Congrats to Kate for their paper in PLoS:One. They investigate the effect of theta-frequency transcranial Alternating Current Stimulation during declarative learning (Swahili-Dutch word pairs). They predicted an interaction between stimulation and prediction error, but this was not observed. The basic reward prediction error effect in declarative memory, however, was robustly observed.
Reference: Ergo, K., De Loof, E., Debra, G., Pastötter, B., & Verguts, T. (2021). Failure to modulate reward prediction errors in declarative learning with theta (6 Hz) frequency transcranial alternating current stimulation. PloS One.