Apparently they play a critical role in neurones (which can have millions of them) not only because the brain is the most energy hungry organe but also because they play numerous parts in how they work : neurotransmitter transporters and regulators, stress modulator, epigenetic "signalors"... the list goes on.
No wonder ketones can have an impact such as healing epilepsy just by the effect they have on mitochondria. It is quit a fascinating domain of research and the potential it is unravelling is huge IMHO.
- https://www.youtube.com/watch?v=Y6iJMDhLmLc