Alpha-band activity (8-13 Hz) is suppressed by sensory stimulation and movements, modulated by attention, working memory and mental tasks and may be sensitive to higher motor control functions. The aim of the present study was to examine alpha oscillatory activity during the preparation of simple left or right finger movements, contrasting the external and internal mode of action selection. Three preparation conditions were examined using a precueing paradigm with S1 as the preparatory and S2 as the imperative cue: Full, laterality instructed by S1; Free, laterality freely selected and None, laterality instructed by S2. Time-frequency analysis was performed in the alpha frequency range during the S1-S2 interval, and alpha motor-related amplitude asymmetries (MRAA) were also calculated. The significant MRAA during the Full and Free conditions indicated effective external and internal motor response preparation. In the absence of specific motor preparation (None), a posterior alpha power decrease (event-related desynchronization, ERD) dominated, reflecting the main engagement of attentional resources. In Full and Free motor preparation, posterior alpha ERD was accompanied by a midparietal alpha power increase (event-related synchronization, ERS), suggesting a concomitant inhibition of task-irrelevant visual activity. In both Full and Free motor preparation, analysis of alpha power according to MRAA amplitude revealed two types of functional activation patterns: 1) a motor alpha pattern, with predominantly midparietal alpha ERS and large MRAA corresponding to lateralized motor activation/visual inhibition and 2) an attentional alpha pattern, with dominating right posterior alpha ERD and small MRAA reflecting visuospatial attention. The present results suggest that alpha oscillatory patterns do not resolve the selection mode of action, but rather distinguish separate functional strategies of motor preparation.
1 September 2010 in Archives of Gerontology and Geriatrics
This study explores the interrelationships between health-related quality of life and conflict structures in family networks of older adults. Data were derived from a sample of 2,858 elders (aged 65 years and older) from the Vivre/Leben/Vivere study, a large survey addressing family life and health conditions of older people in Switzerland. Conflict density in family networks and the betweenness centrality of respondents in family conflict are significantly associated with health-related quality of life measures. Furthermore, the results demonstrate that conflict–health associations are mediated by the level of perceived individual stress where psychological health is concerned. Family conflict structures depend to a large extent on family composition and age. This study stresses the importance of older adults actively shaping the composition of their family contexts in ways that promote both conflict and stress avoidance.