One placebo-controlled study examined the effect of lipoic acid on the visual capability of 80 participants of whom 12 had type 1 diabetes, 48 had type 2 diabetes, and 20 were diabetes-free
Gao L, Zhang J, Chan P, Wu T (2017) Levodopa effect on basal ganglia motor circuit in parkinsons disease
First, the effect is enzymatic and cumulative you are shifting a metabolic set-point over days and weeks, not triggering an acute hormonal event, which is why steady daily exposure matters more than any single large dose
It is true that in certain neurological conditions, the brain may undergo plastic changes and compensate for deficits in signal transmission
And you dont have to worry about getting too much because its been reported that there are no reports of adverse effects associated with excess B12 intakebut thats not true