Purpose: Recently, many studies have demonstrated that application of external stimulation can modulate cortical excitability of the human brain. We attempted to observe cortical excitability using functional magnetic resonance imaging (fMRI) during the application of transcranial direct current stimulation (tDCS) or functional electrical stimulation (FES). Methods: We recruited two healthy subjects without a history of neurological or psychiatric problems. fMRI scanning was done during? each constant anodal tDCS and FES session, and each session was repeated three times. The tDCS session consisted of three successive phases (resting phase: 60sec dummy cycle: 10sec tDCS phase: 60sec). The FES session involved stimulation of wrist extensor muscles over two successive phase (resting phase: 15sec FES phase: 15sec). Results: The average map of the tDCS and FES analyses showed that the primary sensory-motor cortex area was activated in all subjects. Conclusion: Our findings show that cortical activation can be induced by constant anodal tDCS and FES. They suggest that the above stimuli have the potential for facilitating brain plasticity and modulating neural excitability if applied as specific therapeutic interventions for brain injured patients.