Faculty Profiles - OHIRA, Hideki

Psychopathic traits and cardiovascular responses to emotional stimuli

Osumi T., Shimazaki H., Imai A., Sugiura Y., Ohira H.

Personality and Individual Differences Vol. 42 ( 7 ) page： 1391 - 1402 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：Personality and Individual Differences

DOI： 10.1016/j.paid.2006.10.016

Crossmodal effect with rubber hand illusion and gamma-band activity

Psychopathic traits and cardiovascular responses to emotional stimuli

Osumi Takahiro, Shimazaki Hiroshi, Imai Akira, Sugiura Yoshinori, Ohira Hideki

PERSONALITY AND INDIVIDUAL DIFFERENCES Vol. 42 ( 7 ) page： 1391 - 1402 2007.5

Noriaki Kanayama, Atsushi Sato, Hideki Ohira

PSYCHOPHYSIOLOGY Vol. 44 ( 3 ) page： 392 - 402 2007.5

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

The integration of multimodal stimuli has been regarded as important for the promotion of adaptive behavior. Although recent work has identified brain areas that respond to multimodal stimuli, the temporal features are not clear yet. Earlier event-related potential studies revealed crossmodal attention effects, but did not focus on mechanisms underlying crossmodal integration. Here, electroencephalography (EEG) activity in the gamma band was considered as a correlate of multimodal integration. Participants localized a tactile stimulus on their fingers while seeing visual stimuli on rubber hands with the same posture as their hands. EEG analyses using wavelet transform suggested that interelectrode phase synchrony in the gamma-band range (40-50 Hz) was related to behavioral indices of the intermodal illusion under consideration. The findings suggest a role of high-frequency oscillations in the integrative processing of stimuli across modalities.

DOI： 10.1111/j.1469-8986.2007.00511.x

Exploring Stress Processes by Neuroimaging

OHIRA Hideki

Vol. 62 ( 2 ) page： 242 - 243 2007.3

An ERP study on self-relevant object recognition. Reviewed International journal

Makoto Miyakoshi, Michio Nomura, Hideki Ohira

Brain and cognition Vol. 63 ( 2 ) page： 182 - 9 2007.3

Language：English Publishing type：Research paper (scientific journal)

We performed an event-related potential study to investigate the self-relevance effect in object recognition. Three stimulus categories were prepared: SELF (participant's own objects), FAMILIAR (disposable and public objects, defined as objects with less-self-relevant familiarity), and UNFAMILIAR (others' objects). The participants' task was to watch the stimuli passively. Results showed that left-lateralized N250 activity differentiated SELF and FAMILIAR from UNFAMILIAR, but SELF and FAMILIAR were not differentiated. In the later time-course, SELF was dissociated from FAMILIAR, indicating the self-relevance effect in object recognition at this stage. This activity did not show consistent lateralization, in contrast to previous studies reporting right lateralization in self-relevant face and name recognition. We concluded that in object recognition, self-relevance was processed by higher-order cognitive functions later than 300ms after stimulus onset.

An ERP study on self-relevant object recognition

Makoto Miyakoshi, Michio Nomura, Hideki Ohira

BRAIN AND COGNITION Vol. 63 ( 2 ) page： 182 - 189 2007.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

We performed an event-related potential study to investigate the self-relevance effect in object recognition. Three stimulus categories were prepared: SELF (participant's own objects), FAMILIAR (disposable and public objects, defined as objects with less-self-relevant familiarity), and UNFAMILIAR (others' objects). The participants' task was to watch the stimuli passively. Results showed that left-lateralized N250 activity differentiated SELF and FAMILIAR from UNFAMILIAR, but SELF and FAMILIAR were not differentiated. In the later time-course, SELF was dissociated from FAMILIAR, indicating the self-relevance effect in object recognition at this stage, This activity did not show consistent lateralization, in contrast to previous studies reporting right lateralization in self-relevant face and name recognition. We concluded that in object recognition, self-relevance was processed by higher-order cognitive functions later than 300 ms after stimulus onset. (C) 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bandc.2006.12.001

An electrophysiological comparison of recollection for emotional words using an exclusions recognition paradigm Reviewed

Midori Inaba, Kyoko Kamishima, Hideki Ohira

BRAIN RESEARCH Vol. 1133 ( 1 ) page： 100 - 109 2007.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The positive-going shift of event-related potential (ERP) components that occur when recognizing emotional words has been thought to be due to valence effects on either recollection or familiarity. This study investigated the independent contributions of recollection and familiarity on recognition of emotional words in order to examine which is thus responsible for the greater magnitude of ERP components seen in response to recognition of emotional, as opposed to neutral words. ERPs were measured while participants completed an exclusion recognition task. In the test phase, participants were required to respond "old" only to target items, which were included in one of two lists that were presented in the study phase. They were also asked to respond "new" to distracters and non-target items that were in the other previously presented list. "Old" responses to targets and non-targets were contrasted with an ERP analysis. Results suggested that the late positivity reflected recollection. The magnitude of this positivity, elicited around the left parietal area, was greater for negative stimuli compared to neutral and positive stimuli. The findings of the present study suggested that enhanced recollection of negative words may contribute to increased magnitudes of components such as the LPC. The emotional valence of words may have separate behavioral and electrophysiological effects on recollection and familiarity. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.brainres.2006.07.010

Phylogenetic relationships of click beetles (Coleoptera : Elateridae) inferred from 28S ribosomal DNA: Insights into the evolution of bioluminescence in Elateridae

Sagegami-Oba Reiko, Oba Yuichi, Ohira Hitoo

MOLECULAR PHYLOGENETICS AND EVOLUTION Vol. 42 ( 2 ) page： 410 - 421 2007.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Molecular Phylogenetics and Evolution

Although the taxonomy of click beetles (family Elateridae) has been studied extensively, inconsistencies remain. We examine here the relationships between species of Elateridae based on partial sequences of nuclear 28S ribosomal DNA. Specimens were collected primarily from Japan, while luminous click beetles were also sampled from Central and South America to investigate the origins of bioluminescence in Elateridae. Neighbor-joining, maximum-parsimony, and maximum-likelihood analyses produced a consistent basal topology with high statistical support that is partially congruent with the results of previous investigations based on the morphological characteristics of larvae and adults. The most parsimonious reconstruction of the "luminous" and "nonluminous" states, based on the present molecular phylogeny, indicates that the ancestral state of Elateridae was nonluminous. This suggests that the bioluminescence in click beetle evolved independent of that of other luminous beetles, such as Lampyridae, despite their common mechanisms of bioluminescence. © 2006 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.ympev.2006.07.017

Psychological effects of forest environments on healthy adults: Shinrin-yoku (forest-air bathing, walking) as a possible method of stress reduction

Morita E., Fukuda S., Nagano J., Hamajima N., Yamamoto H., Iwai Y., Nakashima T., Ohira H., Shirakawa T.

PUBLIC HEALTH Vol. 121 ( 1 ) page： 54 - 63 2007.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Public Health

Objectives: Shinrin-yoku (walking and/or staying in forests in order to promote health) is a major form of relaxation in Japan; however, its effects have yet to be completely clarified. The aims of this study were: (1) to evaluate the psychological effects of shinrin-yoku in a large number of participants; and (2) to identify the factors related to these effects. Methods: Four hundred and ninety-eight healthy volunteers took part in the study. Surveys were conducted twice in a forest on the same day (forest day) and twice on a control day. Outcome measures were evaluated using the Multiple Mood Scale-Short Form (hostility, depression, boredom, friendliness, wellbeing and liveliness) and the State-Trait Anxiety Inventory A-State Scale. Statistical analyses were conducted using analysis of variance and multiple regression analyses. Results: Hostility (P<0.001) and depression (P<0.001) scores decreased significantly, and liveliness (P=0.001) scores increased significantly on the forest day compared with the control day. The main effect of environment was also observed with all outcomes except for hostility, and the forest environment was advantageous. Stress levels were shown to be related to the magnitude of the shinrin-yoku effect; the higher the stress level, the greater the effect. Conclusions: This study revealed that forest environments are advantageous with respect to acute emotions, especially among those experiencing chronic stress. Accordingly, shinrin-yoku may be employed as a stress reduction method, and forest environments can be viewed as therapeutic landscapes. Therefore, customary shinrin-yoku may help to decrease the risk of psychosocial stress-related diseases, and evaluation of the long-term effects of shinrin-yoku is warranted. © 2006.

DOI： 10.1016/j.puhe.2006.05.024

L-Theanine reduces psychological and physiological stress responses Reviewed

Kenta Kimura, Makoto Ozeki, Lekh Raj Juneja, Hideki Ohira

BIOLOGICAL PSYCHOLOGY Vol. 74 ( 1 ) page： 39 - 45 2007.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

L-Theanine is an amino acid contained in green tea leaves which is known to block the binding of L-glutamic acid to glutamate receptors in the brain. Because the characteristics of L-Theanine suggest that it may influence psychological and physiological states under stress, the present study examined these possible effects in a laboratory setting using a mental arithmetic task as an acute stressor. Twelve participants underwent four separate trials: one in which they took L-Theanine at the start of an experimental procedure, one in which they took L-Theanine midway, and two control trials in which they either took a placebo or nothing. The experimental sessions were performed by double-blind, and the order of them was counterbalanced. The results showed that L-Theanine intake resulted in a reduction in the heart rate (HR) and salivary immunoglobulin A (s-IgA) responses to an acute stress task relative to the placebo control condition. Moreover, analyses of heart rate variability indicated that the reductions in HR and s-IgA were likely attributable to an attenuation of sympathetic nervous activation. Thus, it was suggested that the oral intake of L-Theanine could cause anti-stress effects via the inhibition of cortical neuron excitation. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.biopsycho.2006.06.006