Inclusion Criteria:  Chemotherapy to treat breast cancer (≥ 6 months post-treatment). Self-reported concerns regarding cognitive functioning. Age: 18-60 years.  Exclusion Criteria:  History of dementia before treatment of cancer. Other neurodegenerative neurological disorders; epilepsy or history of seizures. Severe and untreated medical conditions that preclude participation in the training, as determined by responsible physician. History of moderate to severe substance use disorder according to DSM-5 Moderate to severe acute psychiatric disorders according to DSM-5 Contraindication to tDCS application (Antal et al., 2017)