How do brain zaps occur?
Here's the only speculation I could find about brain shivers aka brain zaps.

Cortes JA, Radhakrishnan R. A Case of Amelioration of Venlafaxine-Discontinuation “Brain Shivers” With Atomoxetine The Primary Care Companion for CNS Disorders. 2013;15(2):PCC.12l01427. doi:10.4088/PCC.12l01427.

It proposes an explanation related to norepinephrine. Also, it claims that brain shivers or brain zaps are related to Lhermitte's phenomenon. I have mixed feelings about this specific comparison from what I've witnessed.

"These facts point to the possibility that increases in synaptic norepinephrine are due to norepinephrine transporter reversal, akin to dopamine transporter reversal associated with amphetamine. Abrupt withdrawal of venlafaxine would hence result in paradoxical increase in synaptic norepinephrine via efflux through norepinephrine transporter channels, which is normalized by atomoxetine’s norepinephrine transporter blockade."

That would explain brain zaps from stopping tramadol and SNRIs too, by the way: a noradrenergic syndrome.

Anyone has a better or more supported speculation?