GLUL and amyotrophic lateral sclerosis: Striatal cluster 0 had the highest activation of an amyotrophic lateral sclerosis signaling pathway (z = 1, p < 4e-6) and glutamate receptor signaling (z = 0.38, p < 1e-8) due to the high expression of overlapping genes that encode proteins responsible for glutamate-glutamine cycling in astrocytes (Slc1a2, Glul, Gria1, Grid1, and Grin2c).