When you follow the linked articles down the rabbit hole, it leads to AMPAkines which are positive allosteric neuromodulators.
Ampakines work by allosterically binding to a type of ionotropic glutamate receptor, called AMPA receptors.
These are also being studied for sleep apnea treatment.
For anyone wanting an easy read article to assist in better understanding BDNF:
https://www.frontiersin.org/articles/10.3389/fncel.2019.00363/full
Sleep apnea can be treated by taking vitamin B1. A friend of ours took it for his apnea, and it worked.