On the role of the SMA in the discrete sequencenext term production task: a TMS study

Participants practiced two previous termdiscretenext term six-key previous termsequencesnext term for a total of 420 trials. The 1×6 previous termsequencenext term had a unique order of key presses while the 2×3 previous termsequencenext term involved repetition of a three-key segment. Both previous termsequencesnext term showed a long interkey interval halfway the previous termsequencenext term indicating hierarchical previous termsequencenext term control previous terminnext term that not only the 2×3 but also the 1×6 previous termsequencenext term was executed as two successive motor chunks. Besides, the second part of both previous termsequencesnext term was executed faster than the first part. This supports the earlier notion of a motor processor executing the elements of familiar motor chunks and a cognitive processor triggering either these motor chunks or individual previous termsequencenext term elements. Low-frequency, off-line transcranial magnetic stimulation (TMS) of the supplementary motor area (previous termSMA)next term counteracted normal improvement with practice of key presses at all previous termsequencenext term positions. Together, these results are previous terminnext term line with the notion that with moderate practice, the previous termSMAnext term executes short previous termsequencenext term fragments that are concatenated by other brain structures