Kimiko Kato

Hemisphere Division and its Effect on Selective Attention: A Generality Examination of Lavie's Load Theory

The present study examined the role of visual presentation mode (unilateral vs. bilateral visual fields) on attentional modulation. We examined whether or not the presentation mode affects the compatibility effect, using a paradigm involving two task-relevant letter arrays. Sixteen participants identified a target letter among task-relevant letters while ignoring either a compatible or incompatible distracter letter that was presented to both hemispheres. Two letters arrays were presented to visual fields, either unilaterally or bilaterally. Results indicated that the compatibility effect was greater in bilateral than in unilateral visual field conditions. Findings support the assumption that the two hemispheres have separate attentional resources.

Early functional network alterations in asymptomatic elders at risk for Alzheimer’s disease

Amyloid-β (Aβ) deposition is known to starts decades before the onset of clinical symptoms of Alzheimer’s disease (AD), however, the detailed pathophysiological processes underlying this preclinical period are not well understood. This study aimed to investigate functional network alterations in cognitively intact elderly individuals at risk for AD, and assessed the association between these network alterations and changes in Aβ deposition, glucose metabolism, and brain structure. Forty-five cognitively normal elderly subjects, who were classified into Aβ-positive (CN+) and Aβ-negative (CN−) groups using 11C-Pittsburgh compound B PET, underwent resting state magnetoencephalography measurements, 18F-fluorodeoxyglucose PET (FDG-PET) and structural MRI. Results demonstrated that in the CN+ group, functional connectivity (FC) within the precuneus was significantly decreased, whereas it was significantly enhanced between the precuneus and the bilateral inferior parietal lobules in the low-frequency bands (theta and delta). These changes were suggested to be associated with local cerebral Aβ deposition. Most of Aβ+ individuals in this study did not show any metabolic or anatomical changes, and there were no significant correlations between FC values and FDG-PET or MRI volumetry data. These results demonstrate that functional network alterations, which occur in association with Aβ deposition, are detectable using magnetoencephalography before metabolic and anatomical changes are seen.

Priority for one's own stimulus in joint performance: evidence from an event-related potential study.

To investigate priority of shared task representations (own vs. other) formed during joint task performance, event-related potentials were recorded while participants performed an auditory three-stimulus oddball task alone (individual condition) and with another participant (joint condition). Participants were required to discriminate between frequent standard tones and rare target tones, while ignoring nontargets assigned to a partner’s action (i.e. no-go stimuli for one’s own task performance). The parietal P3b was elicited for targets under both conditions. In contrast, P3b for nontargets was observed only in the joint condition, and in addition, it accompanied the frontal no-go P3. This implies that coactors share one another’s task representations. Importantly, the emergence of P3b and no-go P3 for nontargets was delayed compared with P3b for targets, suggesting that shared task representations are serially applied to the stimulus processing and that one’s own representations precede the other individual’s representations.

Relations Between Exercise Habit and Visual Attentional Ability in Older Adult Community Dwellers: Evidences From the Yakumo Study:

Objective: The relation between mild everyday exercise and cognitive ability in healthy older people was examined using cohort study database. Methods: Individually calculated linear regression coefficients in digit cancelation task performances for 11 years age from 65 to 75 years were compared between mild exercise habit holders and non-holders. Results: Exercise habit holders showed significantly smaller age-related decline than non-holders, irrespective of task difficulty. Discussion: The results suggested that even mild exercise habit for long years possesses benefits on sustaining cognitive function in older people as well as the physical activities such as programmed in a sport gym. It also becomes clear that it is difficult for ordinary older adult to continue exercising habits for many years. Therefore, more substantial ways are required for local health officials to advertise the effectiveness of mild exercise habits and to devise the necessary work to become a habit.

Age-Related Changes in Attentional Control Using an N-Back Working Memory Paradigm

Background/Study Context: Older adults tend to be affected by task-irrelevant distracters. However, whether or not this aging effect is evident when task-irrelevant and relevant stimuli are presented across different sensory modalities is still a subject of debate. The purpose of the present study was to clarify age-related differences in the effects of auditory distraction on visual information processing. Methods: Participants included 20 young individuals, 20 younger-old individuals in their 60s, and 20 older-old individuals in their 70s. Visual n-back (1-back, 2-back) working memory (WM) tasks using Japanese words were examined with and without auditory distracter conditions. Participants’ performances were analyzed using a three-way analysis of variance: 3 (age group) × 2 (distraction) × 2 (working memory load). Results: The effects of auditory distractions were influenced by aging and WM load. Auditory distractions disturbed WM performances preferentially in older adults. Further, participants in the older-old group were more affected by auditory distractions than those in the younger-old group, especially during the 2-back task. Conclusion: These results suggested that the WM performances for visual n-back tasks were largely disturbed by auditory distractions in older adults but not in young adults.

CORRELATION BETWEEN CORTICAL EXCITABILITY AND LOCAL β-AMYLOID DEPOSITION AS EVALUATED BY MEG AND PIB-PET

P4-117 CORRELATION BETWEEN CORTICAL EXCITABILITYAND LOCAL b-AMYLOID DEPOSITION AS EVALUATED BY MEG AND PIB-PET Akinori Nakamura, Takashi Kato, Misako Yamagishi, Kaori Iwata, Masahiko Bundo, Kimiko Kato, Hideyuki Hattori, Takashi Sakurai, Yutaka Arahata, Maess Burkhard, Kengo Ito, Study Group MULNIAD, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan; National Center for Geriatrics and Gerontology, Obu, Aichi, Japan; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. Contact e-mail: nakamura@ncgg.go.jp