Task-related measures of short-interval intracortical inhibition and GABA levels in healthy young and older adults: A multimodal TMS-MRS study oleh K. Cuypers, S. Verstraelen, C. Maes, L. Hermans, M. Hehl, K.-F. Heise, S. Chalavi, M. Mikkelsen, R. Edden, O. Levin, S. Sunaert, R. Meesen, D. Mantini, S.P. Swinnen