I would (slightly) disagree with that. The hope is often to enhance whatever's already going on in the brain--and this is a sensible goal because there's often

I would (slightly) disagree with that. The hope is often to enhance whatever's already going on in the brain--and this is a sensible goal because there's often less neural synchrony in some diseases (e.g, schizophrenia) or situations (e.g., memory lapses). However, the brain has its own internal dynamics--and they're complicated! You can 't just blithely write a new thing on top of them and expect it to work. In our experiments, doing so often backfires: stimulating at 5 Hz often makes makes cells already firing at 5 Hz act less rhythmically, not more. The reason is that the brain's oscillations drift in frequency and abruptly reset, so they "compete" with the imposed oscillation. This is a pretty well-studied phenomeon in other contexts (e.g., sloshing in rocket fuel tanks or nearby pipes cancelling each other in organs). TI is exciting because you could potentially sense what's going on and adjust the stimulation accordingly, but we've got a lot of work to go.