Exploring the neurocognome: Neurocognitive network organization in healthy young adults

Conventional neurocognitive assessment does not account for the complex interplay between neurocognitive functions that gives rise to (goal-directed) behavior. This study aims to explore the value of the application of network analysis to individual neurocognitive data, in order to investigate neurocognitive network organization (i.e., the neurocognome). Participants were healthy young adults (N = 51, average age: 26 years [range: 18-34], 49% female) that underwent a single comprehensive neurocognitive assessment. To allow implementation of network analysis, we developed a new measure of connectivity between neurocognitive functions that can be calculated on a single neurocognitive assessment. Connectivity values between all possible pairs of neurocognitive functions were used to reconstruct individual neurocognitive networks. Graph theory was applied to extract measures of global and local network organization from neurocognitive networks at the individual level. The results confirmed the expectation that neurocognitive connectivity values should be higher for connections between neurocognitive functions that are more closely related (i.e., within neurocognitive domains) than for connections between neurocognitive functions that are less closely related (i.e., across neurocognitive domains). The results further showed that reconstruction of the neurocognitive network at the individual level has considerable agreement with a group-based approach, providing preliminary evidence for the validity of our approach. The reconstructed neurocognitive network also showed considerable consistency among (randomly selected) independent subgroups, supporting the stability of our approach. Lastly, neurocognitive network parameters were related to intelligence and behavior problems, reflecting relevance of neurocognitive network organization for other important domains of functioning. Moreover, local network parameters (i.e., the relative importance of neurocognitive functions in the network) may have stronger relevance for behavioral functioning than conventional measures of neurocognitive functioning (i.e., z-scores reflecting performance on individual neurocognitive tests). Taken together, this study indicates that analysis of individual neurocognitive network organization has potential value for neurocognitive assessment in research and clinical practice.