Figure 1.

A conceptual model of potential interactions between brain structure, functional activity, their relationship to cognitive outcome and the potential roles of cognitive reserve. This simplified model is not exhaustive in showing all of the potential relationships between the variables but includes paths based on our previous findings: ‘pathology → network expression’ (Steffener, et al., 2009) and ‘network expression → task performance’ (Zarahn, et al., 2007), the model includes 'CR → network expression' supporting the idea that CR influences the expression of the functional networks; ‘pathology → CR’ supporting the concept that at some point pathology must become too severe to support the processes that underlie CR (Y. Stern, 2009). In addition, the path ‘CR → performance’ supports the idea that CR may be operating via its own common network, which is unrelated to the expression of the task-related functional networks supporting task performance (Y. Stern, et al., 2008) and the path ‘pathology → performance’ supports the idea that pathology may be affecting performance in a manner not captured by the other factors included in the model.