This study will explore sequence effect, a fatigue or tiredness commonly seen in patients with Parkinson's disease after they have been doing the same thing for a while. The study will use a new device called a modified peg board test (see description below) to measure whether antiparkinsonian medications (levodopa/carbidopa or dopamine) and repetitive transcranial magnetic stimulation (rTMS, see description below) of the brain can improve the symptoms of sequence effect.