Figure 1.

Experimental design. All participants performed a sequential finger-tapping task, in which they were trained to repeatedly perform with their nondominant left hand a constant sequence of five finger movements, with performance measured as the number of correct sequences during each fixed 10 s trial (Karni et al., 1995; Korman et al., 2007; Censor et al., 2010). Following initial memory formation and test subjects were divided into 2 groups. To interfere with memory modification, one group was stimulated with 1-Hz rTMS applied to the primary motor cortex (M1) during memory reactivation trials. The second group received control rTMS to a vertex position applied simultaneously with peripheral nerve stimulation (ulnar nerve at the wrist) to mimic disruption of manual performance present when stimulating M1 without reducing memory modification (see Fig. 2). Memory modification and fMRI measurements were assessed on a retest the following day.