Effect of Parietal Transcranial Magnetic Stimulation on Spatial Working Memory in Healthy Elderly Persons - Comparison of Near Infrared Spectroscopy for Young and ElderlyReportar como inadecuado




Effect of Parietal Transcranial Magnetic Stimulation on Spatial Working Memory in Healthy Elderly Persons - Comparison of Near Infrared Spectroscopy for Young and Elderly - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

In a previous study, we succeeded in improving the spatial working memory WM performance in healthy young persons by applying transcranial magnetic stimulation TMS to the parietal cortex and simultaneously measuring the oxygenated hemoglobin oxy-Hb level using near-infrared spectroscopy NIRS. Since an improvement in WM was observed when TMS was applied to the right parietal cortex, the oxy-Hb distribution seemed to support a model of hemispheric asymmetry HA. In the present study, we used the same study design to evaluate healthy elderly persons and investigated the effect of TMS on WM performance in the elderly, comparing the results with those previously obtained from young persons. The application of TMS did not affect WM performance both reaction time and accuracy of 38 elderly participants mean age  = 72.5 years old. To investigate the reason for this result, we conducted a three-way ANOVA examining oxy-Hb in both young and elderly participants. For the right parietal TMS site in the elderly, TMS significantly decreased the oxy-Hb level during WM performance; this result was the opposite of that observed in young participants. An additional three-way ANOVA was conducted for each of the 52 channels, and a P value distribution map was created. The P value maps for the young participants showed a clearly localized TMS effect for both the WM and control task, whereas the P map for the elderly participants showed less significant channels and localization. Further analysis following the time course revealed that right-side parietal TMS had almost no effect on the frontal cortex in the elderly participants. This result can most likely be explained by age-related differences in HA arising from the over-recruitment of oxy-Hb, differentiation in the parietal cortex, and age-related alterations of the frontal-parietal networks.



Autor: Kaori Yamanaka , Hiroi Tomioka, Shingo Kawasaki, Yumiko Noda, Bun Yamagata, Akira Iwanami, Masaru Mimura

Fuente: http://plos.srce.hr/



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