Induction of plasticity and metaplasticity using noninvasive brain stimulation.

Noninvasive brain stimulation (NIBS) methods can modulate brain plasticity, the fundamental process by which synaptic connections are strengthened or weakened in response to synaptic activity or external stimuli. This review synthesizes current knowledge regarding how NIBS techniques induce long-lasting synaptic changes resembling long-term potentiation (LTP) and long-term depression (LTD). We place special emphasis on metaplasticity, the process by which prior neural activity influences subsequent plasticity responses. We highlight how various stimulation parameters, brain state, and individual differences shape plasticity outcomes, and emphasize the challenges in achieving consistent therapeutic effects. Additionally, we discuss the potential clinical impact of applying metaplasticity concepts in the treatment of neurological and psychiatric disorders. We outline critical areas for future research and emphasize the importance of developing personalized NIBS protocols that are closely aligned with underlying biological mechanisms to improve therapeutic outcomes.