Neuronal functioning was found to become impaired by a high fat diet in a recent study.  

Neurons require internal energy to be released for optimal functioning.  Their long axons contain mitochondria, small organelles that release chemical energy stored as ATP.  Saturated fatty acids affect the mitochondrial energy release process adversely in mice. 

As this is a key component of the popular Keto Diet, research interest could increase.

Is the Keto Diet Healthy for Neurons? High Dietary Fat Consumption impairs Axonal Mitochondrial Function in vivo