Performance at learning and retention.

Mean ± SEM values are given for performance at learning and retention performance on the declarative word paired-associate task and the two procedural tasks, i.e., finger sequence tapping and mirror tracing. Retention is defined by the difference in performance at retrieval testing (morning after sleep) minus performance at immediate recall at learning (evening before sleep). No significant differences between the theta-tDCS and sham conditions were found for performance at learning.**P