A freshly-harvested Sprague Dawley rat brain is dissected and the cerebral cortex is flash-frozen in liquid nitrogen and stored frozen until lysis. The tissue is ground and thoroughly homogenized at 4C with a freshly prepared modified Radio Immuno Precipitation Assay (RIPA) buffer containing strong protease and phosphatase inhibitor cocktails. The final homogenate is incubated with DNase then clarified by centrifugation at 10,000 g at 4C and stored at -80C. Each lot is quality controlled by determining the protein concentration using a BCA assay and analyzed with SDS-PAGE using Coomassie blue for visualization. Sharp, clear protein bands indicate a quality protein lysate.