TABLE 4.

Description of the key characteristics of correlation and association networks.

Correlation and association networks’ main characteristics
Nodes	Features (intensity), low-level annotations (m/z)
Edges	Correlation between the abundances of two metabolites
Main Hypothesis	Metabolic processes imply metabolites’ abundance that depends on other metabolites’ abundance. Thus, metabolites with correlated abundance might be metabolically related
Limitations	The correlation or association between two metabolites (or features) does not systematically represent a metabolic relationship (e.g., substrate-product) or interdependence (e.g., co-regulation). Thus, correlation does not necessarily imply causal, biological, or chemical relationships