The present invention provides a novel class of heterocyclic compounds of Formula (I) as modulators of gamma secretase, wherein the definitions of the variables of Formula (I) are defined herein, methods of preparing such compounds, pharmaceutical compositions containing one or more such compounds, methods of preparing pharmaceutical formulations comprising one or more such compounds, and methods of treatment, prevention, inhibition, or amelioration of one or more diseases associated with the central nervous system using such compounds or pharmaceutical compositions.