Inclusion Criteria:  Community-dwelling adults aged 65 years and older, with cognitive complains in memory or other functions, which have declined over time  Exclusion Criteria:  Score in the mini mental examination less than 23 (or over 28); Diagnosis of Alzheimer´s Disease, any other medical condition that may predispose participants for a forthcoming decline in function, or that may increase their risk of mortality during the duration of the study. Any contra-indication to tACS, severe sensory losses or communication difficulties that will prevent them from successfully complete the training. Had any cognitive training in the past.