Gene Ontology nodes differentially expressed in motor cortex of SALS subjects. Significant Gene Ontology (GO) nodes were combined to groups likely representing major processes in the context of ALS pathology, specifically energy metabolism, ion homeostasis and solute transport, defense signaling, protein modification and turnover, cytoskeleton, and glycolysis, and are arranged indicating the predominant intracellular localization of the gene products they comprise. The basic categories Biological Process, Cellular Component, and Molecular Function are color-coded. Connecting arrows indicate the order of nodes in the GO hierarchy. For each major process only the highest node(s) of significance (◇) and the most significant node (!) are shown per basic category. Up- () and down-regulation (), the absolute number and percentage of genes meeting the criterion, z score, and corrected P value are indicated for each node. Redundant nodes are left out within the same category, or combined if in different categories.