. Which one of the following externally applied devices is capable of enhancing or inhibiting motor ...

ANS: A
Rationale: TMS to the motor cortex and other brain areas involved in motor learning can either enhance or inhibit motor learning and memory formation, depending on the frequency and experimental protocol used. For example, TMS of the primary motor cortex enhances the duration of motor memory, and stimulation of the dorsal premotor cortex enhances motor memory consolidation. TMS is also used to induce a transient virtual lesion to assess the impact different brain areas have on motor learning. For example, inhibitory TMS applied to the primary somatosensory cortex impairs motor learning. Magnetic stimulation of the brain is thought to induce synaptic plasticity via LTP- or LTD-type mechanisms.