“…In several studies, the late phase, but not the early, was accompanied by changes in primary motor cortex (MI): imaging techniques revealed increased activity when humans learned new sequential finger movements (Ungerleider et al, 2002), and motor map reorganization and synapse formation have been observed when rats learned a novel multijoint reachand-grasp task (Kleim et al, 2004). These findings, together with a diversity of findings showing learning-dependant plasticity in MI (Sanes and Donoghue, 2000), suggest that a representation of the newly acquired skill is formed in MI during the late stages of learning, hence allowing for efficient generation and control of well trained movements (Porter and Lemon, 1993;Scott, 2004). Lately, several studies have reported changes in MI within a time scale of one session, i.e., dozens of trials (Laubach et al, 2000;Li et al, 2001;Cohen and Nicolelis, 2004).…”