale, and productivity in disaster workers and other first responders.

Adult↗

PubMed2005

Positive and negative consequences of a military deployment.

This study determined the perception by 951 U.S. Army soldiers of positive and negative consequences of a peacekeeping deployment to Bosnia. Seventy-seven percent reported some positive consequences, 63% reported a negative consequence, and 47% reported both. Written comments were also provided. Of the 951 soldiers, 478 wrote at least one positive comment and 403 at least one negative comment. Single soldiers were more likely than married soldiers to report positive consequences (82% vs. 72%). Married soldiers were more likely than single soldiers to report negative consequences (70% vs. 55%). Positive consequences included making additional money, self-improvement, and time to think. Negative consequences included the military chain of command, being away from home, and deterioration of marital/significant other relationships.

Attitude↗

PubMed2004

Spatiotemporal differences between cognitive processes of spatially possible and impossible objects: a high-density electrical mapping study.

Differences in cognitive processing between spatially possible and impossible figures were investigated using event-related potentials (ERPs). Two types of figures with identical luminance and equivalent spatial frequency were used as visual stimuli: possible three-dimensional figures (drawn with perspective and existing in the three-dimensional world) and impossible figures (drawn with perspective but not existing in the three-dimensional world). High-density electroencephalographic recording (72 channels) was performed for analysis of ERPs accompanying perception of each figure type; amplitude differences between the conditions were considered neurophysiologic correlates to perceptual differences between possible and impossible objects. Low-resolution brain electromagnetic tomography (LORETA) was used to identify the current source related to the differences. Compared with impossible three-dimensional figures, perception of possible figures showed a significant negative potential increase in the right inferior occipitotemporal region between 350 and 389 ms of latency. The current source was localized to the right fusiform gyrus. The results suggest that right fusiform gyrus is involved in discrimination between spatially possible and impossible objects.

Adult↗

PubMed2003

The effect of paroxetine on Taijinkyofusho: a report of three cases.

Taijinkyofusho is a culture-related syndrome conceptualized in Japan. While previous studies suggest its psychopathological similarities to social phobia and obsessive-compulsive disorder, introspection regarding shame and low self-esteem is particularly linked to Japanese culture. We present three cases of Taijinkyofusho: Cases 1 and 2 show neurotic features while Case 3 shows delusional thoughts. Paroxetine was used for treatment but was productive in only the first two cases. Phobic and obsessive thought patterns were altered in Cases 1 and 2, suggesting that the significant core symptoms were responding to the treatment. In the future, large-scale pharmacological studies will be necessary to investigate treatment outcomes Taijinkyofusho. Such studies would contribute to providing information for effective treatment as well as for examining relationships between Taijinkyofusho and related disorders.

Adult↗

PubMed2003

[Treatment of psychiatric patients with serious physical co-morbidity: administrative model in Tokyo].

In Japan, treatment of physical co-morbidity among psychiatric patients has been difficult in many aspects. Conflicts frequently arise when referrals are made from mental hospitals to general hospitals for many reasons, such as prejudice, lack of psychiatrists, and lack of psychiatric beds in general hospitals. Tokyo Metropolitan District, with over 12 million people in population, has suffered this problem, consequently leading to an establishment of a government-involved referral system in 1981. The government mediates between mental hospitals and designated treatment centers so that smooth transfers are made. After two decades of operation, the number of transferred patients via the system is on the increase. While this system still has many problems to be solved, it may become a model administrative system for other governments to apply and provide hints for effective treatment of med/psych cases.

Comorbidity↗

PubMed2002

Mental health issues of peacekeeping workers.

The end of the Cold War has brought a dramatic change to the international political situation and the role of the United Nations peacekeeping operations (PKO) has drawn increased attention. While many reports on PKO have focused on political or sociologic considerations, the mental health of the peacekeepers themselves has received little attention and psychiatric problems that can have a negative impact on mission success have been largely ignored. Participation in PKO creates a number of stressors and serious psychiatric and/or physical disorders may result. Yet, there is little research on this topic, either domestically or globally, and the methodology for clinical intervention remains in an early stage of development. We have reviewed previous reports to determine how various stressors before, during and after deployment affect the participants. Research in associated fields (e.g. crisis workers and military personnel) are also reviewed and their application to peacekeeping psychiatry is discussed. It must be admitted that the significance of PKO is arguable and each PKO is unique in terms of the nature of its mission and the local situation. Yet, the relationship between the psychiatric status of the personnel and the characteristics of an individual mission has never been studied. At present, no clear consensus regarding a framework for psychiatric intervention exists. Studies that enhance the recognition and significance of peacekeeping psychiatry are likely to improve the efficacy of PKO.

Crisis Intervention↗